Volcanos

Roundup of Global Volcanic Activity – Ongoing Activity for the week 12 January – 18 January 2022

Aira – Kyushu (Japan) : JMA reported that incandescence from Minamidake Crater (at Aira Caldera’s Sakurajima volcano) was visible at night during 10-17 January. Seismic data showed a decreasing number of volcanic earthquakes.

Fuego – Guatemala : INSIVUMEH reported that 6-13 explosions per hour were recorded at Fuego during 12-18 January, generating ash plumes that rose as high as 1.1 km above the crater rim. The ash plumes mainly drifted 10-20 km S and SW causing almost daily ashfall in areas downwind including Morelia (9 km SW), Panimaché I and II (8 km SW), Santa Sofía (12 km SW), El Porvenir (8 km ENE), Sangre de Cristo (8 km WSW), and La Rochela. Ash plumes drifted as far as 20 km E and NE during 14-16 January. Daily, periodic shock waves rattled structures in communities around the volcano. Block avalanches descended the flanks in all directions, but most commonly were visible in the Ceniza (SSW), Seca (W), Trinidad (S), Taniluyá (SW), Honda, and Las Lajas (SE) drainages, often reaching vegetated areas. Explosions ejected incandescent material up to 150-350 m above the summit during 12-16 January.

Great Sitkin – Andreanof Islands (USA) : AVO reported that slow lava effusion at Great Sitkin continued during 12-18 January, though cloudy conditions prevented satellite and webcam confirmation. Seismicity was very low and small events were occasionally recorded. Steam emissions were observed in webcam views during 14-15 January.

Karymsky – Eastern Kamchatka (Russia) : KVERT reported increased explosive activity at Karymsky and a thermal anomaly visible in satellite images during 7-8 and 11-12 January. Explosions during 11-13 January produced ash plumes that drifted almost 130 km in various directions.

Kilauea – Hawaiian Islands (USA) : HVO reported that lava effusion resumed at the vent in the lower W wall of Kilauea’s Halema`uma`u Crater at around 1840 on 11 January. The level of the lava lake had increased 13 m by about 0300 on 12 January, slightly surpassing the level prior to the pause that began on 10 January; the lake has risen a total of 70 m since the beginning of the eruption. During 12-14 January the lake was active and lava oozed out along the crusted-over E margins. A surge in lava effusion at the vent was recorded at 0545 on 15 January, coincident with a peak in summit inflation. Effusion had paused by the afternoon, though minor activity at the vent on the N side of the spatter cone, minor overturns of the lake, and small oozes of lava at the lake’s margins persisted. The lake level dropped 10 m by the morning of 16 January. Small overturns of the crusted lake were visible during 16-17 January. By 18 January the lake was completely crusted over and a small wispy plume rose from the vent.

Lewotolok – Lembata Island (Indonesia) : PVMBG reported that the eruption at Lewotolok continued during 11-16 January. Ash plumes rose as high as 700 m above the summit and drifted E, SE, and W during 11-14 January. Incandescent material ejected up to 300-700 m SE from the vent was accompanied by rumbling and banging noises. Eruption noises persisted through 16 January but weather prevented visual confirmation of activity during 15-16 January.

Merapi – Central Java (Indonesia) : BPPTKG reported no significant morphological changes at Merapi’s lava domes, located just below the SW rim and in the summit crater, during 6-13 January. The intensity of the seismic signals remained at high levels. As many as 123 lava avalanches traveled a maximum of 2.2 km SW down the Bebeng drainage, and four pyroclastic flows traveled a maximum of 2.5 km SW.

Pavlof – United States : AVO reported that elevated seismicity at Pavlof during 12-18 January was characterized by daily periods of tremor. Elevated surface temperatures consistent with lava effusion near the vent and the active lava flow on the SE flank were identified in satellite images almost daily; weather clouds prevented views for periods of time during 12-13 January.

Rincon de la Vieja – Costa Rica : OVSICORI-UNA reported that at 0024 on 13 January a two-minute eruption was recorded at Rincón de la Vieja, though weather clouds prevented visual confirmation. Residents to the N heard the eruption and felt vibrations, and lahars were seen in the Rio Azul. Small eruptive events were recorded at 1153 on 15 January and 1243 on 18 January, but plumes were not visible due to weather clouds.

Semeru – Eastern Java (Indonesia) : PVMBG reported that the eruption at Semeru continued during 12-17 January. White steam plumes that were sometimes dense rose as high as 1 km above the summit almost daily, and crater incandescence was visible nightly. Incandescent avalanches traveled as far as 500 m down the Kobokan drainage on the SE flank during 11-12 January. White-and-gray ash plumes rose 300 m during 14-15 January. At 1020 on 16 January a collapse from the end of the active lava flow in the Kobokan drainage produced a pyroclastic flow, and an ash plume that rose 1.5 km and drifted N. An eruptive event at 0534 on 17 January generated an ash plume that a ground observer reported rising 400 m.

Semisopochnoi – Aleutian Islands (USA) : AVO reported that low-level eruptive activity and elevated seismicity at Semisopochnoi’s North Cerberus cone continued during 12-18 January. A small explosion was recorded by local seismic and infrasound sensors during 12-13 January. The weather was mostly cloudy, though low-level ash clouds were occasionally visible in webcam images during 12-15 January. Steam emissions were visible in 15-16 January webcam images.

Sheveluch – Central Kamchatka (Russia) : KVERT reported that a thermal anomaly over Sheveluch was identified in satellite images during 8-14 January. Intense steam-and-gas emissions with ash were visible during 6-7 and 9-11 January; plumes rose as high as 5 km (16,400 ft) a.s.l. and drifted 175 km W.

Suwanosejima – Ryukyu Islands (Japan) : JMA reported that incandescence at Suwanosejima’s Ontake Crater was visible nightly during 10-17 January. There were 157 explosions recorded, producing ash plumes that rose as high as 2 km above the crater rim and ejected material up to 800 m away from the crater. Eruption sounds were heard in Toshima village (4 km SSW). Volcanologists observed ash-and-steam plumes rising from the crater during an overflight on 17 January.

Turrialba – Costa Rica : OVSICORI-UNA reported that incandescence from Turrialba’s West Crater was visible overnight during 15-16 January. Eruptive events were recorded at 2126 and 2132 on 17 January; the second event was stronger and produced an ash-and-gas plume that rose 1 km above the crater. Ashfall and a sulfur odor were reported by residents in Coronado, Tres Rios (30 km SW), Alajuela (50 km W), and Santa Ana (46 km WSW). At 1115 on 18 January an eruptive event produced a plume that rose 300 m and drifted SW.

Whakaari/White Island – North Island (New Zealand) : On 18 January GeoNet reported results from an overflight of Whakaari/White Island the week before, noting a significant decrease of temperatures at the active vent area and a small decrease in gas emissions. Temperatures in the main vent area were as high as 191 degrees Celsius, a decrease from a high value of 516 measured in December. Gas emissions had slightly decreased since December; both sulfur dioxide and carbon dioxide gas emission rates were slightly below the 10-year average. Both the gas-emission and temperature data were consistent with a degassing magma body below the surface. Very minor ash emissions continued to be visible with deposits only extending around the active vents. The water in the lake had receded likely due to recent dry weather conditions.

Yasur – Vanuatu : The Wellington VAAC reported that on 15 January intermittent low-level ash plumes from Yasur rose 1.5 km (5,000 ft) a.s.l. and drifted SE. Ashfall was reported in nearby villages. A Sentinel satellite image acquired that same day showed a strip of ash deposits in areas to the NW. Continuous, low-level ash plumes were visible in satellite and webcam images on 17 and 18 January rising to 1.5 km a.s.l. and drifting SE and W, respectively.

Volcanos

Roundup of Global Volcanic Activity – New Activity for the week 12 January – 18 January 2022

Barren Island – Andaman Islands (India) : The Darwin VAAC reported that during 1700-2200 on 8 January and 1200-1700 on 9 January ash plumes from Barren Island rose to 1.2 km (4,000 ft) a.s.l. and drifted W and WSW.

Hunga Tonga-Hunga Ha’apai – Tonga Islands : Large eruptions at Hunga Tonga-Hunga Ha’apai on both 14 and 15 January produced plumes that reached the stratosphere and caused significant regional effects. Activity on the 14th apparently removed approximately the middle third of the island that had been expanded over the previous few weeks, revealed by a Planet Lab image acquired at 1525 on 15 January. About two hours after that image was taken an even stronger eruption activity produced a stratospheric plume seen in satellite images, sent pressure waves across the atmosphere, and caused tsunami that traversed the Pacific. Following these explosions, a Sentinel image acquired on 17 January showed that most of the previous combined island had been destroyed, leaving only small parts of the NE island of Hunga Tonga (200 m long) and the SW island of Hunga Ha’apai (700 m long) above the ocean surface.

A sub-aerial eruption that began at 0420 on 14 January produced mushroom-shaped ash, steam, and gas plumes that rose as high as 20 km (65,600 ft) a.s.l., into the stratosphere, and expanded radially at the top of the plume to 240 m in diameter, according to the Tonga Geological Services (TGS). Geologists observing from a boat around 1700-1830 in the afternoon noted that the plume was about 5 km wide at its base, with Surtseyan pulses ejecting dark dense material into the air, and pyroclastic flows expanding over the ocean. The eruption plume drifted over the island groups of Tongatapu, ‘Eua, Ha’apai, and Vava’u, carrying an estimated sulfur dioxide mass of 0.05 Tg (50,000 tonnes) based on satellite data. Sulfur odors were reported in Tongatapu (70 km S), near the capital on Motutapu Island, and on ‘Eua (106 km SSE). Ashfall was reported on many islands, including Fonoi and Mango (75 km ENE). The Tonga Meteorological Services (TMS) issued tsunami warnings for areas including ‘otu Mu’omu’a in Ha’apai (Nomuka, Mango, Fonoifua), ‘Atataa, ‘Eueiki, and Tongatapu mo ‘Eua. At 2000 on 14 January a tsunami with a height of 20 cm was recorded by the Nuku’olofa tide gauge. TMS warned residents to stay away from low-lying coastal areas, beaches, and harbors. The Wellington VAAC noted that the eruption was intermittent during 0043-0604 on 15 January; plumes rose to altitudes of 14 km (45,900 ft) a.s.l. The Global Lightning Detection Network (GLD360) ground-based network detected 191,309 lightning events during a 21-hour period (0334 on 14 January-0134 on 15 January), or up to 30,000 events per hour; for comparison, during 22-28 December 2018 the partial collapse eruption of Krakatau generated 337,000 events. TGS noted that at 0720 on 15 January an eruption lasting 10-15 minutes sent an ash plume to 14 km (45,900 ft) a.s.l. that drifted E.

A larger, submarine eruption began at 1700 on 15 January. According to news reports and social media posts, residents in Nuku’alofa (65 km S) heard multiple loud booms and saw a large expanding eruption plume that eventually covered all of the Tongan islands. According to the Wellington VAAC the plume had risen to 15.2 km (50,000 ft) a.s.l. by 1819; the top of the plume as seen in satellite images was at least 600 km in diameter by 1903. During 1719-2300 there were almost 400,000 lightning events recorded in the plume by the GLD360 network, with 200,000 of those during 1800-1900. By 0343 on 16 January the plume had risen to 19.2 km (63,000 ft) a.s.l. Analysis of other satellite datasets suggested that the plume may have risen to 30 km (98,400) a.s.l. The sulfur dioxide mass of the plume was 0.4 Tg (400,000 tonnes) derived from satellite-based estimates; the cloud drifted W consistent with stratospheric winds. Significant ashfall was reported on populated islands of Tonga, 70-100 km E. News articles noted that some residents had difficulty breathing from the ash in the air.

Most domestic and international communications on the islands were severed due to a break in an underwater cable, and ashfall has delayed both damage assessment and relief assistance. An update on 18 January from the Government of Tonga provided details about the eruption and its effects, noting that tsunami warnings issued after the eruption began had triggered evacuations. Tsunami waves up to 2 m high, based on a news article, arrived on the W coasts of the Tongatapu, ‘Eua, and Ha’apai islands, and three people in Tonga were confirmed to have died as a result, with many others injured. Extensive damage was reported on Mango, Fonoifua, and Nomuka islands, and on the W part of Tongatapu. Aerial surveillance by the New Zealand Defence Force’s showed brown, damaged vegetation and landscapes, debris, and modified coastlines with sediment-laden waters. The Government of Tonga also noted that communications to the outer islands were accomplished with a patrol boat on 17 January, and limited communication with residents of Vava’u and Ha’apai was possible the next day. Evacuation efforts were underway for some remote islands. Ashfall contaminated fresh water supplies, hindered sea transportation and harbor access, and caused flights to be cancelled. According to a news report the small island of Atata, near Nuku’alofa, had been completely submerged. Tsunami warnings were also issued in several other countries surrounding the Pacific Ocean. Several news sources reported flooding and damage caused by the tsunamis at locations as far away as Peru (over 10,000 km), where it caused two deaths. Warnings were issued for the N and E coasts of New Zealand’s North Island and the Chatham Islands; multiple boats were destroyed. Thousands in Japan evacuated after tsunami warnings, and the waves there reached 80 cm, disrupting train services, flights, and damaging harbors and boats. In Anchorage, Alaska, the US National Weather Service reported maximum waves heights of 20-100 cm on Alaskan coastlines, and along the British Columbia coast waves were 16-29 cm on 15 January.

The explosions produced multiple pressure (shock) waves that rippled through surrounding weather clouds, though the pressure wave from the largest explosion propagated across the planet. The sonic boom from this wave was heard at great distances, including in Fiji (about 500 km NW), within about two hours in New Zealand (1,600-2,000 km), and within about nine hours in Alaska, USA (9,370 km NE). The pressure wave was also recorded by infrasound and weather instruments worldwide as it circled the Earth, with instruments picking up the wave a second time as it arrived from the opposite direction. Very small perturbances in the ocean waves recorded in the Caribbean, which some referred to as meteotsunamis, were likely generated by atmospheric disturbances from the pressure waves after they passed over South America.

Piton de la Fournaise – Reunion Island (France) : OVPF reported that the eruption at Piton de la Fournaise continued during 10-16 January. Weather clouds often obscured views of the vent, though visual observations were made daily. Lava was sometimes ejected above the crater rim. The lava lake periodically rose and overflowed the cone during 10-13 January, sending flows down the flanks, and several breakouts of lava were visible on the flow field. The flow on the S margin of the field slowly advanced to the S wall of Enclos Fouqué. Activity decreased for a period of time during 14-15 January. Activity increased again during 15-16 January, though no overflows of the lake were recorded and lava was only periodically ejected above the rim. Some small vegetation fires were visible near the base of the caldera wall. Tremor decreased and the eruption ceased at 0210 on 17 January.

Wolf – Isla Isabela (Ecuador) : On 13 January IG reported that the eruption at Wolf was continuing, but at decreasing levels. Lava from at least three fissures had traveled about 16.5 km SE, and covered an estimated 7.4 square kilometers, but had not reached the coast. Daily counts of thermal anomalies were in the hundreds but had progressively decreased in quantity and intensity in recent days, interpreted as a decrease in the effusion rate and cooling flows. Notices of ash-and-gas plumes were issued by the Washington VAAC on 7-8 January, noting that plumes decreased from 2.6 km to 300 m above the vent. Additionally, sulfur dioxide emissions decreased from 60,000 tons per days recorded on 7 January to 8,100 tons per day on 12 January. Seismicity also trended downward.

Volcanos

Roundup of Global Volcanic Activity – Ongoing Activity for the week 5 January – 11 January 2022

Aira – Kyushu (Japan) : JMA reported that incandescence from Minamidake Crater (at Aira Caldera’s Sakurajima volcano) was visible at night during 3-10 January. An eruptive event at 0143 on 7 January produced an ash plume that rose 1.3 km and ejected bombs 600-900 m away from the crater.

Great Sitkin – Andreanof Islands (USA) : AVO reported that slow lava effusion at Great Sitkin probably continued during 5-11 January, though cloudy conditions prevented satellite and webcam confirmation. Seismicity was very low; several small seismic events were recorded during 9-10 January.

Grimsvotn – Iceland : The Icelandic Meteorological Office (IMO) lowered the Aviation Color Code for Grímsvötn to Green on 12 January, noting that seismicity had returned to normal levels with a few earthquakes detected over the previous few weeks. The caldera had deepened during the jökulhlaup (glacial outburst flood) that had occurred during November and December 2021, though IMO noted that it was difficult to characterize the current status of the caldera and the level of the geothermal activity.

Karymsky – Eastern Kamchatka (Russia) : KVERT reported that a thermal anomaly over Karymsky was visible in satellite images during 2-3 January.

Kilauea – Hawaiian Islands (USA) : HVO reported that lava effusion resumed at the vent in the lower W wall of Kilauea’s Halema`uma`u Crater at around 0400 on 5 January, ending a 3-day pause. The sulfur dioxide emission rate was about 3,300 tonnes per day on 6 January. Lava effused from the vent on most days during 6-11 January, though effusion paused and the lake crusted over for most of the day on 7 January. Several overflows onto older crust were observed after effusion resumed at around 2130 on 7 January through 8 January. The W surface of the lava lake was active during 9-10 January, though there were some more pauses in lava effusion from the W vent during 10-11 January.

Lewotolok – Lembata Island (Indonesia) : PVMBG reported that the eruption at Lewotolok continued during 5-10 January. Variable density white-and-gray ash plumes rose as high as 600 m above the summit and drifted E and SE. Incandescent material was occasionally ejected up to 300 m from the vent and accompanied by rumbling. At 0848 on 11 January an ash plume rose 700 m above the volcano and drifted E.

Merapi – Central Java (Indonesia) : BPPTKG reported no notable morphological changes to Merapi’s summit lava dome, though the dome just below the SW rim had increased about 2 m in height during 31 December 2021 to 6 January 2022. The estimated dome volumes were over 1.67 million cubic meters for the SW dome and just over 3 million cubic meters for the summit dome. The intensity of the seismic signals remained at high levels. As many as 69 lava avalanches traveled a maximum of 2 km SW down the Bebeng drainage.

Pavlof – United States : AVO reported that elevated seismicity at Pavlof during 5-11 January was characterized by daily periods of tremor. High surface temperatures consistent with active lava effusion near the vent were identified in satellite images each day. The lava flow on the SE flank lengthened from 80 to 300 m during 2-6 January based on high-resolution satellite data. Robust steaming was observed by pilots and in webcam images on 9 January.

Rincon de la Vieja – Costa Rica : OVSICORI-UNA reported that multiple eruptive events were recorded at Rincón de la Vieja on 5 January, though most of them were small. A notable explosion at 1833 ejected incandescent material above the crater rim that was visible in webcam images for about 30 seconds. Darkness obscured views of a plume and no ash was visible in satellite images. Residents reported hearing a loud explosion and sounds indicating active lahars; lahars in the Penjamo and Azufrado rivers reached residential areas within 50 minutes of the event. An eruptive event was recorded at 1858 on 10 January, though cloud cover prevented visual confirmation.

Sangay – Ecuador : IG staff observed Sangay during an overflight on 27 December 2021, focusing on the summit area along with the SE and NE flanks. Two vents were active in the summit area, a central vent and a western vent in a scoria cone. The central vent produced Strombolian explosions and had temperatures as high as 645 degrees Celsius. Lava from this vent fed a flow on the SE flank that was 540 m long; the maximum temperature of the flow was 580 degrees. The W vent ejected blocks and gas emissions, and had temperatures as high as 410 degrees. The third vent, on the NE flank, produced gas emissions and temperatures above 515 degrees. A lava flow from this vent had descended 370 m and was as hot as 450 degrees. The team took gas measurements around the summit with a MultiGAS instrument, collected ash samples, and acquired data and conducted maintenance at the SAGA monitoring station, 6 km SW of the summit.

Semisopochnoi – Aleutian Islands (USA) : AVO reported that low-level eruptive activity and elevated seismicity at Semisopochnoi’s North Cerberus crater continued during 4-11 January. Almost daily explosions (one per day during 4-8 January and a few during 10-11 January) were recorded by the local seismic network. The weather was mostly cloudy, though ash and/or steam plumes were occasionally visible in webcam images. Low-level ash clouds were visible in webcam images during 10-11 January.

Sheveluch – Central Kamchatka (Russia) : KVERT reported that a thermal anomaly over Sheveluch was identified in satellite images during 1-7 January. Intense steam-and-gas emissions with ash were visible during 3 and 5-6 January; plumes rose as high as 4 km (13,100 ft) a.s.l. and drifted 180 km N and W.

Suwanosejima – Ryukyu Islands (Japan) : JMA reported that incandescence at Suwanosejima’s Ontake Crater was visible nightly during 3-10 January and 368 explosions were recorded. The explosions produced ash plumes that rose as high as 2 km above the crater rim and ejected material up to 1.1 km away from the crater. Eruption sounds were heard in Toshima village (4 km SSW) and ash fell there during 7-10 January.

Yasur – Vanuatu : The Vanuatu Meteorology and Geohazards Department (VMGD) reported that activity at Yasur continued at a high level of “major unrest,” as defined by the Alert Level 2 status. Ash-and-gas emissions were visible in webcam images at 0845, 0900, 0915 on 7 January rising above the crater rim and drifting NW.

Volcanos

Roundup of Global Volcanic Activity – New Activity for the week 5 January – 11 January 2022

Karangetang – Siau Island (Indonesia). PVMBG reported that incandescence from Karangetang’s N crater was periodically visible during 5-10 January. Daily white emissions rose generally 150 m above the summit, but sometimes as high as 200 m. During 9-10 January white-and-gray plumes rose as high as 200 m.

Krysuvik-Trolladyngja – Iceland : Icelandic Meteorological Office (IMO) reported that the earthquake swarm at the Krýsuvík-Trölladyngja volcanic system that began on 21 December 2021 had ceased. Additionally, InSAR and GPS data last recorded deformation on 28 December.

Piton de la Fournaise – Reunion Island (France) : OVPF reported that the eruption at Piton de la Fournaise continued during 5-11 January 2022. Weather clouds often obscured views of the vent, though visual observations were made daily. Lava fountains sometimes rose above the crater rim. The level of the lava lake periodically rose and overflowed the cone, sending lava flows down the flanks during 6 and 8-9 January. The lava effusion rate was an estimated 2-20 meters per second based on satellite data. Several breakouts of lava from the tube were noted. On 9 January a new lava flow slowly advanced along the S margin of the flow field, reaching 1,800 m elevation. On 10 January hikers observed smoke from an area in the S part of the caldera, likely from vegetation that had been set on fire from lava flows. The flow field continued to widen but had not significantly lengthened.

Semeru – Eastern Java (Indonesia) : PVMBG reported that the eruption at Semeru continued during 5-11 January. Crater incandescence was visible each night. Gray-and-white plumes rose 300-600 m during 4-8 and 10 January. Pyroclastic flows descended the Kobokan (SE) and Lengkong drainages during 5-6 January and avalanches traveled 700 m down the Kobokan drainage during 6-7 January. At 2311 on 7 January a pyroclastic flow traveled 3 km down the Kobokan drainage, and another traveled 1 km down the same drainage during 8-9 January.

Wolf – Isla Isabela (Ecuador) : IG reported that a seismic swarm at Wolf began at 2100 on 6 January, followed by a M 2.4 earthquake recorded at 2135, and tremor at 2315. Fissures opened in an area SE of the summit caldera within five minutes of the onset of tremor and a new eruption began. At 0020 on 7 January satellite images showed ash-and-gas plumes rising to varying altitudes between 1.9 km (6,200 ft) and 3.8 km (12,500 ft) a.s.l., with the lower parts of the plume drifting NE and the higher parts drifting W. Thermal anomalies indicated advancing lava flows down the S and SE flanks. The Parque Nacional Galápagos and the Galapagos Conservancy evacuated eight people by helicopter, including park rangers and scientists that were working near the rim, as a precaution and noted that habitat for a population of critically endangered Pink Land Iguana was far from the eruption. Photos showed a line of lava fountains rising along the fissure and lava flows advancing over vegetation. Thermal anomalies continued to indicate advancing lava during 8-11 January. Plumes mostly consisting of gas rose as high as 1.3 km (4,300 ft) a.s.l. and drifted W and SW. The lava flows were not far from the ocean by 10 January. Photos posted on 11 January by Parque Nacional Galápagos showed lava fountaining at a growing cone and fluid lava flows advancing from the base of the cone. The lava flows had traveled 15 km SE, then E, by 11 January.

Volcanos

Roundup of Global Volcanic Activity – Ongoing Activity for the week 29 December 2021 – 4 January 2022

Aira – Kyushu (Japan) : JMA reported that incandescence from Minamidake Crater (at Aira Caldera’s Sakurajima volcano) was visible at night during 27 December 2021 to 3 January 2022. An eruptive event at 2324 on 28 December produced an ash plume that rose 1.1 km above the crater rim. An eruptive event at 2105 on 1 January 2022 generated ash plumes that rose 1 km and ejected bombs 600-900 m away from the crater.

Davidof – United States : AVO lowered the Volcano Alert Level for Davidof to Unassigned on 31 December, noting that the earthquake swarm that had begun in early December had subsided. The closest seismometers are approximately 15 km E, on Little Sitkin Island. Davidof is also monitored by satellite data and remote infrasound and lightning networks.

Fukutoku-Oka-no-Ba – Volcano Islands (Japan) : The Japan Coast Guard reported that during a 27 December overflight of Fukutoku-Oka-no-Ba, observers noted that the island formed in mid-August had become smaller since 14 December, and had almost eroded below the ocean surface. No eruptive activity was observed, though brownish water spouted from the E end of the island. Yellowish-green water and a string of floating pumice, 400 m long, was circulating 5 km E. Discolored water was visible around almost the entire coast of Minami-Ioto (5 km SSW).

Great Sitkin – Andreanof Islands (USA) : AVO reported that slow lava effusion at Great Sitkin continued during 29 December 2021 to 4 January 2022 along with very low and persistent seismicity. Satellite images acquired on 29 December 2021 and 1 January 2022 showed that the lava flows on the W flanks had advanced.

Ibu – Halmahera (Indonesia) : PVMBG reported that during 31 December 2021 to 4 January 2022 gray-and-white ash plumes from Ibu rose 200-1,000 m above the summit. Avalanches were detected daily, though not visually observed.

Karymsky – Eastern Kamchatka (Russia) : KVERT reported that a thermal anomaly over Karymsky was visible in satellite images during 28-30 December.

Kilauea – Hawaiian Islands (USA) : HVO reported that lava effusion intermittently continued from a vent in the lower W wall of Kilauea’s Halema`uma`u Crater during 29 December 2021 to 4 January 2022. Effusion at the vent paused on the evening of 29 December and the lake mostly crusted over, though lava oozed over the edge of the lake margins in several areas, suggesting a continuing supply of molten lava below the crust. Parts of the crusted lake overturned during 2000-2300. Occasional minor activity at the vent was visible during the morning of 30 December, and lava again began effusing form the vent at 1445. Several large lava overflows of the lake occurred in the evening and bright glow was visible in the evening sky from Volcano to lower Puna. Lava effusion was low during 1-2 January and by 0200 on 2 January the lake once again began to crust over. A large breakout along the N margin of the lake was active. Effusion ceased during 2-4 January; the lake was mostly crusted over except a few overturns N of the vent were noted.

Lewotolok – Lembata Island (Indonesia) : PVMBG reported that the eruption at Lewotolok continued during 31 December 2021 to 4 January 2022. White-and-gray ash plumes that were sometimes dense rose as high as 600 m above the summit. Incandescent material was occasionally ejected from the vent up to 300 m from the vent and rumbling was sometimes heard.

Merapi – Central Java (Indonesia) : BPPTKG reported no notable morphological changes to Merapi’s summit lava dome, though the dome just below the SW rim had decreased about 3 m in height during 24-30 December. The estimated dome volumes were over 1.63 million cubic meters for the SW dome and just over 3 million cubic meters for the summit dome. The intensity of the seismic signals remained at high levels. As many as 175 lava avalanches traveled a maximum of 2 km SW down the Bebeng drainage, and two pyroclastic flows traveled a maximum of 1.8 km SW.

Nevado del Ruiz – Colombia : Servicio Geológico Colombiano’s (SGC) Observatorio Vulcanológico y Sismológico de Manizales reported that during 28 December 2021 to 3 January 2022 seismicity at Nevado del Ruiz was at similar levels to the week before, characterized by periods of continuous volcanic tremor, long-period events, and very-long-period earthquakes, indicating movement of fluids. These earthquakes occurred in the vicinity of Arenas Crater. Additional earthquake signals indicating rock fracturing were located in the SW, SE, and NE parts of the volcano. Several periods of “drumbeat” seismicity, indicting growth of the lava dome, were recorded during 29-30 December and 3 January. Several low-level thermal anomalies were identified in satellite images during the week. The highest gas-and-steam plume rose about 1.2 km above the summit, recorded on 3 January.

Pavlof – United States : AVO reported that seismicity at Pavlof was elevated during 29 December 2021 to 4 January 2022 and was characterized by daily periods of tremor. Minor ash emissions were visible during 28-29 December and small explosions were occasionally recorded during 29-30 December. Thermal emissions continued to be low, and elevated surface temperatures consistent with a hot vent region were identified in satellite images during 1-3 January. During 3-4 January lava was active in an area within 100 m of the SE vent.

Rincon de la Vieja – Costa Rica : OVSICORI-UNA reported that at 1437 on 1 January a small eruption at Rincón de la Vieja produced a plume that rose 50 m above the crater rim. A small eruption was recorded by the seismic network at 0431 on 4 January, though weather clouds prevented visual confirmation. The amplitude of the seismic signal was similar to those recorded for events occurring in the previous few weeks.

Sabancaya – Peru : Instituto Geofísico del Perú (IGP) reported a daily average of 32 explosions at Sabancaya during 27 December 2021 to 2 January 2022. Gas-and-ash plumes rose as high as 2.8 km above the summit and drifted NW, W, and SW. Eight thermal anomalies originating from the lava dome in the summit crater were identified in satellite data. Minor inflation continued to be detected near Hualca Hualca (4 km N).

Semisopochnoi – Aleutian Islands (USA) : AVO reported that low-level eruptive activity and elevated seismicity at Semisopochnoi’s North Cerberus crater continued during 29 December 2021 to 4 January 2022. Minor ash-and-steam emissions were visible in webcam images during 28-29 December. Ash plumes observed in webcam and satellite images on 31 December rose to 1.5 km (5,000 ft) a.s.l. and drifted as far as 100 km NE. Ash emissions observed in webcam images during daylight hours on 1 and 2 January were being blown down the flank by high winds. Small explosions were detected in seismic data during 2-4 January, though cloud cover obscured views.

Sheveluch – Central Kamchatka (Russia) : KVERT reported that a thermal anomaly over Sheveluch was identified in satellite images during 24-31 December. Intense steam-and-gas emissions were visible. Ash plumes rose as high as 4.5 km (14,800 ft) a.s.l. and drifted 110 km NW and NE during 24-25, 27, and 30 December.

Suwanosejima – Ryukyu Islands (Japan) : JMA reported that crater incandescence at Suwanosejima’s Ontake Crater was visible nightly during 27 December 2021 to 3 January 2022. The number of explosions totaled 124. The explosions produced ash plumes that rose as high as 2.2 km above the crater rim and ejected material up to 1.1 km distance from the crater.

Yasur – Vanuatu : On 30 December the Vanuatu Meteorology and Geohazards Department (VMGD) reported that activity at Yasur continued at a high level of “major unrest,” as defined by the Alert Level 2 status. Activity consisted of loud explosions, emissions of steam and ash, and the ejection of bombs that fell inside and around the crater area.

Volcanos

Roundup of Global Volcanic Activity – New Activity for the week 29 December 2021 – 4 January 2022

Ambae – Vanuatu : The Vanuatu Meteorology and Geo-Hazards Department (VMGD) stated that ash-and-gas plumes from Ambae had recently become more noticeable and that residents had reported minor ashfall on roofs and crops. Webcam images showed ash plumes drifting ENE at 1730 and 1830 on 2 January. At 0600 on 3 January an ash-and-steam plume rose 5 km, though only the lower portion of the plume contained ash. At 0730 that same day an ash plume rose almost 1.6 km. The Alert Level remained at 2 (on a scale of 0-5) and the public was warned to stay outside of the Danger Zone defined as a 2-km radius around the active vents in Lake Voui and away from drainages during heavy rains.

Hunga Tonga-Hunga Ha’apai – Tonga Islands : The eruption at Hunga Tonga-Hunga Ha’apai continued intermittently during 29 December 2021 to 4 January 2022, though by 3 January activity had significantly decreased. Several surges of Surtseyan activity, with some periods lasting as long as 30 minutes, occurred during 28-29 December; gas, steam, and ash plumes rose at least to 12.2 km (40,000 ft) a.s.l. and drifted N, though the maximum altitude of the ash-rich portion of the plume was lower. Ashfall was local to areas around the island. Discolored water and rafts of pumice were visible in areas around the island on 30 December, and had been observed since the beginning of the eruption. Steam-and-gas plumes were visible throughout the day, interspersed with occasional tephra ejections. The plumes rose as high as 12 km (39,400 ft) a.s.l. and drifted NNE. During the morning of 31 December intermittent plumes of ash, steam, and gas rose to 3 km (10,000 ft) a.s.l. according to the Wellington VAAC, though the steam-and-gas portion of the plume rose as high as 18 km (59,000 ft) a.s.l. as stated by the Tonga Meteorological Services. The Met Services also noted that ash was no longer visible in the emissions starting around noon. Steam-and-gas plumes were occasional visible in satellite data during 1-2 January. A small ash plume rose 6-7 km (19,700-23,000 ft) a.s.l. during 2220-2230 on 2 January and drifted 10 m NE, dropping in altitude along the way. A cyclone that passed through the area during 3-4 January obscured views of the volcano.

Karangetang – Siau Island (Indonesia) : PVMBG reported that incandescence from Karangetang’s N crater was periodically visible during 31 December 2021 to 4 January 2022. Bluish-white emissions drifted S on 2 January. White-and-gray plumes rose as high as 200 m during 2-3 January.

Krysuvik-Trolladyngja – Iceland : Icelandic Meteorological Office (IMO) reported that the earthquake swarm at the Krýsuvík-Trölladyngja volcanic system was ongoing with more than 19,000 earthquakes recorded during 21-28 December. Earthquakes M 4 or above totaled 14. The number and size of the earthquakes progressively decreased during 29 December 2021 to 3 January 2022; 200 events were recorded during 0000-1535 on 3 January. The seismicity was located along the same dyke system that fed the recent eruption at Geldingadalir.

Nyiragongo – DR Congo : OVG reported that voluminous gas plumes were visible rising from Nyiragongo and crater incandescence was visible during 3-5 January. Lava fountaining and collapses at active vents on the crater floor were observed along with a growing lava lake. Rumbling was sometimes audible.

Piton de la Fournaise – Reunion Island (France) : OVPF reported that the eruption at Piton de la Fournaise continued during 29 December 2021 to 4 January 2022. Weather clouds often obscured views of the vent, though visual observations were made daily. Low lava fountaining, with material rarely rising just above the crater rim, was visible on 29 December. A small mound with a vent that had grown at the base of the main cone was producing gas emissions, and lava advanced through a tube. Lava fountaining was slightly more intense during 30 December 2021 to 3 January 2022, with lava more frequently rising above the crater rim. Several breakouts of lava from the tube were noted downstream of the vent. The lava effusion rate was an estimated 2.3-9 meters per second, with peak rates of 21 meters per second, based on satellite data. Activity at the main cone decreased during 3-4 January. Lava flows within the first 100 m from the cone were an estimated 15 m thick. The flow field continued to widen but had not significantly lengthened.

Semeru – Eastern Java (Indonesia) : PVMBG reported that the eruption at Semeru continued during 29 December 2021 to 4 January 2022. Crater incandescence was visible during the nights of 31 December-4 January. At 0431 on 31 December a pyroclastic flow was generated from the end of the lava flow and an ash plume that rose 2 km above the summit drifted N. A pyroclastic flow descended the Kobokan drainage a maximum distance of 5 km SE on 1 January. Gray-and-white ash plumes rose as high as 800 m above the summit during 3-4 January and drifted in multiple directions. A pyroclastic flow traveled 5 km SE. The Alert Level remained at 3 (on a scale of 1-4). The public was warned to stay at least 500 m away from Kobokan drainages within 17 km of the summit, and other drainages originating on Semeru including the Bang, Kembar, and Sat, due to lahar, avalanche, and pyroclastic flow hazards.

Volcanos

Roundup of Global Volcanic Activity – Ongoing Activity for the week 22 December – 28 December 2021

Aira – Kyushu (Japan) : JMA reported that incandescence from Minamidake Crater (at Aira Caldera’s Sakurajima volcano) was visible at night during 20-27 December. The sulfur dioxide emission rate was 600 tons per day on 20 December. Two eruptive events during 20-24 December produced plumes that rose 1.1 km above the crater rim. Very small eruptive events were detected during 24-27 December.

Great Sitkin – Andreanof Islands (USA) : AVO reported that slow lava effusion at Great Sitkin continued during 21-28 December with advancing lava flows on the N, W, and S flanks. Very low seismicity persisted. Elevated surface temperatures at the summit were detected overnight during 21-24 and 26-27 December; weather clouds prevented observations during 25-26 December.

Karymsky – Eastern Kamchatka (Russia) : KVERT reported that a thermal anomaly over Karymsky was visible in satellite images during 16-21 December.

Kilauea – Hawaiian Islands (USA) : HVO reported that lava effusion intermittently continued at a vent in the lower W wall of Kilauea’s Halema`uma`u Crater during 21-28 December. Effusion paused for a period during 21-22, and sulfur dioxide emissions were 130 tonnes per day during the pause. Strong volcanic tremor began to be recorded at 1930 on 22 December and by 2000 lava again effused from the vent into the rejuvenated a portion of the lake. The lake overflowed and fed substantial lava flows that traveled SE over older crusted parts of the lake all day on 23 December until around midnight. Lava oozed out along the E margins of the lake during 24-25 December, including onto the lowermost down-dropped block from the 2018 caldera collapse, indicating a continuing supply of lava beneath the lake’s crust. The sulfur dioxide emission rate was about 5,300 tonnes per day on 24 December, much higher than during the pause. The surface of the lava lake had begun crusting over on 25 December and by 26 December lava had again ceased erupting from the vent. An area of the lake, 50 m in diameter, to the N of the vent remained molten on 27 December. The sulfur dioxide emission rate was 125 tonnes per day during the pause. Lava again erupted from the vent later that day, beginning at 1930. The lake was incandescent around the vent and lava overflowed the margins, feeding substantial lava flows to the N and S.

Laguna del Maule – Central Chile-Argentina border : SERNAGEOMIN reported that inflation at Laguna del Maule continued in an area SW of the lake during 1-15 December, though deformation had been decreasing since October with a with a maximum rate of 1.88 centimeters per month. Deformation rates during November and December were comparable to those recorded prior to 2019. The number of volcano-tectonic events had also decreased; the largest event was a M 2.3 located 4.1 km ESE from the center of the lake at a depth of 6.1 km.

Lewotolok – Lembata Island (Indonesia) : PVMBG reported that the eruption at Lewotolok continued during 21-25 December. White-and-gray ash plumes that were sometimes dense rose as high as 600 m above the summit. Incandescent material was ejected from the vent up to 300 m in multiple directions. Rumbling, roaring, and booming were often heard.

Manam – Papua New Guinea : The Darwin VAAC reported that a large thermal anomaly over Manam was identified in satellite images during 21-22 December. A discrete ash plume rose to 3.4 km (11,000 ft) a.s.l. and drifted SE on 21 December. Ash plumes may have risen to 10.7 km (35,000 ft) a.s.l. during 0137-0300 on 22 December, though weather clouds and heavy rain obscured satellite views; the plumes were unconfirmed by ground observers. At 1200 on 22 December an ash plume rose to 4.9 km (16,000 ft) a.s.l., drifted E, and dissipated within four hours.

Merapi – Central Java (Indonesia) : BPPTKG reported no notable morphological changes to Merapi’s summit lava dome, though the dome just below the SW rim had increased about 2 m in height during 17-23 December. The estimated dome volumes were over 1.65 million cubic meters for the SW dome and just over 3 million cubic meters for the summit dome. The intensity of the seismic signals remained at high levels. As many as 112 lava avalanches traveled a maximum of 2 km SW down the Bebeng drainage, and four pyroclastic flows traveled a maximum of 2.5 km SW.

Pavlof – United States : AVO reported that seismicity at Pavlof was elevated during 22-28 December and was mainly characterized by periods of sustained tremor and discrete low-frequency events. Numerous small explosions were recorded almost daily, and strongly elevated surface temperatures were visible in satellite images, consistent with lava effusion.

Reventador – Ecuador : IG reported that a high level of activity continued at Reventador during 21-28 December. Gas-and-ash plumes, often observed multiple times a day with the webcam or reported by the Washington VAAC, rose as high as 1.2 km above the summit crater and drifted mainly NW, W, and SW. Crater incandescence was visible nightly, and lava flows were active on the NE and N flanks. Explosions, crater incandescence, and incandescent blocks rolling 500 m down the N and NE flanks were observed at night during 27-28 November.

Rincon de la Vieja – Costa Rica : OVSICORI-UNA reported that at 1015 on 25 December a small eruption at Rincón de la Vieja was recorded for about four minutes but not visually observed due to weather clouds. Rains after the event and continuing early on 26 December washed the acidic sediment deposited from the volcano downstream in the Pénjamo, Azul, and Azufrada drainages, into the aquatic ecosystem. Phreatic events were recorded at 1402 and 1630 on 28 December though weather conditions prevented visual confirmation.

Sangay – Ecuador : IG reported a high level of activity at Sangay during 21-28 December. Seismicity was characterized by daily explosions, long-period earthquakes, and signals indicating emissions. Weather clouds and rain sometimes prevented visual and webcam observations of the volcano, though almost daily ash-and-gas plumes were identified in satellite images by the Washington VAAC or in webcam views; plumes rose as high as 1.5 km above the volcano and drifted SE, S, SW, and W. Multiple (33-73 per day) daily thermal anomalies over the volcano were visible in satellite data. On 25 December volcano observers near Macas reported hearing noises coming from Sangay, possibly due to favorable weather conditions, though the intensity of explosions had slightly increased. Crater incandescence and an active lava flow on the SE flank were visible at night during 27-28 November.

Semisopochnoi – Aleutian Islands (USA) : AVO reported that low-level eruptive activity and elevated seismicity at Semisopochnoi’s North Cerberus crater continued during 22-28 December. Small explosions were detected almost daily in seismic and infrasound data. Low-level ash-and-steam emissions were observed by webcams and in satellite images during 22-25 December, when weather conditions were clear.

Sheveluch – Central Kamchatka (Russia) : KVERT reported that a thermal anomaly over Sheveluch was identified in satellite images during 17-24 December. At 1210 local time on 23 December explosions produced ash plumes that rose to 6 km (19,700 ft) a.s.l. and drifted 70 km NE.

Suwanosejima – Ryukyu Islands (Japan) : JMA reported that crater incandescence at Suwanosejima’s Ontake Crater was visible nightly during 20-27 December. The number of explosions totaled 143 during 22-24 December. Plumes rose as high as 3.1 km above the crater rim and bombs were ejected 700 m from the crater. Explosive activity increased during 24-27 December with explosions totaling 361. Plumes rose as high as 1.5 km and bombs were ejected 800 m form the vent.

Turrialba – Costa Rica : OVSICORI-UNA reported that an area of incandescence on the NW inner wall of Turrialba’s West Crater had been periodically visible at least since mid-November, and was visible during 26-27 December, suggesting that fumarolic temperatures exceeded 300 degrees Celsius. At 0644 on 28 December a one-minute-long eruption produced an ash emission that rose 50 m above the crater rim and drifted W. Another small eruption that produced ash emissions was recorded at 1105 by the seismicity and infrasound networks. The event was heard by authorities in the Parque Nacional Volcán Turrialba.

Yasur – Vanuatu : The Wellington VAAC reported that during 27-28 December ash emissions from Yasur were visible in webcam images rising above the crater rim, to 1.5 km (5,000 ft) a.s.l. Plumes containing ash were not visible in satellite images, though they were also confirmed by Vanuatu Meteorology and Geohazards Department (VMGD).

Volcanos

Roundup of Global Volcanic Activity – New Activity for the week 22 December – 28 December 2021

Ambae – Vanuatu : The Vanuatu Meteorology and Geo-Hazards Department (VMGD) raised the Alert Level for Ambae to 2 (on a scale of 0-5) on 27 December, noting confirmation of a cone that has built up in Lake Voui and increasing activity. A vent in the lake had been emitting steam-and-gas emissions and ejecting wet tephra above the lake’s surface since 5 December.

Hunga Tonga-Hunga Ha’apai – Tonga Islands : The eruption at Hunga Tonga-Hunga Ha’apai that began on 20 December continued through 28 December. According to the Wellington VAAC continuous gas-and-steam plumes with diffuse ash rose 6.1-12.2 km (20,000-40,000 ft) a.s.l. and drifted NE and NNE during 22-23 December, based on pilot observations, satellite images, information from the Tonga Meteorological Office, and weather models. On 22 December Tonga Navy crew sailing near the island recorded Surtseyan explosions ejecting tephra 350 m high. The video confirmed that the vent was in the same area as the 2014 activity. According to a news article plumes of sulfur dioxide spread NNE over the Ha’apai, Vava’u, and Niuatoutapu island groups with the highest concentrations affecting the ‘Otumu‘omu‘a islands on 23 December. Plumes became intermittent by 24 December rising to 10.4 km (34,000 ft) a.s.l. and occasionally as high as 12.2 km. Tonga Geological Services warned the public to stay outside of a 5 km radius of the vents. According to Tonga’s Lead Geologist, satellite images from 25 December showed that the island had grown 300-600 m on the E side, and ash was falling within a 10 km radius. During 25-28 December the gas-and-steam plume rose 9.1-12.2 km (30,000-40,000 ft) a.s.l. and drifted N and NE; the lower part of the plume contained ash and rose as high as 3 km (10,000 ft) a.s.l. Ashfall was confined to the vicinity of the volcano. Tonga Geological Services reported that during 27-28 December clouds of gas and steam drifted E across the ‘Otu Mu’omu’a Islands of Ha’apai at altitudes of 1-18 km (3,300-59,000 ft) a.s.l.; they warned residents to protect water reservoirs because rain may be acidic or contain traces of ash, though the plumes were predominantly drifting at high levels. One flight to Tonga was canceled on 28 December, for the second time since the eruption started.

Krysuvik-Trolladyngja – Iceland : Icelandic Meteorological Office (IMO) reported that the earthquake swarm at the Krýsuvík-Trölladyngja volcanic system was ongoing at least through 26 December. The swarm began at 1800 on 21 December in an area 2-4 km NE of Geldingadalir. Around 3,000 daily earthquakes recorded by the seismic network were mostly located near Fagradalsfjall volcano at depths of 5-8 km, though some were located near the town of Grindavík and lake Kleifarvatn. The swarm was episodic with periods of intense activity. Three earthquakes over M 4 were recorded near Grindavík on 24 December; the largest was a M 4.8. Deformation during 20-26 December was clear in InSAR data, and similar to the deformation observed at the end of February as the dike intrusion was starting near Fagradalsfjall. The seismicity and deformation indicated that magma was moving at depth, likely along the same dyke system that fed the previous eruption at Geldingadalir.

Piton de la Fournaise – Reunion Island (France) : OVPF reported that an eruption at Piton de la Fournaise began at 0105 on 22 December on the S flank, SE of Piton Kala Pélé and SW of Château Fort. Four fissures opened and produced lava fountains, with the lowest point of the eruption at an elevation of 2,000 m. By the evening, the eruption was focused at 2,030 m elevation where a cone was forming around the vent. The lava effusion rate based on satellite data was an estimated 4-7 meters per second, with peak rates of 22 meters per second, during 22-23 December. By 0930 on 23 December the cone was 10 m high and low lava fountains intermittently rose above the crater rim. Lava flowed from an opening at the base of the cone, though a lava tube was beginning to form; lava had descended 2.2 km SSE from the main vent. During 24-25 December lava traveled from the base of the cone hundreds of meters through a tube before it emerged and advanced in a single channel; the front of the flow had advanced slowly, only traveling an additional 300 m by 25 December. During 25-26 December the lava tube broke open and lava was again visible emerging from the base of the cone. The flow rate was between 2 and 27 meters per second, averaging 5 meters per second. A second vent at the base of the cone was visible in the morning of 27 December and lava was again flowing through a tube and then emerging downstream. Lava fountaining continued with material occasionally ejected less than 15 m above the cone during 27-28 December. The effusion rate was an estimated 2-8 meters per second, based on satellite data. The end of the lava flow had not notably advanced since the day before.

Semeru – Eastern Java (Indonesia) : PVMBG reported that the eruption at Semeru continued during 21-28 December. Crater incandescence was visible overnight during 22-23 December and four block avalanches traveled 800 m down the Kobokan drainage on the SE flank. Two pyroclastic flows descended the Kobokan drainage a maximum distance of 5 km. Dense gray plumes rose 500 m above the summit during 23-24 December and three avalanches of material traveled 500 m down the SE flank. At 1706 on 25 December and at 0902 on 28 December ash plumes rose 300 m above the summit and drifted SW and N, respectively. The Alert Level remained at 3 (on a scale of 1-4). The public was warned to stay at least 500 m away from Kobokan drainages within 17 km of the summit, and other drainages originating on Semeru including the Bang, Kembar, and Sat, due to lahar, avalanche, and pyroclastic flow hazards.

Volcanos

Roundup of Global Volcanic Activity – Ongoing Activity for the week 15 December – 21 December 2021

Aira – Kyushu (Japan) : JMA reported that very small eruptive events at Minamidake Crater (at Aira Caldera’s Sakurajima volcano) were detected during 13-20 December. The sulfur dioxide emission rate was slightly high at 1,200 tons per day on 13 December. Crater incandescence was visible at night during 13-17 December.

Fuego – Guatemala : INSIVUMEH reported that 3-13 explosions per hour were recorded at Fuego during 14-21 December, generating ash plumes as high as 1.1 km above the crater rim and periodic shock waves that were felt in communities around the volcano. Ash plumes drifted as far as 40 km NW, W, SW, and SE; ashfall was reported in areas downwind, including Morelia (9 km SW), Panimaché I and II (8 km SW), Santa Sofía (12 km SW), El Porvenir (8 km ENE), San Pedro Yepocapa (8 km NW), Sangre de Cristo (8 km WSW), finca Palo Verde, Santa Sofía (12 km SW), and Yucales (12 km SW) during 16-18 and 20-21 December. Block avalanches descended the Ceniza (SSW), Seca (W), Trinidad (S), Taniluyá (SW), and Las Lajas (SE) drainages, often reaching vegetated areas. Explosions ejected incandescent material up to 100-300 m above the summit during 14-15 and 17-19 December. Winds lifted “curtains” of ash around the volcano during 18-19 December, and crater incandescence was visible overnight during 20-21 December.

Great Sitkin – Andreanof Islands (USA) : AVO reported that slow lava effusion at Great Sitkin likely continued during 15-19 December and very low seismicity persisted. A radar image acquired during 14-15 December showed a growing flow field with lava lobes advancing down the N, W, and S flanks. Elevated surface temperatures at the summit were detected overnight during 15-16 and 18-19 December.

Karymsky – Eastern Kamchatka (Russia) : KVERT reported that a thermal anomaly over Karymsky was visible in satellite images during 11, 13, and 15-16 December.

Kilauea – Hawaiian Islands (USA) : HVO reported that lava effusion continued at a vent in the lower W wall of Kilauea’s Halema`uma`u Crater during 14-20 December. The sulfur dioxide emission rate was about 1,400 tonnes per day on 16 December. By 19 December the lake had risen a total of 69 m since the beginning of the eruption. A series of partial overturns of the lake was visible on 20 December, though by the next morning there was no lava effusion from the vent and the lake had crusted over.

La Palma – Spain : Observations at La Palma on 15 December showed no lava flowing from vents at the W base of the main cone, from tubes, or at the lava delta in the Las Hoyas area. During 15-20 December tremor levels were at background levels and seismicity was very low at all depths. Sporadic gas emissions rose from the vents and from cooling lava flows. Small collapses from the walls of the main and secondary cone craters were visible through the week. Sulfur dioxide levels varied between extremely low and medium values (less than 5 to 999 tons per day) consistent with a cooling and degassing lava flow field. Even though air quality levels had improved overall, a few measurements of diffuse carbon dioxide emissions showed levels around 9 times average background. Authorities warned the public to exercise caution in areas surrounding the flow field due to volcanic gases in the area and noted that lava flows, although cooling, remained at high temperatures.

Lewotolok – Lembata Island (Indonesia) : PVMBG reported that the eruption at Lewotolok continued during 14-21 December. White, gray, and black ash plumes that were sometimes dense rose as high as 1 km above the summit. Incandescent material was ejected from the vent up to 300 m often to the E and SE, but sometimes in all directions. Rumbling and booming sounds were often heard.

Manam – Papua New Guinea : The Darwin VAAC reported that a thermal anomaly over Manam was identified in satellite images on 15 December, prior to an ash emission that rose to 6.1 km (20,000 ft) a.s.l. and drifted SW. An ash plume rising to the same altitude was visible in satellite images on 16 December but had dissipated by mid-morning. Later that day diffuse ash plumes rising to 2.4 km (8,000 ft) a.s.l. were visible in satellite images and reported by ground observers, according to RVO. An eruptive event was recorded by the seismic network at 0600 on 17 December; ground observations indicated that an ash plume likely rose to 3 km (10,000 ft) a.s.l. and drifted SE. At 0840 ash emissions identified in satellite images and by observers rose to 3 km, drifted SE, and dissipated within about five hours. At 0220 on 18 December an ash plume rose to 3 km, drifted SE, and again dissipated within about five hours; a thermal anomaly over the summit was visible in the satellite data. At 1600 on 21 December an ash plume rose to 1.5 km (5,000 ft) a.s.l., drifted NE, and dissipated within about three hours. The thermal anomaly persisted.

Merapi – Central Java (Indonesia) : BPPTKG reported no significant morphological changes at Merapi’s lava domes, located just below the SW rim and in the summit crater, during 10-16 December. The estimated dome volumes were almost 1.63 million cubic meters for the SW dome and just over 3 million cubic meters for the summit dome. The intensity of the seismic signals remained at high levels. As many as 116 lava avalanches traveled a maximum of 2 km SW down the Bebeng drainage, and three pyroclastic flows traveled a maximum of 2.2 km SW. At 1643 on 18 December a pyroclastic flow advanced 2 km SW and produced an ash plume that rose 400 m.

Pavlof – United States : AVO reported seismicity at Pavlof was elevated during 14-21 December and was mainly characterized by periods of sustained tremor and discrete low-frequency events. Strongly elevated surface temperatures were visible in satellite images during 14-16 and 18-21 December, consistent with lava effusion. Numerous small explosions were recorded during 19-21 December.

Popocatepetl – Mexico : CENAPRED reported that each day during 14-21 December there were 11-23 steam-and-gas emissions from Popocatépetl that drifted NW, NE, E, and SE.

Santa Maria – Guatemala : INSIVUMEH reported that in recent months the dome in Caliente crater, the active part of Santa María’s Santiaguito lava-dome complex, has grown due to a higher rate of extrusion. Blocky lava descending the W flank of the dome produced block avalanches, though avalanches often descended the flanks in multiple directions. A larger number of volcano-tectonic earthquakes began to be recorded on 11 December simultaneously with increased surficial activity. The lava extrusion rate increased on 16 December at the WSW part of the dome, causing intense incandescence at the dome, an increase in block avalanches on the W, S, and E flanks, and higher gas emissions. On 17 December strong explosions produced ash plumes that rose as high has 2 km above the dome and drifted 30 km W. Strong explosions continued to be recorded though 19 December; explosions were weak during 20-21 December. Ash fell in areas downwind including San Marcos Palajunoj (8 km SW) and Loma Linda (6 km WSW) during 16-18 December. Strong incandescence and block avalanches on the W, SW, and S flanks continued through 21 December.

Semisopochnoi – Aleutian Islands (USA) : AVO reported that low-level eruptive activity and elevated seismicity at Semisopochnoi’s North Cerberus crater continued during 15-21 December. Small daily explosions were detected in seismic and infrasound data. Low-level ash-and-steam emissions were observed daily by webcams and were occasionally identified in satellite images when weather conditions permitted. Elevated surface temperatures were also identified in satellite data during 15-17 and 19-20 December.

Sheveluch – Central Kamchatka (Russia) : KVERT reported that a thermal anomaly over Sheveluch was identified in satellite images during 10-17 December.

Suwanosejima – Ryukyu Islands (Japan) : JMA reported that crater incandescence at Suwanosejima’s Ontake Crater was visible nightly during 13-20 December. The number of explosions increased on 15 December; there were 152 explosions during 13-17 December. Eruption plumes rose as high as 1.2 km above the crater rim and bombs were ejected 800 m from the vent. There were 288 explosions recorded during 17-20 December. Resulting plumes rose as high as 1.9 km above the crater rim and bombs were ejected as far as 800 m from the vent.

Yasur – Vanuatu : The Vanuatu Meteorology and Geohazards Department (VMGD) reported that activity at Yasur increased at around 2100 on 18 December. Thirty minutes later webcam images showed deposits of incandescent volcanic bombs that had been ejected from the crater and landed on the flanks. Ash-and-gas plumes were visible at 1015, 1430, and 1545 on 19 December drifting W.

Volcanos

Roundup of Global Volcanic Activity – New Activity for the week 15 December – 21 December 2021

Fagradalsfjall (Reykjanes Peninsula, Iceland): (23 Dec) The Icelandic Meteorological Office (IMO) detected an increasing trend of seismic activity began yesterday. 18 quakes at regular intervals of 1 to 10 per minute have been recorded located 2-4 km northeast of Geldingadalir followed by a significant rise of seismic energy at about 00:30 local time. 26 quakes during the past 24 hours were recorded with magnitudes of 3 or more. 1400 earthquakes have been detected in total over the last 24 hours, of which the largest quake with a maximum magnitude of 4.9 occurred at 09:23 local time and was widely felt on the SW corner.

Hunga Tonga-Hunga Ha’apai (Tonga, Tonga Islands): Explosive activity continues. Volcanic Ash Advisory Center (VAAC) Wellington warned about a volcanic ash plume that rose up to estimated 40000 ft (12200 m) altitude or flight level 400 and is moving at 10 kts in NE direction. During the explosion a base surge was generated, a common feature of many phreatomagmatic (hydromagmatic) eruptions. Pyroclastic cloud consisting of ash and steam is formed in a ring around the base of the eruption column.

Piton de la Fournaise (La Réunion): (22 Dec) The effusive activity at the volcano continues. A fountaining continues at four fissure vents feeding the lava flows on the southern flanks. A vigorous lava spattering is seen from the lowest fissure opened at 2000 m altitude. The volcanic tremor decreased gradually from 04:30 local time after a sharp peak related to the onset of the eruption.

Volcanos

Roundup of Global Volcanic Activity – Ongoing Activity for the week 8 December – 14 December 2021

Aira – Kyushu (Japan) : JMA reported that incandescence from Minamidake Crater (at Aira Caldera’s Sakurajima volcano) was visible at night during 6-13 December. As many as five eruptive events generated plumes that rose 1.2 km above the crater rim.

Etna – Sicily (Italy) : INGV reported that during 6-12 December activity at Etna was characterized by gas emissions from all summit craters and ash emissions from Southeast Crater (SEC); weather conditions prevented views during most of the week. During 6-7 December Strombolian activity at SEC produced almost continuous ash emissions that dispersed ENE. On 8 December the ash emissions were diffuse and discontinuous, and dissipated near the summit. At 1805 on 13 December a new vent opened at the base of the W wall of the Valle del Bove, at 2,180 m elevation. A lava flow emerged from the vents and descended a few hundred meters.

Great Sitkin – Andreanof Islands (USA) : AVO reported that slow lava effusion at Great Sitkin continued during 8-14 December and very low seismicity persisted. Elevated surface temperatures at the summit, that were sometimes intense, were detected overnight during 10-11 and 13-14 December. A radar image acquired during 12-13 December showed a growing flow field.

Karymsky – Eastern Kamchatka (Russia) : KVERT reported that during 2-3 December explosions at Karymsky generated ash plumes that rose as high as 4.5 km (14,800 ft) a.s.l. and drifted 235 km ENE. A thermal anomaly was visible in satellite images during 2-4, 7, and 9 December. Dates are based on UTC times.

Kilauea – Hawaiian Islands (USA) : HVO reported that lava effusion continued at a vent in the lower W wall of Kilauea’s Halema`uma`u Crater on most days during 8-14 December. The vent contained ponded and sometimes spattering lava that fed the lake through the E part of the W wall cone. The size of the active part of the lake varied, and lava periodically oozed from the cooler, outer margins of the lake onto the lowest of the exposed down-dropped caldera floor blocks. The sulfur dioxide emission rate was about 3,500 tonnes per day on 9 December. The eruption paused on 11 December then resumed at 2100 on 13 December.

La Palma – Spain : The eruption at La Palma continued during 8-13 December, characterized by sporadic Strombolian activity, occasional lava jetting, advancing and sometimes branching lava flows, and daily ash-and-gas emissions. Seismicity was low at depths of 10-15 km and very low at depths of 30-40 km. Volcanic tremor levels were also generally low, though they fluctuated near the end of the week concurrent with explosive activity. During 8-12 December activity at several vents in the central and SE part of the main cone was low, with only sporadic pulses of Strombolian activity and ash emissions. Ash-and-gas plumes rose as high as 3.7 km a.s.l. and drifted SSE, SSW, SW, and W. Very intense gas emissions were recorded during 9-11 December. Small landslides from fractured areas in the upper part of the secondary cone (on the E flank) descended the interior part of the crater as well as the flanks. Lava from the vents moved through tubes towards the western part of the flow field, though two main breakout flows traveled W over older flows. The most active area was along the S margin of flow 9, where 9 and 11 had joined, as lava continued to descend the sea cliff and widen in the area of Las Hoyas. During 11-12 December lobes from the S margins of the flow traveled S over new ground in the Las Norias area. On 12 December several strong pulses of tremor were accompanied by intense Strombolian activity, with the most intense events at 1200 and 1730 and decreased activity during 1300-1700. A small overflow of lava from one of the vents traveled N over older flows. One of the more intense periods produced dense dark ash plumes that rose 6 km a.s.l. and ejected bombs (some several meters in diameter) as far as 500 m away from the vent. New collapses were visible in the main cone, enlarging the crater, and at the secondary cone. During 12-13 December lava continued to travel W through tubes in the central part of the flow field. At the S margins lava filled in uncovered areas between flows 9 and 11. On 13 December tremor levels fluctuated with pulses of intense signals. A period of major explosive activity during 1745-1900 ejected bombs towards the N flank and produced ash-and-gas plumes. At 1820 video showed lava jetting above the vent and incandescent material falling onto the flanks. Activity at the vents quieted afterwards; tremor decreased at 2000 and by 2200 had reached background levels. Gas emissions from the vents were at high levels through 14 December. Lava continued to advance from the W base of the main cone on 14 December, though at a much lower rate compared to the day before. Small breakouts were visible near Montaña Cogote and Las Norias. Gas and ash emissions continued to impact island residents. Daily measurements indicated that sulfur dioxide emissions persisted at “high” levels (between 1,000 and 29,999 tons per day). Suspended ash and high concentrations of volcanic gases, specifically sulfur dioxide, triggered periodic air-quality alerts mostly affecting the W part of the island including Los Llanos de Aridane, El Paso, and Tazacorte; authorities warned residents of affected areas to stay indoors. Residents and essential personnel were often barred from entering the exclusion zones to irrigate crops, gather belongings, and remove ash from streets and buildings, especially in Las Manchas, Las Norias, and La Bombilla. During 12-13 December diffuse carbon dioxide emissions were 6.9-7.2 times average background levels, specifically impacting the La Bombilla area where dead birds were observed.

Lewotolok – Lembata Island (Indonesia) : PVMBG reported that the eruption at Lewotolok continued during 8-14 December. Daily white-and-gray ash plumes that were sometimes dense rose as high as 700 m above the summit, though weather conditions prevented visual confirmation during 11-12 December. Incandescent material was ejected from the vent up to 300 m during 7-11 December, and was accompanied by faint rumbling.

Merapi – Central Java (Indonesia) : BPPTKG reported that Merapi’s lava domes, located just below the SW rim and in the summit crater, had both grown during 3-9 December. The estimated dome volumes were almost 1.63 million cubic meters for the SW dome and just over 3 million cubic meters for the summit dome. The intensity of the seismic signals remained at high levels. As many as 190 lava avalanches traveled a maximum of 2 km SW down the Bebeng drainage. Four pyroclastic flows traveled a maximum of 2.2 km SW.

Pavlof – United States : AVO reported seismicity at Pavlof was elevated during 8-14 December, and weak explosive activity was detected by geophysical sensors during 8-11 and 13-14 December. No ash emissions were visible, though satellite and webcam views were often cloudy. Elevated surface temperatures were visible in satellite images during 11-14 December; a lava flow on the E flank was visible in images during 12-13 December.

Semisopochnoi – Aleutian Islands (USA) : AVO reported that low-level eruptive activity and elevated seismicity at Semisopochnoi’s North Cerberus crater continued during 8-14 December. Several daily explosions were detected in seismic and infrasound data. Small ash clouds drifting at least 185 km SE were identified in satellite images during 8-9 December. Persistent steam emissions occasionally punctuated by ash emissions were visible in webcam views during 10-11 December, and ash emissions were visible the next day even though conditions were mostly cloudy.

Sheveluch – Central Kamchatka (Russia) : KVERT reported that a thermal anomaly over Sheveluch was identified in satellite images during 3-10 December.

Suwanosejima – Ryukyu Islands (Japan) : JMA reported that crater incandescence at Suwanosejima’s Ontake Crater was visible nightly during 6-13 December. No explosions were detected by the seismic network, though eruption plumes rose 1-3.4 km and material was ejected 400-700 m away from the crater. Ashfall was reported in Toshima village (4 km SSW).

Whakaari/White Island – North Island (New Zealand) : GeoNet reported results from a 10 December overflight of Whakaari/White Island, noting a significant increase of temperatures at the active vent area. Temperatures in the main vent area were as high as 516 degrees Celsius, an increase from the range of 202-264 degrees Celsius measured in both September and November; temperatures over 500 degrees Celsius were last recorded during July-August. Very minor ash emissions continued to be visible with deposits only extending around the active vents. Gas emissions had possibly decreased, though measurements had not been taken since 18 November. The water in the lake has receded likely due to recent weather conditions.

Volcanos

Roundup of Global Volcanic Activity – New Activity for the week 8 December – 14 December 2021

Awu – Sangihe Islands (Indonesia) : PVMBG reported that volcanic seismicity at Awu had increased beginning in October. Notably, the number of shallow volcanic earthquakes increased to 7-26 events per day from the previous maximum of 5 daily events. The number of deep volcanic earthquakes also increased. The Alert Level was raised to 2 (on a scale of 1-4) and the public was warned to stay 1 km away from the summit crater. The report also noted that no emissions nor any other surficial activity had been visible during 1 September-10 December, though weather sometimes hindered views.

Davidof – United States : Earthquake swarms either related to tectonic processes or volcanic unrest were recorded in the vicinity of Davidof during 8-10 December. The largest earthquake was a M 4.2 recorded at 1045 on 10 December. AVO raised the Aviation Color Code to Yellow and the Volcano Alert Level to Advisory due to the possibility of escalating volcanic unrest. Small earthquakes continued to be detected during 11-14 December, though at a lower rate and amplitude. Cloudy or mostly cloudy satellite and webcams views showed no volcanic activity.

Semeru – Eastern Java (Indonesia) : PVMBG reported that lava avalanches from the end of the 700-m-long lava flow on Semeru’s SE flank descended 500 m during 7-8 December. Lava avalanches were detected by the seismic network almost daily during 9-14 December, though weather conditions prevented visual confirmation. During 9-11 December crater incandescence was visible and gray-white ash plumes rose 300-1,000 m above the summit. White plumes rose as high as 1 km above the summit during 12-14 December. According to BNPB, the death toll from the 4 December collapse event rose to 48 by 13 December, 12 people were still missing, 21 were seriously injured, and 9,374 people were in 129 evacuation centers.

Volcanos

Roundup of Global Volcanic Activity – Ongoing Activity for the week 1 December – 7 December 2021

Aira – Kyushu (Japan) : JMA reported that incandescence from Minamidake Crater (at Aira Caldera’s Sakurajima volcano) was visible at night during 29 November-6 December. An eruptive event at 1702 on 2 December generated a plume that rose 1.3 km above the crater rim.

Etna – Sicily (Italy) : INGV reported that during 29 November-5 December eruptive activity at Etna was concentrated at the Northeast Crater (NEC) and the Southeast Crater (SEC), while only minor gas emissions rose from the Voragine and Bocca Nuova craters. Webcam images showed diffuse and discontinuous ash emissions from NEC on 1 December that quickly dissipated near the summit. On the morning of 4 December INGV staff working near the summit observed sporadic and diffuse ash emissions rising from SEC and quickly dissipating around the summit. During the afternoon and through the next day webcam images recorded Strombolian activity at SEC, in addition to the ash emissions.

Fuego – Guatemala : INSIVUMEH reported that 3-12 explosions per hour were recorded at Fuego during 30 November-7 December, generating ash plumes as high as 1 km above the crater rim and periodic shock waves that were felt in communities around the volcano. Ash plumes drifted as far as 25 km SW and W, causing almost daily ashfall in areas downwind, including Morelia (9 km SW), Panimaché I and II (8 km SW), Santa Sofía (12 km SW), El Porvenir (8 km ENE), and San Pedro Yepocapa (8 km NW). Block avalanches descended the Ceniza (SSW), Seca (W), Trinidad (S), Taniluyá (SW), Las Lajas (SE), and El Jute drainages, often reaching vegetated areas. Explosions ejected incandescent material up to 100-200 m above the summit during 30 November-3 December. A new lava flow emerged during the morning of 5 December and lengthened to 400 m by the next day. During 5-6 December explosions ejected incandescent material 100 m above the summit.

Great Sitkin – Andreanof Islands (USA) : AVO reported that slow lava effusion at Great Sitkin likely continued during 1-7 December. Elevated surface temperatures at the summit were periodically detected through the week.

Grimsvotn – Iceland : The Icelandic Meteorological Office (IMO) reported that the jökulhlaup (glacial outburst flood) due to subsidence of the ice shelf in Grímsvötn’s caldera continued until 6 December. Subsidence of the ice shelf into the underlying lake had begun around 24 November in an area SE of Grímsfjall. Water from the lake drained from the E side of Skeiðarárjökull and from a channel in the middle of a trail into the Gígjukvísl River, causing rising waters first detected in that river overnight during 30 November-1 December. By 2 December the flow rate in the river was 930 meters per second, triple what was detected three days before, and 10 times the normal seasonal rate. Daily measurements showed that the flow rate continued to rise, likely peaking at 2,800 meters per second during the morning of 5 December; a second measurement later that day showed a lower discharge rate of 2,310 meters per second. The ice shelf continued to subside, though more slowly, and water turbulence in the lake had also decreased; the data indicated that the lake was mostly empty of water. A number of detected earthquakes were attributed to subsiding and breaking ice. By 6 December the ice shelf had subsided a total of about 77 m. At 0615 an M 2.3 earthquake was immediately followed by a M 3.6 one minute later. Five more earthquakes were recorded during 1500-2130, though all were below M 1. IMO raised the Aviation Color Code to Orange (the second highest level on a four-color scale) based on the increased seismicity during the previous few days, the larger events that morning, and considerations such as short run-up times seen before previous eruptions, and those past eruptions occasionally following flood events. Seismic tremor had decreased by the next day, and no signs of eruptive activity were indicated in gas or deformation data.

Karymsky – Eastern Kamchatka (Russia) : KVERT reported that on 25 November explosions at Karymsky generated ash plumes that rose as high as 6 km (19,700 ft) a.s.l. and drifted 30 km NW. A thermal anomaly was visible in satellite images during27-29 November. Explosions on 2 December produced ash plumes that rose up to 4 km (13,100 ft) a.s.l. and drifted 100 km ENE. Dates are based on UTC times.

Kilauea – Hawaiian Islands (USA) : HVO reported that lava effusion continued at a vent in the lower W wall of Kilauea’s Halema`uma`u Crater during 1-2 December. The rate of effusion sharply decreased, along with volcanic tremor levels, during 1600-1800 on 3 December. A small part of the vent cone collapsed at around 1700. No surface activity was observed on 5 December and most of the next day though weather conditions hindered visual confirmation; a few small hotspots around the vent were visible in thermal camera images. Lava was visible in the vent at about 1730 on 6 December and within 30 minutes was flowing into the lake. By 0300 on 7 December lava had covered the prior extent of the lava lake.

La Palma – Spain : he eruption at La Palma continued during 1-7 December, characterized by Strombolian explosions and lava fountaining/jetting from multiple existing and new vents, advancing and sometimes branching lava flows, and almost daily ash emissions. Seismicity persisted at variable but elevated levels, with earthquake locations distributed at depths of 10-15 km and 30-40 km. Seismicity was intense at both levels during 30 November-2 December, though the intensity at deeper levels began to wane; in general, earthquake activity was low by the end of the week. Volcanic tremor levels fluctuated at medium to intense levels early in the week but by 3 December were also at low levels. Several vents in the main cone continued to effuse lava, eject tephra, and emit ash-and-gas plumes. Lava moved W through pre-existing lava channels, lava tubes, over older flows, and over new ground, increasing the flow field that consists of overlapping flows (numbered 1-12) and two lava deltas. Persistent Strombolian activity was sometimes intense at the NE-flank vent during 1-3 December, and lava continued to feed flow 8 and the N delta. Lava fountains rose 400-500 m above the vent on 2 December. A new pyroclastic cone had formed around the vent, though it was unstable, and blocks from collapses of parts of it were transported downslope by lava flows. The northernmost flow, flow 12, traveled over new ground in the Fronton area and then rejoined flow 8 downslope. The flows reached part of the Tacande highway on 3 December. The vents in the main cone were quieter, periodically emitting ash and gasses. A N-S-oriented crack opened in an area 100 m S of the main vent, likely from subsidence, because it was not hot or emitting gas. The NE vent was quiet by 4 December. On 3 December a new fissure opened on the SE of the main cone and produced Strombolian activity and fast-moving lava flows that traveled SW, along flow 10. The flow continued to advance W on 4 December, though at a slower rate as it moved over new ground in gaps between flows 3 and 11. Several new vents along an E-W fissure located W of Montaña del Cogote opened at noon on 4 December and produced multiple fast-moving lava flows. The flows descended SW over new ground, crossing into the municipalities of Tazacorte and Los Llanos de Aridane, destroying 60 homes. The flow joined flow 9, reached the sea cliff in the Las Hoyas area by 5 December, and descended the cliff the next day. During 6-7 December lava advanced W through multiple tubes and fed flows 1 and 2, and the S delta. The NE vent was quiet for a few days, but sporadic Strombolian activity and ash emissions had returned. Cracks and fractures in the upper part of the cone were visible. Several vents in the central and SE parts of the main cone also produced sporadic Strombolian activity and ash emissions. By 7 December lava had covered an estimated 11.82 square kilometers. The number of people that had evacuated and were staying in hotels had increased to 537. Gas and ash emissions periodically impacted island residents. Suspended ash and high concentrations of volcanic gases triggered a few air-quality alerts mostly affecting the W part of the island; authorities warned residents in some areas to stay indoors. Residents and essential personnel were occasionally barred from entering the exclusion zones to irrigate crops and remove ash from streets and buildings. Ash-and-gas plumes visible during 1-3 and 6-7 December rose as high as 3.5 km a.s.l.; volcanic plumes drifted W, SW, and SSW all week, away from the airport. Daily measurements indicated that sulfur dioxide emissions persisted at “high” levels, indicating values of 1,000 to 29,999 tons per day.

Lewotolok – Lembata Island (Indonesia) ; PVMBG reported that the eruption at Lewotolok continued during 1-7 December. Daily white-and-gray ash plumes that were sometimes dense rose as high as 800 m above the summit. Incandescent material was ejected from the vent on most days, and up to 300 m during 6-7 December, accompanied by roaring and rumbling. The Alert Level remained at 3 (on a scale of 1-4) and the public was warned to stay 3 km away from the summit crater.

Merapi – Central Java (Indonesia) : BPPTKG reported no notable morphological changes to Merapi’s summit lava dome, though the dome just below the SW rim had decreased about 2 m in height during 26 November-2 December. The estimated dome volumes were 1.61 million cubic meters for the SW dome and almost 2.95 million cubic meters for the summit dome. The intensity of the seismic signals was higher than the week before. As many as 170 lava avalanches traveled a maximum of 2 km SW. Two pyroclastic flows traveled a maximum of 3 km SW on 1 December. In a VONA (Volcano Observatory Notice for Aviation), PVMBG stated that at 2104 on 1 December an ash plume rose 1 km above the summit and drifted E. According to BPPTKG a pyroclastic flow traveled 1.8 km down the Bebeng drainage on the SW flank at 1644 on 6 December. The event lasted two minutes and 40 seconds based on seismic data. The

Pavlof – United States : AVO reported that the eruption at Pavlof continued during 1-7 December, focused at a vent on the upper SE flank. Seismicity remained elevated and several daily explosions were detected using infrasound data. Elevated surface temperatures were observed in satellite data during 1-2 December, though cloud cover often prevented observations. No emissions were visible in mostly cloudy satellite and webcam views during 1-3 December. Minor ash emissions were visible in webcam images on 4 December and, based on webcam images and a pilot observation, the next day a diffuse ash plume rose as high as 3 km (10,000 ft) a.s.l. and drifted tens of kilometers beyond the volcano.

Santa Maria – Guatemala : INSIVUMEH reported that the eruption at Santa María’s Santiaguito lava-dome complex continued during 1-7 December. Avalanches generated by both lava effusion at the WSW part of Caliente dome and collapsing material descended the flanks in multiple directions, often reaching the base of the dome. Periodically the avalanches produced curtains of ash along their paths that dissipated near the volcano. Some of the avalanches were preceded by explosions detected by the seismic network and some were audible several kilometers away. During 2-3 and 6-7 December ash plumes rose 500 m above the summit and drifted 10 km NW and W, causing ashfall in areas downwind including San Marcos Palajunoj (8 km SW) and Loma Linda (6 km WSW). During 3-4 December ash-and-steam plumes rose 900 m and drifted SW and W.

Semisopochnoi – Aleutian Islands (USA) : AVO reported that low-level eruptive activity and elevated seismicity at Semisopochnoi’s North Cerberus crater continued during 1-7 December. Several daily explosions were detected in seismic and infrasound data. Weather clouds sometimes obscured satellite and webcam views of the volcano, though on most days low-level ash-and-steam plumes rising no higher than 1.5 km (5,000 ft) a.s.l. were visible mostly in webcam images. During 3-4 December a diffuse ash plume was identified in a satellite image drifting about 100 km E.

Sheveluch – Central Kamchatka (Russia) : KVERT reported that a thermal anomaly over Sheveluch was identified in satellite images during 26 November-3 December.

Suwanosejima – Ryukyu Islands (Japan) : JMA reported that during 29 November-6 December about 47 explosions at Suwanosejima’s Ontake Crater produced eruption plumes that rose as high as 1.7 km above the crater rim and ejected blocks 600-700 m away from the crater. Plumes from non-explosive events rose as high has 2.3 km. Crater incandescence was visible nightly and ashfall was reported in Toshima village (4 km SSW).

Volcanos

Roundup of Global Volcanic Activity – New Activity for the week 1 December – 7 December 2021

Ambae – Vanuatu : The Vanuatu Meteorology and Geo-Hazards Department (VMGD) reported that steam emissions were visible rising an average of 250 m from Ambae’s Lake Voui during 5-7 December. A still image of video taken from an airplane showed brown water surrounding an active and growing cone that was ejecting wet tephra less than 10 m above the lake’s surface. The Alert Level remained at 1 (on a scale of 0-5) and the public was warned to stay outside of the Danger Zone defined as a 2-km radius around the 2017-2018 active vents in Lake Voui and away from drainages during heavy rains.

Nyiragongo – DR Congo : According to a news article seismic signals at Nyiragongo were dominated by long-period earthquakes during 30 November-5 December. Residents of Goma observed incandescence emanating from the crater on 4 December.

Sangay – Ecuador : IG reported that during 1-2 December activity at Sangay was characterized by increased seismicity, explosions and ash emissions, and a new lava flow on the N flank. The SAGA seismic station, SW of the volcano, recorded a swarm of long-period events beginning at 1600 on 1 December that indicated fluid movements. The amplitude and frequency of the events intensified, and by 2356 the rate had increased from 32 to 60 events per hour. At 0403 on 2 December the SAGA station recorded a major explosion. Based on Washington VAAC advisories two eruption plumes rose 7-10 km above the summit and drifted W, and a third rose almost 1.8 km and drifted NW, though IG noted that the lack of reported ashfall in the nearest towns 25 km away indicated low ash content. Thermal satellite data showed that a new lava flow had emerged on the upper N flank by 2 December.

Semeru – Eastern Java (Indonesia) : PMVBG reported collapses of the lava dome in Semeru’s Jonggring Seloko Crater and SE-flank flow during 1-6 December. On 1 December material collapsed from the unstable distal end of a 1-km-long lava flow in the SE-flank Kobokan drainage, sending a pyroclastic flow 700 m down the valley. Subsequent avalanches were recorded by the seismic network that day and on 3 December were not visually confirmed, likely due to several days of rainy conditions. At 1330 on 4 December the seismic network recorded avalanche signals. A larger collapse began at 1447 was seen by an observer at the Mount Semeru Volcano Observation Post and identified in data collected by PVMBG. Avalanches of incandescent material from the summit dome and SE-flank lava flow descended 500-800 m. Pyroclastic flows were visible at 1510 descending the Kobokan drainage and a sulfur odor was noted. At 1520 a large pyroclastic flow produced a large roiling and expanding ash cloud that eventually rose to 15 km (50,000 ft) a.s.l. Reports from residents described darkness from airborne ash and rainy/foggy conditions. Pyroclastic material was deposited in two districts in the Lumajang regency, and eight districts in the neighboring Malang regency were covered with ash. Preliminary estimates suggested that deposits extended at least 16 km SE from the summit.

According to the Darwin VAAC satellite observations acquired at 1630 showed a detached ash cloud drifting SW at an altitude of 15 km (50,000 ft) a.s.l. At 1740 the ash cloud continued to drift SW and a second ash cloud was drifting W at 9.1 km (30,000 ft) a.s.l. The second ash cloud had detached by 1840. On 5 December satellite images showed the two ash clouds still drifting SW and W, and possible diffuse ash emissions rising to 4.6 km (15,000 ft) a.s.l.; ash had dissipated by 1000.

Following the 4 December pyroclastic flow Badan Penanggulangan Bencana Daerah (BPBD) issued a warning to residents to stay away from drainages due to lahar hazards and began evacuating people in high-risk areas. Ten people trapped in a building could not be reached because of scalding hot deposits but were later rescued. Almost all of the houses in the Curah Kobokan area had been destroyed, mainly by pyroclastic flows, though some residents reported roof collapses from ashfall. One area of Curah Kobokan was inundated by hot lahars that took down trees. Pyroclastic flows also destroyed the Gladak Perak bridge, 13 km SE of the summit, which linked residents of Pronojiwo and Lumajang; the national road leading to Malang was blocked by tephra and fallen trees. According to news articles and BNPB, by the next day 14 people were confirmed to have died, 57 had been injured and taken to hospitals (more than a dozen of were in critical condition due to severe burns), and at least seven residents and sand miners working along the river in Curah Kobokan were missing. About 1,300 people had relocated to evacuation centers or alternative housing.

Additional pyroclastic flows during 5-6 December descended 2-3 km SE, and incandescent avalanches descended 500 m. At 0855 on 6 December a pyroclastic flow traveled 4 km down the SE drainage, temporarily halting rescue and recovery efforts. Later that day, the head of BNPB, police officers, and others conducted a 15-minute overflight of Curah Kobokan and observed steam plumes rising from the deposits. Initial estimates were that 2,970 houses and 38 educational facilities across several sub-districts in Lumajang Regency had been destroyed or damaged by the pyroclastic flows. Authorities also traveled to the fallen bridge and other nearby locations, noting damaged vegetation, fallen trees, and volcanic deposits up to 30 cm thick along the road.

By 7 December an estimated 4,250 residents were displaced in about 20 evacuation centers; most people originating from the Lumajang Regency and fewer from the Malang and Blitar regencies. The number of fatalities reached 34, with another 22 people missing. Search efforts focused on the villages of Renteng, Sumberwuluh, and Kobokan Curah, but daily afternoon rains hampered rescue and recovery efforts.

Volcanos

Roundup of Global Volcanic Activity – Ongoing Activity for the week 24 November – 30 November 2021

Aira ; Kyushu (Japan) : JMA reported that incandescence from Minamidake Crater (at Aira Caldera’s Sakurajima volcano) was visible at night during 22-29 November. An eruptive event at 1509 on 25 November generated a plume that rose 1 km above the crater rim. The sulfur dioxide emission rate was slightly high at 1,200 tons per day on 26 November; sulfur dioxide emissions had been generally high since late September 2020.

Bagana ; Bougainville (Papua New Guinea) : The Darwin VAAC reported that on 27 November ash plumes from Bagana rose to 2.1 km (7,000 ft) a.s.l. and drifted NW based on satellite and wind model data.

Ebeko ; Paramushir Island (Russia) : On 26 November KVERT lowered the Aviation Color Code for Ebeko to Yellow (the second lowest level on a four-color scale), noting that a thermal anomaly was last identified on 25 October and eruptive activity was last recorded on 9 November. Gas-and-steam emission continued to be visible.

Etna – Sicily (Italy) : INGV reported that gas emissions from Etna’s summit craters were visible during 15-21 November, though weather clouds sometimes prevented webcam observations. At 1116 on 20 November an explosion at Northeast Crater (NEC) produced diffuse ash-and-gas plumes that quickly dissipated near the summit.

Great Sitkin – Andreanof Islands (USA) : According to AVO satellite images acquired on 23 November showed that lava effusion at Great Sitkin continued, though at a low rate. Lava continued to fill the summit crater and the flows on the flanks advanced short distances. During 24-30 November seismicity remained slightly above background levels. Elevated surface temperatures were periodically detected.

Grimsvotn – Iceland : On 24 November Icelandic Meteorological Office (IMO) reported that the ice sheet in Grímsvötn’s caldera had subsided 60 cm in the previous few days and the rate of subsidence had accelerated in the last day. By 29 November the ice had sunk a total of 5 m and by 1 December the subsidence totaled 10 m. Data indicated that water had likely begun exiting the caldera and will result in a jökulhlaup (glacial outburst flood) that will cause flooding conditions in drainages. Water levels in the Gígjukvísl drainage rose overnight during 30 November-1 December.Roads, including several national highways, have been cut by flooding or landslides. Wide areas of agriculture along with livestock have suffered damage.

Katmai – United States : AVO reported that on 25 November strong winds in the vicinity of Katmai and the Valley of Ten Thousand Smokes blew unconsolidated ash SE over Shelikof Strait and Kodiak Island at an altitude up to 1.5 km (5,000 ft) a.s.l. The ash was originally deposited during the Novarupta eruption in 1912.

Kilauea – Hawaiian Islands (USA) : HVO reported that the summit eruption at Kilauea continued at a vent in the lower W wall of Halema`uma`u Crater during 24-30 November. The vent contained ponded and sometimes spattering lava that fed the lake through the E part of the W wall cone. The size of the active part of the lake varied, and lava periodically oozed from the cooler, outer margins of the lake onto the lowest of the exposed down-dropped caldera floor blocks. Earthquake activity remained below background levels and volcanic tremor was elevated. The sulfur dioxide emission rate had averaged 3,000 tonnes per day in recent weeks; on 23 November the rate was higher at 6,400 tonnes per day and on 29 November it was below the average at 1,200 tonnes per day.

La Palma – Spain : The eruption at La Palma continued during 24-30 November, characterized by Strombolian explosions and lava fountaining/jetting from multiple existing and new vents, advancing and sometimes branching lava flows, and daily ash emissions. The eruption began on 19 September and had been active for 70 days by 28 November. Volcanic tremor levels were low, though during 28-29 November levels fluctuated and were sometimes intense. Seismicity persisted at variable but elevated levels, with earthquake locations distributed at depths of 10-15 km and 30-40 km. Deeper seismicity decreased to low levels by 27 November while mid-level seismicity intensified through the week. The largest earthquake was a M 5 recorded at 0935 on 29 November at a depth of 36 km. A M 4.2 earthquake at a depth of 13 km was the largest event at mid-levels since the eruption began. Several vents in the main cone continued to effuse lava, eject tephra, and emit ash-and-gas plumes. Lava moved W through pre-existing lava channels, lava tubes, over older flows, and over new ground, increasing the flow field that consists of overlapping flows (numbered 1-11) and two lava deltas. During 23-25 November flows 4, 5, and 7 at the N end of the flow field continued to widen and advance, filling in gaps between the flows, and fed the N delta. Flows 1, 2, and 9 minimally fed the S delta. There was also an increasing number of active flows on the flow field as lava overflowed some channel margins or broke out of tubes. At around 0900 on 25 November the lava effusion rate increased at main crater vents, and around 1100 two small E-W fissures opened less than 1 km S of the main cone. The easternmost vent produced a fast-moving lava flow that traveled along the S margin of flow 10 and around the S side of Montaña Cogote. The flow advanced through the Las Manchas cemetery and inundated parts of a solar power plant; the newly covered areas were part of the exclusion zone and had already been evacuated. The flow rate slowed to about 25 m per hour and joined flow 11 by 26 November. An overflow of lava SW of flow 3 produced a small branch oriented laterally the flow margin. Flow 7 widened during 26-27 November as it continued to be fed. New vents opened on the NE flank of the main cone at around 0300 on 28 November, producing fluid lava flows that traveled N and NW through the Tacande area and crossed the LP-212 road. The opening of the new vents was followed by landslides on the NW flank of the cone. In a video taken at 1145 lava fountains rose from one of the vents while another ejected tephra. Dense billowing ash plumes rose from the main crater. Video taken at 1050 on 29 November showed lava flows transporting large blocks downslope. Another video showed lava flowing at a rate of about 1 m per second. By noon the vents in the main cone became notably less active and remained only intermittently active through 30 November. Several streams of lava from the new vents continued to advance NW and then W along older flows and split into two branches. One branch traveled through tubes and fed flows 4, 5, and 7 between Montaña de Todoque and Montaña de La Laguna and the other descended towards flow 8 (the most northern flow). Flows inundated previously untouched forest and agricultural land. By 30 November the width of the flow field had grown to 3.35 km and lava covered an estimated 11.34 square kilometers. The number of people that had evacuated and were staying in hotels had increased to 537. Gas and ash emissions again impacted island residents. Suspended ash and high concentrations of volcanic gases triggered a few air-quality alerts mostly affecting the W part of the island; authorities warned residents of some affected areas to stay indoors. Essential personnel were occasionally barred from entering the exclusion zones to irrigate crops and remove ash from streets and buildings. Heavy rains during 25-26 November triggered warnings from authorities to stay away from steep slopes and drainages due to the possibility of lahars. Ash plumes rose as high as 4.8 km and drifted E during 24-26 November, and continued to deposit ash at La Palma airport. By 27 November winds had shifted and the ash at the airport had been removed, allowing it to open for the first time since 20 November. Ash plumes rose 1.4-3.5 km and drifted SW and SSW during the rest of the week. Sulfur dioxide emissions continued an overall downward trend during 23-26 November, though heavy rain sometimes prevented ground-based measurements. The trend was broken on 27 and 28 November with values of 30,000-49,999 tons per day, characterized as “very high.” During 29-30 November emission values were “high” or between values of 1,000 and 29,999 tons per day.

Lewotolok – Lembata Island (Indonesia) : PVMBG reported that the eruption at Lewotolok continued during 24-30 November. Daily white-and-gray ash plumes rose as high as 1 km above the summit. Crater incandescence was visible each day, with eruptions accompanied by rumbling and roaring sounds. Incandescent material was ejected 300-500 m E and SE from the vent during 24-25 November.

Merapi – Central Java (Indonesia) : BPPTKG reported no notable morphological changes to Merapi’s SW lava dome, located just below the SW rim, or the dome in the summit crater during 19-25 November. The estimated dome volumes remained stable at 1.61 million cubic meters for the SW dome and almost 2.93 million cubic meters for the summit dome. As many as 110 lava avalanches traveled a maximum of 2 km SW. One pyroclastic flow traveled 1.8 km SW on 20 November.

Nyiragongo – DR Congo : OVG reported that active vents on the crater floor of Nyiragongo were seen ejecting spatter on 27 November.

Pavlof – United States : AVO reported that the eruption at Pavlof continued during 23-30 November, focused at a vent on the upper SE flank. Low lava fountaining that had begun on 14 November continued to construct an unstable cone over the vent. Hot rubbly lava flows from the cone traveled a few hundred meters down the flanks, melting snow and ice that resulted in narrow lahars which traveled several kilometers down the flanks; satellite data from 25 November showed a new debris flow extending downslope from the end of the lava flow. Seismicity remained elevated; a few small explosions were detected during 24-26 and 28-30 November. Elevated surface temperatures were periodically observed in satellite data, though cloud cover sometimes prevented observations.

Reventador – Ecuador : IG reported that a high level of activity continued to be recorded at Reventador during 24-30 November. Gas-and-ash plumes, often observed multiple times a day with the webcam or reported by the Washington VAAC, rose higher than 1.3 km above the summit crater and drifted mainly NW, W, SW, and S. Crater incandescence was visible nightly, and incandescent blocks were observed rolling 400 m down the flanks in all directions on most nights.

Sangay – Ecuador : IG reported that thermal anomalies, persistent at Sangay since July, suggested continuous emission of lava flows and hot pyroclastic material from summit crater vents. The SE drainage, which had been scoured and widened by persistent pyroclastic flows during August 2019 to March 2020, had only widened from about 600 m to about 650 m during March-October. An increased number of explosions and an inflationary trend were recorded during the previous few weeks. Strombolian activity began to dominate the eruptive style in July, though on 17 November the number of explosions increased to two per minute and remained at that level at least through 23 November. Most of the explosions were small and were recorded both by the seismic and acoustic networks. Though slight inflation began to be detected in June 2021 the trend was more pronounced in recent weeks. InSAR satellite data showed an inflationary trend of up to 5 cm per year all around the volcano except the E flank between 5 January 2020 and 13 November 2021. The sulfur dioxide emission rate had remained stable and low since June, with values less than 1,000 tons per day. Daily ash-and-gas plumes were identified by the Washington VAAC or in IG webcam views during 23-29 November. The plumes rose 970-2,100 m above the volcano and drifted NW, W, SW, and S. Daily thermal anomalies over the volcano were often visible in satellite data. Strombolian activity at summit vents and SE-descending lava flows were visible during 23-24 November. A new vent was possibly identified on the upper W flank. Two lahars were detected by the seismic network on 25 November.

Semisopochnoi – Aleutian Islands (USA) : AVO reported that eruptive activity at Semisopochnoi’s North Cerberus crater continued during 24-30 November. Daily minor explosions were detected in seismic and infrasound data. Weather clouds obscured satellite and webcam views of the volcano on most days; small ash plumes rising no higher than 3 km (10,000 ft) a.s.l. were sometimes visible during breaks in the cloud cover but were likely emitted daily.

Sheveluch – Central Kamchatka (Russia) : KVERT reported that a thermal anomaly over Sheveluch was identified in satellite images during 19-26 November.

Stromboli – Aeolian Islands (Italy) : INGV reported that during 15-28 November activity at Stromboli was characterized by ongoing explosive activity from five vents in Area N (North Crater area) and four vents in Area C-S (South-Central Crater area). Explosions from Area N vents (N1 and N2) averaged 6-17 events per hour; explosions from two vents in the N1 vent ejected lapilli and bombs 80 m high and explosions at three N2 vents ejected material 80-150 m high. Spattering at N2 was sometimes intense. No explosions occurred at the S1 and C vents in Area C-S; explosions at the two S2 vents occurred at a rate of 4-9 per hour and ejected coarse material as high as 80 m. Drone footage acquired on 20 November captured two C-S vents ejecting shreds of lava and one emitting gas. A 60-m-line of fumaroles, oriented NNW, were situated on the Sciara del Fuoco, down-flank of Area N. During the morning of 21 November intense spattering occurred at a vent between N1 and N2 produced a rheomorphic lava flow, formed by the accumulated spatter, on the upper middle part of the Sciara del Fuoco. At 0751 on 25 November lava blocks originating from a hornito in the N2 area began rolling downslope. Within a few hours a lava flow was visible in the same area; blocks from the end of the flow descended the Sciara del Fuoco, reaching the coastline. The rate of lava effusion varied during 25-26 November; the flow had begun cooling by the evening of 27 November.

Suwanosejima – Ryukyu Islands (Japan) : JMA reported that during 22-29 November about 41 explosions at Suwanosejima’s Ontake Crater produced eruption plumes that rose as high as 2.7 km above the crater rim and ejected blocks 500-800 m from the crater. Crater incandescence was visible nightly.

Yasur – Vanuatu : The Vanuatu Meteorology and Geohazards Department (VMGD) and the Wellington VAAC reported that multiple gas-and-ash emissions at Yasur were visible in webcam images on 27 November rising 1.5-1.8 km (5,000-6,000 ft) a.s.l. and drifting W. Weather clouds prevented satellite observations of the emissions.