Volcanos

Roundup of Global Volcanic Activity – Ongoing Activity for the week 13 October – 19 October 2021

Aira – Kyushu (Japan) : JMA reported that incandescence from Minamidake Crater (at Aira Caldera’s Sakurajima volcano) was visible at night during 11-18 October. The sulfur dioxide emission rate was 800 tons per day on 11 October. A very small eruptive event was recorded on 14 October.

Bagana – Bougainville (Papua New Guinea) : The Darwin VAAC reported that on 14 October an ash plume from Bagana rose to 2.1 km (7,000 ft) a.s.l. and drifted NE based on satellite and wind model data.

Ebeko – Paramushir Island (Russia) : According to volcanologists in Severo-Kurilsk (Paramushir Island), about 7 km E of Ebeko, an explosion on 10 October produced an ash plume that rose as high as 2.5 km (8,200 ft) a.s.l. and drifted NE.

Erta Ale – Ethiopia : During 15 September-15 October satellite data showed thermal anomalies of variable intensities in Erta Ale’s S pit crater and occasional thermal anomalies at the N pit. An anomaly was detected in the N, NW, and W parts of the N pit crater on 15 October.

Great Sitkin – Andreanof Islands (USA) : AVO reported that lava effusion continued at Great Sitkin during 13-19 October. Seismicity remained elevated and was characterized by small earthquakes consistent with lava effusion, though an outage affected geophysical data streams during 16-18 October. Satellite images acquired on 11 October showed that lava filled more than half of the summit crater, flowing onto the S and W flanks, and had recently reached the N crater rim. Lava traveled 330 m down the S flank, 350 m down the W flank, descended small valleys, and in some areas, advanced over snow and ice. Blocks that had detached from the end of the W flow descended 450 m.

Karymsky – Eastern Kamchatka (Russia) : A thermal anomaly over Karymsky was identified in satellite images during 8-9 October. On 19 October KVERT lowered the Aviation Color Code to Yellow (the second lowest level on a four-color scale), noting that only gas-and-steam emissions persisted after the last ash explosions were recorded on 25 September. On 20 October explosions generated ash plumes that rose as high as 4 km (13,100 ft) a.s.l. and drifted almost 90 km ENE.

Kavachi – Solomon Islands : Satellite data showed discolored water around and to the SW of Kavachi on 12 October. Discolored water was not obviously visible in images from 2, 7, and 17 October.

Krysuvik-Trolladyngja – Iceland : Icelandic Meteorological Office (IMO) reported that during 18 September-18 October no lava effusion was detected at the Krýsuvík-Trölladyngja volcanic system. The seismic swarm that had begun on 26 September in an area SW of Keilir (about 10 km NE of the fifth vent), at the N end of the dike intrusion, had significantly decreased in mid-October. The Aviation Color Code was lowered to Yellow (the second lowest level on a four-color scale) on 18 October. IMO noted that gas emissions were ongoing, though with very low concentrations of eruptive gases. Minor thermal anomalies were detected less often; incandescence from previously emplaced lava flows was occasionally visible at night. IMO also stated that residual heat, gases, and incandescence may continue for weeks to months.

Lewotolok – Lembata Island (Indonesia) : PVMBG reported that the eruption at Lewotolok continued during 13-19 October. White, gray, and black plumes generally rose as high as 1 km above the summit and drifted in multiple directions. Rumbling and banging sounds were reported almost daily. Incandescent material was ejected most days as far as 100 m from the vent and as high as 300 m above the vent.

Merapi – Central Java (Indonesia) : BPPTKG reported minor morphological changes to Merapi’s SW lava dome, located just below the SW rim, and the dome in the summit crater during 8-14 October. The SW dome grew about 2 m taller and had an estimated volume of 1.61 million cubic meters, while the summit lava dome grew about 4 m taller had an estimated volume of 2.93 million cubic meters. As many as 41 lava avalanches traveled a maximum of 2 km SW.

Pavlof – United States : AVO reported that the eruption at Pavlof continued during 13-19 October and was focused at a vent on the upper SE flank, near the location of the 2007 vent. Seismicity remained elevated. Two small explosions were recorded in infrasound and seismic data on both 14 and 16 October. A few explosions were recorded during 17-18 October; ash deposits on the flanks were visible in satellite images. Cloudy conditions obscured satellite and webcam images most days.

Rincon de la Vieja – Costa Rica : OVSICORI-UNA reported that at 0750 on 13 October an eruption at Rincón de la Vieja produced a plume that rose 500 m above the crater rim and drifted SW. Fumarolic activity inside the crater was visible during 14-15 October.

Semeru – Eastern Java (Indonesia) : PVMBG reported that gray-and-white emissions rose 200-500 m above Semeru’s summit and drifted SW, W, and N during 12-13 and 15-16 October. Weather clouds often prevented visual observations of the summit.

Semisopochnoi – Aleutian Islands (USA) : AVO reported that eruptive activity at Semisopochnoi’s North Cerberus crater continued during 13-19 October. Seismicity remained elevated and daily minor explosions were detected in infrasound data. Although weather clouds often prevented webcam and satellite views, intermittent, low-level ash emissions were visible rising to altitudes up to 3 km (10,000 ft a.s.l.) and drifting E on 13 October. Ash plumes rose as high as 1.5 km (5,000 ft) a.s.l. on 18 October.

Sheveluch – Central Kamchatka (Russia) : KVERT reported that a thermal anomaly over Sheveluch was identified in satellite images during 8-15 October.

Suwanosejima – Ryukyu Islands (Japan) : JMA reported that 13 explosions at Suwanosejima’s Ontake Crater produced eruption plumes that rose as high as 2.7 km above the crater rim during 11-18 October. Large volcanic bombs were ejected 500-700 m from the crater. Ashfall was reported in Toshima village (4 km SSW).

Taal – Luzon (Philippines) : PHIVOLCS reported that upwelling of hot volcanic fluids in Taal’s crater lake was visible during 13-18 October, and gas-and-steam plumes rose 1.2-3 km above the lake and drifted in multiple directions. Sulfur dioxide emissions averaged 6,393-12,611 tonnes/day, though on 15 October the emissions peaked at 23,576 tonnes/day, which was the second highest ever sulfur dioxide gas flux recorded at the volcano. Dense vog spread over the Taal Caldera region was noted on 15 October. Earthquake activity resumed on 11 October after a brief lull that first began on 27 September; 145 events characterized as mostly weak low-frequency earthquakes and volcanic tremor were recorded during 11-15 October. Volcanic tremor persisted through 18 October.

Whakaari/White Island – North Island (New Zealand) : On 18 October GeoNet reported results from a recent overflight of Whakaari/White Island. Gas measurements showed that sulfur dioxide emissions had decreased from 520 tons per day recorded at the end of September to 267 tons per day. Temperatures in the main vent area were as high as 220 degrees Celsius, similar to temperatures measure two weeks prior. Minor ash deposits from intermittent ash emissions were visible in the area close to the active vents. Seismicity was characterized by low levels of volcanic tremor and occasional low-frequency volcanic earthquakes.

EWCOLOR

A drone image captured the lava flow from Spain’s Cumbre Vieja volcano which destroyed parts of a banana plantation on La Palma and increased the size of the country as it flowed into the sea, creating new land.

Volcanos

Roundup of Global Volcanic Activity – New Activity for the week 13 October – 19 October 2021

Asosan – Kyushu (Japan) : According to JMA the number of volcanic tremor signals at Asosan began on 12 October. Tremor amplitude began increasing at 1530 on 13 October, prompting JMA to raise the Alert Level to 2 (on a scale of 1-5) almost two hours later. White plumes rose 1.4 km above Nakadake Crater. An eruption was detected at 0443 on 14 October; weather clouds prevented visual confirmation of an eruption plume, though ejected incandescent material was visible in thermal camera images. During a field visit to the volcano later that day, scientists confirmed ashfall in several areas, including parts of Takamori Town (Kumamoto Prefecture), Taketa City (Oita Prefecture), and Takachiho Town (Miyazaki Prefecture). Small eruptive events occurred at 1057 and 1325 on 15 October. Volcanic tremor amplitude increased at 1400 on 18 October. During an overflight scientists observed ash deposits extending SE from Nakadake Crater. Volcanic tremor amplitude continued to fluctuate at high levels on 19 October. At 1143 on 20 October a notable eruption ejected blocks 900 m S and produced an ash plume that rose 3.5 km above the crater rim and drifted E. Pyroclastic flows descended 1.3 km W.

Kilauea – Hawaiian Islands (USA) : HVO reported that the summit eruption at Kilauea continued in Halema`uma`u Crater during 12-19 October. A 10-m-wide, horseshoe-shaped spatter rampart had formed around the W vent and was open to the E where lava was feeding the lake. For about 10 hours on 12 October a new vent N of the W vent produced 10-15-m-high lava fountains. Lava fountains from the W vent rose as high as 20 m and fed the lava lake which was 46 m deep by 18 October. The lava lake was not level with the deepest parts measured around the W vent; the W end was 4-5 m higher than the N and S parts of the lake and 12 m higher than the E end. Cooled and crusted parts of the lake’s surface overturned, or “foundered,” in all parts of the lake except the E part. The sulfur dioxide emission rate was high at 1,600-6,800 tonnes per day during 12-14 and 16-17 October.

Manam – Papua New Guinea : RVO reported that sporadic small ash emissions from Manam’s Southern Crater were observed starting at the end of September. Nighttime incandescence began on 8 October and incandescent material was occasionally ejected from the crater. The activity was characterized as moderately Strombolian with incandescent material rolling down SW Valley, visibly appearing as short lava flows. The Darwin VAAC noted that on 18 October an ash plume rose to 2.4 km (8,000 ft) a.s.l. and drifted NW. A thermal anomaly was visible in satellite images. RVO stated that at around 0800 on 20 October a large explosion at Southern Crater produced ash plumes that rose at least 1 km above the summit and drifted N and NW. According to the Darwin VAAC ash plumes rose as high as 15.2 km (50,000 ft) a.s.l. between 0840-0950, expanded radially, and then drifted E. Lower-level plumes rose 4.6-5.5 km (15,000-18,000 ft) a.s.l. and drifted NW. Later that day a collapse of newly erupted material, as well deposits from the previous few weeks, produced a debris flow that originated at the head of the valley and descended the SW Valley.

Pagan – Mariana Islands (USA) : The U.S. Geological Survey reported that ash and sulfur dioxide emissions from Pagan were last detected on 6 September. The Aviation Color Code and the Volcano Alert Level were both lowered to Unassigned on 24 September; Pagan is monitored with satellite imagery, distal geophysical data, and mariner reports and not ground-based instruments.

Rabaul – New Britain (Papua New Guinea) : On 6 October RVO raised the Alert Level for Rabaul to Stage 1 (the lowest level on a four-stage scale) due to ongoing deformation and recent increases in seismicity. During the month of September, the seismic network detected a total of 22 high-frequency volcano-tectonic earthquakes, which was more than the 12 recorded in August. The earthquakes were distributed in the Beehives, Vulcan, Greet Harbour, and Namanula areas. Deformation data from a GPS station located at the S part of Matupit Island showed a continuing trend of uplift, with 39 mm/month in August and 35-39 mm/month in September. Diffuse white fumarolic plumes rose from the crater floor and inner walls.

Vulcano – Aeolian Islands (Italy) : INGV continued to monitor elevated activity at Vulcano during 12-19 October. Scientists collected temperature, water chemistry, and gas-emissions data from four fumarolic vents located inside La Fossa Crater near the rim and from one vent near the beach. According to news articles, elevated levels of carbon dioxide impacted nearby residents in Porto Levante causing a few families to leave their homes on 13 October. Several residents had reported inexplicable illnesses and some deaths of domestic animals the previous week. On 14 October authorities restricted public access to the crater.

Volcanos

La Palma Destruction

The ongoing violent eruption of Spain’s La Palma volcano saw chunks of lava the size of buildings spewed from its craters.

Erratic and powerful lava flows forced an additional 800 residents from their homes as molten rock approached their municipalities. Nearly 7,000 people have evacuated since the Canary Island volcano began erupting on Sept. 19.

Lockdowns have been imposed when toxic gases from the eruption have threatened to blow over populated areas. Lava has destroyed more than 1,400 buildings on La Palma, including homes, farms and a cement factory.

Volcanos

Roundup of Global Volcanic Activity – Ongoing Activity for the Week 6 October – 12 October 2021

Aira – Kyushu (Japan) : JMA reported that incandescence from Minamidake Crater (at Aira Caldera’s Sakurajima volcano) was visible at night during 4-11 October. The sulfur dioxide emission rate was 400 tons per day on 5 October. An explosion at 0517 on 8 October ejected material 600-900 m away from the crater and produced an eruption plume that was obscured by weather clouds.

Kadovar – Papua New Guinea : Based on satellite and wind model data, the Darwin VAAC reported that during 8-9 October ash plumes from Kadovar rose to an altitude of 1.5 km (5,000 ft) a.s.l. and drifted W and NW.

Karymsky – Eastern Kamchatka (Russia) : KVERT reported that a thermal anomaly over Karymsky was identified in satellite images on 7 October.

Lewotolok – Lembata Island (Indonesia) : PVMBG reported that the eruption at Lewotolok continued during 6-12 October. White-and-gray plumes generally rose as high as 800 m above the summit and drifted in multiple directions. A VONA stated that on 7 October and ash plume rose 1.9 km above the summit and drifted W. Rumbling and banging sounds were reported daily. Incandescent material was ejected daily as far as 300 m away from the vent in multiple directions, though during 5-6 October incandescent material was ejected as far as 1 km SE. BNPB noted that 25-26 eruptive events per day were sometimes recorded before activity increased in October.

Merapi – Central Java (Indonesia) : BPPTKG reported minor morphological changes to Merapi’s SW lava dome, located just below the SW rim and in the summit crater, and no changes to the summit crater dome during 1-7 October. The SW dome grew about 3 m taller had an estimated volume of 1.679 million cubic meters, and the summit lava dome had an estimated volume of 2.854 million cubic meters. As many as 76 lava avalanches traveled a maximum of 2 km SW.

Nevados de Chillan – Chile : SERNAGEOMIN reported continuing explosive and effusive activity at Nevados de Chillán’s Nicanor Crater during 16-30 September though weather conditions often prevented visual confirmation. Explosions generated plumes with low ash content that rose as high as 1.1 km above the crater rim. A new lava dome (Dome 3) in the crater was first identified on 15 September and was 27 x 40 m, elongated NW-SE, and 990 square meters in area. The dome formation was preceded by a decrease in the extrusion rates and temperatures of the L5 and L6 lava flows. By 24 September growth at Dome 3 reached 36 x 43 m and covered 2,137 square meters. Dome 4 was first visible on 29 September, adjacent to Dome 3 on the NE side, and produced a new lava flow (L7) that traveled 50 m down the flank between the L5 and L6 flows. The L5 lava flow also began to advance. On 5 October the L5 and L7 lava flows advanced and nighttime incandescence from both flows increased. Incandescence from the crater was visible in webcam images at night during 8-9 October. On 9 October a long-period earthquake was recorded at 0706 on 9 October; an associated emission rose more than 240 m above the vent and drifted NW.

Pavlof – United States : AVO reported that seismicity at Pavlof remained elevated during 6-12 October. Two explosions were recorded by infrasound network during 6-7 October. Mostly cloudy conditions obscured satellite and webcam images most days.

Sabancaya – Peru : Instituto Geofísico del Perú (IGP) reported a daily average of 27 explosions at Sabancaya during 4-10 October. Gas-and-ash plumes rose as high as 2 km above the summit and drifted in multiple directions. One thermal anomaly originating from the lava dome in the summit crater was identified in satellite data. Minor inflation continued to be detected near Hualca Hualca (4 km N).

Semisopochnoi – Aleutian Islands (USA) : AVO reported that eruptive activity at Semisopochnoi’s North Cerberus crater continued during 6-12 October. Seismicity remained elevated and a few explosions per day were detected in infrasound data. Although weather clouds often prevented webcam and satellite views, discontinuous, low-level ash emissions were visible rising to altitudes up to 3 km (10,000 ft a.s.l.) and drifting E during 8-9 October. Low-level ash emissions were also visible in webcam images during 9-12 October.

Sheveluch – Central Kamchatka (Russia) : KVERT reported that a thermal anomaly over Sheveluch was identified in satellite images during 1, 4, and 6-7 October. Plumes of resuspended ash drifted 200 km SE during 6-7 October.

Stromboli – Aeolian Islands (Italy) : INGV reported that during 4-10 October activity at Stromboli was characterized by ongoing explosive activity from three vents in Area N (North Crater area) and six vents in Area C-S (South-Central Crater area). Explosions from two vents in the N1 vent (Area N) ejected lapilli and bombs 80 m high, and produced minor ash emissions. Explosions at two N2 vents (Area N) averaged 3-8 events per hour and ejected material less than 80 m high. Explosions from the S1 and S2 vents in Area C-S were sporadic and occurred at a rate of 4-8 per hour; coarse material was ejected 150 m high. Gas emissions rose from the C vent. A short explosive event at the N2 vents began at 1617 on 6 October. Notably, a large explosion ejected tephra radially beyond the crater terrace as far as the upper part of the Sciara del Fuoco, and incandescent material rolled down to the coast. An ash cloud was produced, though it quickly dissipated. A small lava overflow from the vents followed but it did not travel past the upper part of the Sciara del Fuoco

Suwanosejima – Ryukyu Islands (Japan) : JMA reported that 52 explosions at Suwanosejima’s Ontake Crater produced eruption plumes that rose as high as 2.4 km above the crater rim during 4-11 October. Large volcanic bombs were ejected as far as 1.1 km from the crater. Crater incandescence was visible nightly.

Volcanos

Roundup of Global Volcanic Activity – New Activity for the Week 6 October – 12 October 2021

Kilauea – Hawaiian Islands (USA) : HVO reported that the summit eruption at Kilauea continued in Halema`uma`u Crater during 6-12 October. At the beginning of the eruption, on 29 September, lava erupted from vents along the floor and from the W wall of the crater, though by 8 October only the W vent was active. Sulfur dioxide emissions remained high and were 5,300 tonnes per day on 8 October. A 10-m-wide, horseshoe-shaped spatter rampart had formed around the W vent and was open to the E where lava was feeding the lake. Lava fountains from the W vent were generally 12-15 m high but decreased to 4 m during 10-11 October. The total erupted volume was an estimated 15.9 million cubic meters on 8 October and the lake was as deep as 40 m on 12 October. The lava lake was not level; the W end was 2-3 m higher than the N and S parts of the lake and 5 m higher than the E end. Cooled and crusted parts of the lake’s surface overturned, or “foundered,” in all parts of the lake, though by 11 October foundering was not observed in the E. HVO noted that the central island (or raft) of cooler material from the 2020 eruption remained above the surface as the lava lake rose, and other smaller rafts had reemerged in the E and N parts of the lake.

La Palma – Spain : The eruption at La Palma continued during 6-12 October, characterized by Strombolian explosions, lava fountaining from multiple vents, advancing and branching lava flows, and daily ash emissions. Eruption details are based on official sources including PEVOLCA (Plan de Emergencias Volcánicas de Canarias) steering committee summaries. Seismicity continued to be elevated with most earthquakes located 10-15 km deep (though some deeper than 35 km) in the same area where the swarm first began on 11 September; dozens of events were felt by local residents and some were felt across the entire island.

The largest earthquake, at 0816 on 12 October, was a M 4.1 at a depth of 37 km. Sulfur dioxide emissions fluctuated at high levels between 4,522 and 21,868 tons per day. Sulfur dioxide plumes drifted in multiple directions; on 8 October they reached the Caribbean and on 12 October plumes were over northern Africa, Spain, and Portugal. The main cone had at least three effusive vents and another vent to the N was also active. Multiple collapses of parts of the cone sometimes sent large blocks of cooler lava rafting down the flows. The lava delta was fed by numerous streams of lava during most of the week. Plumes of steam containing hydrochloric acid rose from the edge of the lava delta and were quickly dissipated by the wind; local resident were not affected.

On 6 October a breakout lava flow from the W end of the main flow field traveled S between Los Guirres and El Charcó (previously evacuated), destroying crops and buildings. The flow covered about 0.4 square kilometers and was about 350 m from the coast. Ash plumes rose 3-3.2 km (10,000-10,500 ft) a.s.l. during 6-7 October. On 8 October a new vent formed on the main cone and ash plumes rose as high as 3.5 km (11,500 ft) a.s.l. Ash accumulation at the La Palma and Tenerife North (on Tenerife Island) airports caused a temporary shutdown of operations until the ash was removed. On 9 October a collapse of the N part of the cone sent a wide, multi-lobed flow carrying larger blocks NW over older flows that quickly advanced W along the N margins of the flow field, covering crops and destroying buildings in both Todoque and an industrial area. Ash plumes continued to rise from the vents; lightning was visible in the plume at times.

By 10 October the flow field was 1,520 m wide, and covered 4.9-5.7 square kilometers, depending on the source of the estimates. Between 726 and 1,323 buildings had been engulfed by lava and more than 1.3 square kilometers of crops were lost. About 6,000 people had been evacuated. A partial collapse of the cone allowed the inner lava lake to spill out, sending flows and very large cooled blocks downslope. Ash plumes rose 3.5 km a.s.l. and caused ashfall to the S. Video showed lava fountains rising 500 m above the vent late that night. By 11 October the lava delta had grown mainly to the N and S, and was an estimated 0.34 square kilometers in size, though flows feeding it had slowed. Dense dark ash plumes were seen rising from the main vents. The most northern flow had continued to advance and was 300 m from the coast. The flows overtook a concrete plant, prompting authorities to instruct residents in El Paso and Los Llanos de Aridane to remain indoors and take measures to reduce exposure to toxic fumes. On 12 October the advancing northern flow caused the pre-emptive evacuation of the La Laguna area, totaling 700-800 people. The flow continued to cover crops and was 200 m from the coast, but had slowed. The lockdown for El Paso and Los Llanos de Aridane was lifted after air quality improved. Ash plumes from the main vent rose 3.5 km a.s.l. The Alert Level remained at Red (the highest level on a four-color scale) for affected communities.

Volcanos

Roundup of Global Volcanic Activity – Ongoing Activity for the Week 29 September – 5 October 2021

Aira – Kyushu (Japan) : JMA reported that incandescence from Minamidake Crater (at Aira Caldera’s Sakurajima volcano) was visible at night during 27 September-4 October. The trend of inflation that was first detected on 13 September continued. The sulfur dioxide emission rate was 1,500 tons per day on 28 September. A very small eruptive event occurred on 3 October.

Great Sitkin – Andreanof Islands (USA) : AVO reported that lava effusion continued at Great Sitkin during 29 September-5 October. Seismicity remained elevated and was characterized by small earthquakes consistent with lava effusion. Elevated surface temperatures were detected in satellite images. By 3 October the dome had grown to 1,200 m E-W and 1,000 m N-S. Lava flows that continued to advance down the S and SW flanks were about 300-350 m long. The SW lobe was descending two drainages and produced hot avalanches that traveled 450 m downslope on top of a snow field.

Karymsky – Eastern Kamchatka (Russia) : KVERT reported that a thermal anomaly over Karymsky was identified in satellite images during 24-28 September. Ash plumes rose as high as 4.6 km (15,100 ft) a.s.l. and drifted 100 km E, SE, and SW during 24-26 September.

Katmai – United States : AVO reported that beginning at 0400 on 2 October strong winds in the vicinity of Katmai and the Valley of Ten Thousand Smokes blew unconsolidated ash SE towards Kodiak Island at an altitude up to 1.8 km (6,000 ft) a.s.l. The ash was originally deposited during the Novarupta eruption in 1912.

Klyuchevskoy – Central Kamchatka (Russia) : On 29 September strong winds resuspended unconsolidated ash from Klyuchevskoy’s flanks.

Krysuvik-Trolladyngja – Iceland : The Institute of Earth Sciences reported that lava effusion at Krýsuvík-Trölladyngja volcanic system, close to Fagradalsfjall on the Reykjanes Peninsula, likely ceased during the evening of 18 September. The area of the flow field was about 4.85 square kilometers, and the total volume erupted was 150 million cubic meters, based on 30 September measurements. Parts of lava flows thickened in areas to the S of Geldingadalur and in Nàtthagi valley, and deflated in areas N of Geldingadalur. Points of incandescence were visible at night, at least through 4 October, likely from lava flows that continued to advance downslope. A seismic swarm in an area SW of Keilir (about 10 km NE of the fifth vent), at the N end of the dike intrusion, began on 27 September. According to news reports, over 6,000 earthquakes at depths of 5-6 km had been recorded by 4 October with at least 12 of them over M 3; the largest event was a M 3.8. Some of the larger events were felt in the capital. The seismicity was similar to patterns recorded before the beginning of the eruption to the SW. IMO stated that more data was needed to characterize the data as either indicative of magma movement or due to tectonic stress. IMO warned of the potential for lapilli and scoria fallout within a 650 m radius of the active vent. Authorities also warned of gas emission hazards.

Langila – New Britain (Papua New Guinea) : The Darwin VAAC reported that a discrete ash plume from Langila rose to 1.8 km (6,000 ft) a.s.l. on 3 October and drifted S. A thermal anomaly was visible afterward. On 4 October an ash plume again rose to 1.8 km a.s.l. and drifted S.

Lewotolok – Lembata Island (Indonesia) : PVMBG reported that the eruption at Lewotolok continued during 28 September-4 October. White-and-gray plumes rose as high as 800 m above the summit and drifted NW, W, and SW. Rumbling sounds were reported almost daily. During 30 September-1 October and 3-4 October incandescent material was ejected as far as 700 m away from the vent in multiple directions.

Merapi – Central Java (Indonesia) : BPPTKG reported minor morphological changes to Merapi’s SW lava dome, located just below the SW rim and in the summit crater, and no changes to the summit crater dome during 24-30 September. The SW dome grew 1 m taller and had an estimated volume of 1.63 million cubic meters; the summit lava dome had an estimated volume of 2.85 million cubic meters. As many as 67 lava avalanches traveled a maximum of 1.8 km SW.

Pavlof – United States : AVO reported that seismicity at Pavlof remained elevated during 29 September-5 October. No explosions were recorded most days by the seismic and infrasound networks, and no eruptive activity was observed in mostly cloudy webcam and satellite images. On 3 October webcam images showed that recent ash deposits on the flanks had been covered by fresh snow; later that night either new ash deposits were visible in webcam images or older deposits were revealed due to snowmelt. Weakly elevated surface temperatures were identified in satellite images. At least two minor explosions were recorded during 4-5 October and minor emissions likely comprised of steam and sulfur dioxide were visible in morning webcam images on 5 October.

Reventador – Ecuador : IG reported that a high level of activity continued to be recorded at Reventador during 29 September-3 October; cloudy weather conditions sometimes prevented webcam and satellite views. Gas-and-ash plumes, often observed multiple times a day with the webcam or reported by the Washington VAAC, rose as high as 1 km above the summit crater and drifted mainly W and NW. Crater incandescence was often observed at night along with incandescent blocks that rolled as far as 800 m down the flanks.

Sangay – Ecuador : IG reported a high level of activity at Sangay during 28 September-5 October. Weather clouds and rain sometimes prevented visual and webcam observations of the volcano. Ash plumes were identified in satellite images by the Washington VAAC or in webcam views during 30 September-1 October and 3 and 5 October; plumes rose 500-1,200 m above the volcano and drifted W and SW. Thermal anomalies over the volcano were often visible in satellite data. .

Semisopochnoi – Aleutian Islands (USA) : AVO reported that eruptive activity at Semisopochnoi’s North Cerberus crater continued during 29 September-5 October. Seismicity remained elevated with intermittent explosion signals or bursts of activity likely from explosions. A few explosions were also detected in regional infrasound data during 2-5 October. Small ash clouds were observed almost daily in either webcam or satellite images rising to altitudes below 3 km (10,000 ft) a.s.l.; plumes drifted ENE on 2 October, then N and NW on 3 October. Sulfur dioxide plumes were possibly observed on a few days, though definitely on 3 October. Webcams located 5-6 km from the active vent recorded ashfall during 4-5 October.

Sheveluch – Central Kamchatka (Russia) ; KVERT reported that a thermal anomaly over Sheveluch was identified in satellite images during 24 September-1 October.

Suwanosejima – Ryukyu Islands (Japan) : JMA reported that 129 explosions at Suwanosejima’s Ontake Crater produced eruption plumes that rose as high as 3 km above the crater rim during 27 September-4 October. Large volcanic bombs were ejected as far as1 km from the crater. Crater incandescence was visible nightly.

Taal – Luzon (Philippines) : PHIVOLCS reported that sulfur dioxide emissions at Taal averaged 8,854 tonnes/day beginning on 27 September, and peaked on 5 October at 25,456 tonnes/day which was the highest ever sulfur dioxide gas flux recorded at the volcano. On 27 September the number of daily volcanic earthquakes significantly decreased. During 27 September-5 October upwelling of hot volcanic fluids in the lake was visible and gas-and-steam plumes rose as high as 3 km above the lake. The report noted that a sudden increase in inflation below Taal Volcano Island was recorded in August. The Volcano Alert Level remained at a 2 (on a scale of 0-5). PHIVOLCS reminded the public that the entire Taal Volcano Island is a Permanent Danger Zone (PDZ) and that boating on Taal Lake was prohibited.

Telica – Nicaragua : INETER reported that on 4 September a diffuse ash plume from Telica rose 1.2 km (4,000 ft) a.s.l. and drifted less than 10 km WSW, based on satellite images and model data.

Yasur – Vanuatu : On 30 September the Vanuatu Meteorology and Geo-Hazards Department (VMGD) reported that seismic data and recent visual observations at Yasur confirmed ongoing explosions and gas-and-ash emissions. A few earthquakes were recorded on 28 September. The Alert Level remained at 2 (on a scale of 0-4). VMGD reminded residents and tourists that hazardous areas were near and around the volcanic crater, within a 600-m-radius exclusion zone, and that volcanic ash and gas could reach areas impacted by trade winds.

Volcanos

Roundup of Global Volcanic Activity – New Activity for the Week 29 September – 5 October 2021

Kilauea – Hawaiian Islands (USA) : Seismicity abruptly increased below Kilauea’s summit at about 1400 on 29 September. Around 30 minutes later the earthquakes became more intense, frequent, and shallower, and deformation patterns rapidly changed. The data suggested an upward movement of magma that prompted HVO to raise the Aviation Color Code to Orange and the Volcano Alert Level to Watch at 1509. A new eruption was identified at 1521 when incandescence from Halema`uma`u Crater became visible in webcam views; HVO raised the Aviation Color Code to Red and the Volcano Alert Level to Warning. Fissures opened along the bottom of Halema`uma`u Crater floor and produced lava fountains and flows. A photo taken at 1615 showed a large plume comprised of steam, carbon dioxide, and sulfur dioxide rising from the fissures. Measurements just after the eruption started showed sulfur dioxide emissions of around 85,000 tonnes/day. At about 1640 another fissure with several vents opened on the inner W wall of the crater and produced low lava fountains and flows that descended to the crater floor. The vent expanded by 1709. Lava from both fissures pooled on the solidified lava lake surface and quickly began to overturn and create a lava lake. Tephra was deposited in areas SW of the crater and collected by HVO scientists for analysis. The tallest lava fountain was near the S end of the lava lake and rose 20-25 m during the night of 29-30 September. During a helicopter overflight around 0730 on 30 September scientists determined that the lake was about 980 m E-W and 710 m N-S, covering an estimated 52 hectares. The W wall vent was visible, and several fountains were rising from the fissure in the central part of the lake. Sulfur dioxide emission rates remained high, estimated at around 20,000 tonnes/day. Overnight during 30 September-1 October fountains rose as high as 15 m at the dominant vent in the W wall. Less vigorous fountaining persisted at other vents, though fewer were active. The lake had risen 24 m by the morning of 1 October, adding 4 m in the past day. Cooled and crusted parts of the lake’s surface overturned, or “foundered.” Sulfur dioxide emission rates remained high, estimated at around 12,900 tonnes per day. The lake had risen another 2 m by the morning of 2 October; fountains were 7 m tall at the main W wall vent and 1-2 m at the southern vents. Fountains occasionally rose as high as 50-60 m in bursts. Pumice, Pele?s hair, and fragments of volcanic glass were deposited downwind. The sulfur dioxide emission rate on 3 October was again high at 14,750 tonnes/day. The W vent was again the most vigorous during 3-4 October with sustained lava fountains to 10-15 m with occasional bursts up to 20 m. The lake rose 3 m, past the base of the W vent where a 12-m-high spatter cone had formed, and continued to founder in spots. Lava fountains rose 5-10 m from the vents in the S and central portions of the lake, including along a fissure 35-42 m long, with occasional larger bursts. The lake was not level and generally higher near the location of the vents; the W end was 1-2 m higher than the E, and S end was about 1 m higher than the N. By 4 October ledges about 20 m wide separated the N and E parts of the active lava lake from the crater wall and were lower than the lake surface; the N, E, and S margins of the lake were perched about 3 m above the surrounding ledge. The sulfur dioxide emission rate remained elevated but had decreased to 7,000-9,000 tonnes/day. HVO lowered the Aviation Color Code to Orange and the Volcano Alert Level to Watch at 1652. On 5 October lava fountaining from the W vent was unchanged while fountains from the other vents rose 1-5 m. The lake rose 1 more meter.

La Palma – Spain : The eruption at La Palma continued during 29 September-5 October, characterized by Strombolian explosions, lava fountaining from multiple vents, lava flows, and daily ash emissions. Seismicity continued to be elevated with earthquakes located mainly 10-15 km deep (though some were 25-40 km deep) in the same area where the swarm first began on 11 September; dozens of events were felt by residents. Within the first eight days of the eruption, 21-27 September, an estimated 50 million cubic meters of material had been erupted. Just before midnight on 28 September the lava reached the ocean, producing a steam-and-gas plume; within 45 minutes the lava created a 50-m-high delta. The sulfur dioxide flux was as high as 16,760 tons per day. On 29 September the PEVOLCA (Plan de Emergencias Volcánicas de Canarias) steering committee restated that the 2.5 km and maritime exclusion zones around the vents and ocean entry, respectively, remained in effect; residents were periodically allowed to collect belongings and care for animals and crops. The lava covered almost 4.8 square kilometers, burying or damaging 744 buildings. There were 185 evacuees in a local hotel. Ash plumes continued to rise from the active vents, and IGN noted a decrease in plume altitude to 3.5 km (11,500 ft) a.s.l. on 29 September and then a rise to 5 km (16,400 ft) a.s.l. the next day. Lava continued flowing to the sea along the same path. The lava delta had grown three times in size by 30 September to an estimated 0.17 square kilometers; the furthest edge of the delta was 450 m from the coast, it had spread laterally 600-800 m, and was as thick as 24 m. PEVOLCA lifted access restrictions for residents of Tazacorte, San Borondón, Marina Alta, Marina Baja, and La Condesa (nearly 4,000 people); they had previously been warned to stay indoors to minimize coming into contact with potentially toxic gas plumes generated from the ocean entry. Restrictions for other residents living near the margins of the flows were also lifted. Two vents opened about 600 m NW of the main cone on 1 October and within two days had formed small cones. Lava from the vents traveled W and joined the main flow field downslope. The lava delta had extended 540 m from the coastline. Ash plumes rose to 3-5 km a.s.l. and drifted S on 2 October, and sulfur dioxide emissions were 3,401 tons per day. By 3 October an estimated 946 houses had been completely demolished and 128 had been partially damaged. The width of the flow field was a maximum of 1,250 m and lava tubes were identified in satellite images. The lava delta had developed four lobes being fed by multiple flows and had an estimated area of 0.32 square kilometers. In the afternoon the frequency and intensity of explosive activity increased and bombs were ejected as far as 800 m. Lava fountains rose hundreds of meters and ash plumes rose as high as 4.5 km (14,800 ft) a.s.l. The sulfur dioxide emission rate reached 16,000 tons per day. During 1900-1945 one of the new cones collapsed, which allowed the inner lava lake to spill out, sending flows downslope carrying blocks from the destroyed portion of the cone. Ash plumes rose as high as 4.5 km a.s.l. and explosions ejected bombs on 5 October according to a news report. Some explosions produced dense black plumes that billowed as they rose above the vent.

Nyiragongo – DR Congo : According to a news article the scientific director of GVO stated that lava had returned to Nyiragongo’s crater on 18 September. Notable thermal anomalies were visible in Sentinel satellite images on 29 September and 4 October.

Vulcano – Aeolian Islands (Italy) : INGV reported that hydrothermal activity at Vulcano increased in July, and notably more in September. Specifically, temperatures of the fumaroles on the crater rim and on the inner flank had increased along with the amounts of carbon dioxide and sulfur dioxide in the emissions. The highest temperature of 340 degrees Celsius was along the rim. The temperature and salinity of groundwater measured near the base of La Fossa cone were both elevated, and outgassing from ground sites was noted. On 13 September the seismic network detected a significant increase in microseismcity linked to hydrothermal processes. Additionally, very-long-period events were also recorded for the first time in 15 years when instrumentation able to detect the signals was installed. Deformation on the N side of the cone was first identified in mid-August and totaled 1 cm of uplift by mid-September. The report stated that new seismic stations and instruments to measure carbon dioxide emissions had been added to the monitoring network, and a thermal camera pointing at the fumarolic field was planned.

Volcanos

Roundup of Global Volcanic Activity – Ongoing Activity for the Week 22 September – 28 September 2021

Aira – Kyushu (Japan) : JMA reported that incandescence from Minamidake Crater (at Aira Caldera’s Sakurajima volcano) was visible on most nights during 20-27 September. The trend of inflation first detected on 13 September had begun to slow down by 21 September. The sulfur dioxide emission rate was high at 2,600 tons per day on 22 September. An eruptive event at 0110 on 23 September and two more during 24-27 September produced plumes that rose 1.1 km above the crater rim.

Ebeko – Paramushir Island (Russia) : According to volcanologists in Severo-Kurilsk (Paramushir Island), about 7 km E of Ebeko, explosions on 20 September produced ash plumes that rose as high as 1.7 km (5,600 ft) a.s.l. and drifted SE.

Fuego – Guatemala : INSIVUMEH reported that during the night of 21-22 September a possible lava flow had traveled 400 m down Fuego’s Ceniza drainage on the SSW flank. Ash rose along the flow forming a curtain that extended above the summit; ash fell in communities to the W and SW. Explosions at a rate of 6-11 per hour produced ash plumes that rose as high as 800 m above the summit and drifted W and SW. INSIVUMEH and CONRED reported that activity significantly increased on 23 September. Seismic activity intensified during the early morning and Strombolian activity at the summit was visible. Incandescent material was ejected 100-300 m high. Lava flows traveled 1 km down the Ceniza (SSW) and Trinidad (S) drainages, and sent block-and-ash flows down the Ceniza, Trinidad, Taniluyá, Las Lajas, and Santa Teresa (W) drainages to vegetated areas. Shock waves were detected within a 10 km radius. At 0540 a pyroclastic flow traveled 4-6 km down the Ceniza drainage, reaching the base of the volcano. According to CONRED a pyroclastic flow descended the Ceniza and Trinidad drainages 2-4 km. Explosions generated ash plumes that rose as high as 2.3 km above the summit and drifted 30 km W and SW. The activity began to decline around noon the next day, based on seismicity, acoustic data, and field observations. A few hours later RSAM data suggested that the period of elevated activity had ended after about 32 hours from the onset. Lava flows were no longer active by 25 September. During 24-28 September there were that 6-12 explosions per hour generating ash plumes as high as 1.1 km above the crater rim and shock waves that often rattled buildings within 10 km of the volcano. Ash plumes mostly drifted as far as 15 km W and SW, causing daily ashfall in several areas downwind, including Morelia (9 km SW), Panimaché I and II (8 km SW), Santa Sofía (12 km SW), Finca Palo Verde, and San Pedro Yepocapa (8 km NW). Block avalanches descended the Ceniza (SSW), Seca (W), Trinidad (S), Taniluyá (SW), Las Lajas (SE), and Honda drainages, often reaching vegetated areas. Explosions ejected incandescent material 100-300 m above the summit on most days.

Great Sitkin – Andreanof Islands (USA) : AVO reported that lava effusion continued at Great Sitkin during 22-28 September, though weather clouds sometimes prevented webcam and satellite views. Seismicity remained elevated and was characterized by small earthquakes consistent with lava effusion. By 24 September the dome had overtopped the S and W crater rims and flowed 305 m down the S flank and 195 m down the W flank. The dome was about 25 m thick and had grown to 1,170 m E to W and 925 m N to S in dimension.

Karymsky – Eastern Kamchatka (Russia) : KVERT reported that a thermal anomaly over Karymsky was identified in satellite images during 16-18 and 22 September. Ash plumes rose as high as 4.5 km (14,800 ft) a.s.l. and drifted 180 km E during 16, 18-19, and 22 September.

Katmai – United States : AVO reported that beginning at 1730 on 23 September strong winds in the vicinity of Katmai and the Valley of Ten Thousand Smokes blew unconsolidated ash SE towards 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.

Klyuchevskoy – Central Kamchatka (Russia) : KVERT reported that on 29 September high winds caused unconsolidated ash from Klyuchevskoy’s flanks to form plumes that rose to 3-5 km (9,800-16,400 ft) a.s.l. and drifted 75 km E.

Langila – New Britain (Papua New Guinea) : Based on analyses of satellite imagery and wind model data, the Darwin VAAC reported that during 24-25 September three ash plumes from Langila rose to 2.1 km (7,000 ft) a.s.l. and drifted W and NW.

Lewotolok – Lembata Island (Indonesia) : PVMBG reported that the eruption at Lewotolok continued during 21-28 September. White-and-gray plumes rose as high as 700 m above the summit and drifted NW, W, and SW. Rumbling sounds were reported almost daily.

Merapi – Central Java (Indonesia) : BPPTKG reported minor morphological changes to Merapi’s SW lava dome, located just below the SW rim and in the summit crater, and no changes to the summit crater dome during 17-23 September. The SW dome had an estimated volume of 1.6 million cubic meters and the summit lava dome had an estimated volume of 2.85 million cubic meters. As many as 141 lava avalanches traveled a maximum of 2 km SW.

Pavlof – United States : AVO reported that seismicity at Pavlof remained elevated during 21-28 September. Daily short-lived explosions from a vent on the upper SE flank were detected in seismic and infrasound data. Low-level ash emissions were visible in webcam images rising possibly several hundred meters above the summit during 21-23 September. Steam emissions rose from the vent during 24-25 September.

Ruapehu – North Island (New Zealand) : GeoNet reported that a heating cycle at Ruapehu’s summit Crater Lake had ended. During the previous two months the temperature of the water increased from 20 degrees Celsius to a peak of 39.5 degrees on 4 September, and then decreased to 28 degrees. During the cycle the color of the lake changed from a blue-green color to a darker gray, reflecting the disturbed lake floor sediments suspended in the water from the influx of hot fluids. The key monitoring parameters of water level and temperature, seismic activity, and tremor levels, were all within normal ranges.

Santa Maria – Guatemala : INSIVUMEH reported that almost daily ash plumes from Santa Maria’s Santiaguito lava-dome complex rose 500-900 m and drifted W and SW during 19-27 September, depositing ash on the flanks. Extrusion continued at the summit dome complex, mainly from the W part of the dome. Avalanches produced by the active dome were sometimes incandescent and predominantly descended the W flank, though some also traveled S and SW. The avalanches often reached vegetated areas on the flanks.

Semisopochnoi – Aleutian Islands (USA) : AVO reported that eruptive activity at Semisopochnoi’s North Cerberus crater continued during 22-28 September. Seismicity remained elevated; daily explosions were recorded by seismic and infrasound networks. The frequency and intensity of ash emissions decreased during 21-22 September with occasional discrete ash clouds drifted W at altitudes of 3-4.6 km (10,000-15,000 ft) a.s.l. Sulfur dioxide plumes also drifted W. Occasional low-level ash emissions drifted NW, W, and SE during 22-26 September.

Sheveluch – Central Kamchatka (Russia) : KVERT reported that a thermal anomaly over Sheveluch was identified in satellite images during 17-24 September.

Suwanosejima – Ryukyu Islands (Japan) : JMA reported that the number of explosions per day at Suwanosejima’s Ontake Crater had increased on 16 September and remained elevated through 27 September. A total of 105 explosions were recorded during 20-27 September. Eruption plumes mainly rose as high as 2.9 km above the crater rim and material was ejected as far as 800 m away from the crater. Ashfall was reported in Toshima village (4 km SSW). Notably, an explosion at 2349 on 20 September ejected material as far as 1.2 km SE. At 0711 on 26 September an eruptive event produced a plume that rose 5.4 km; weather clouds prevented confirmation of ejected bombs, but a large amount of ash fell in Toshima village.

Tengger Caldera – Eastern Java (Indonesia) : PVMBG reported that during 21-27 September white gas-and-steam plumes rose as high as 400 m above the rim of Tengger Caldera’s Bromo cone and drifted SW, W, and NW. White-and-gray plumes rose as high as 500 m during 22-23 September. A weak thermal anomaly was visible in Sentinel-2 infrared satellite images on 22 and 27 September.

Whakaari/White Island – North Island (New Zealand) : On 27 September GeoNet reported results from an overflight of Whakaari/White Island the previous week. Gas measurements showed that sulfur dioxide emissions had increased to 680 tons per day from 450 tons per day recorded in mid-August, continuing the trend of an increasing emission rate noted over the past few months. The gas data suggested magma input deeper in the system. Temperatures in the main vent area notably decreased to 189 degrees Celsius from July and August measurements of 650 degrees, possibly indicating cooling caused by groundwater infiltration. Minor ash deposits from recent emissions were visible around the active vents. Seismicity was characterized by low levels of volcanic tremor and occasional low-frequency volcanic earthquakes. Subsidence continued to be measured by satellite.

Volcanos

Roundup of Global Volcanic Activity – New Activity for the Week 22 September – 28 September 2021

La Palma – Spain : The eruption at La Palma continued during 21-28 September, characterized by Strombolian explosions, lava fountaining from multiple vents, advancing lava flows, and sometimes dense, daily ash emissions. A strong increase in tremor amplitude during the afternoon of 21 September was coincident with intensifying Strombolian activity. Explosive activity again increased on 22 September and dense plumes with abundant amounts of ash rose 3-4.6 km (10,000-15,000 ft) a.s.l. and caused ashfall in areas downwind; ash deposits were 3 cm thick in an unspecified area 1 km from the vents. The main lava flow advanced W towards the coast. Ash emissions significantly increased on 23 September with plumes rising as high as 5 km (16,400 ft) a.s.l. A series of powerful explosions began at 1720 and shock waves could be seen propagating through the emission plumes. Vigorous lava fountaining was continuous. Volcanic tremor amplitude was high and variable, peaking at 1500 on 24 September with the highest values since the eruption started. The peak occurred just before two new vents opened on the flank of the main cone, and then notably decreased afterwards, but remained at high levels. Lava from the new vents rapidly traveled more than 1 km downslope, covering older flows, before slowing to 60-80 meters per hour. According to a news report, the explosions ejected tephra outside of the exclusion zone. An evacuation order was issued in the early afternoon for Tajuya, Tacande de Abajo, and part of Tacande de Arriba, affecting 300-400 people. Three airlines suspended flights to La Palma. The lava flow field had expanded to 1.9 square kilometers, destroyed more than 420 buildings, and covered 15.2 km of roads.

Tremor amplitude decreased around noon on 25 September, along with the intensity of the Strombolian explosions. During 25-26 September ash fell in nearby municipalities and as far as the E coast of the island. On 26 September the PEVOLCA steering committee recommended that residents who had evacuated two days earlier could return. The report described two main lava flows, with a highly fluid northern flow and a southern flow that was 2.5 km long. Sulfur dioxide emissions remained significant with an average rate of 25,000 tons per day, and ash plumes rose as high as 3 km above the vents. Lava continued to advance and flowed through Todoque, crossing the LP-213 road, just W of the main part of the town, at around 1900. The flow was 600 m across at the widest part and the leading edge was 4-6 m tall. Lava fountaining and low-intensity Strombolian explosions persisted. Copernicus EMS estimated that the lava covered 2.37 square kilometers, had destroyed 513 houses, and covered 18.9 km of roads. Multiple lava fountains feeding flows were visible on 27 September though the activity waned for a period of about eight hours. By the evening activity had resumed and low-intensity Strombolian explosions were visible.

Beginning at 0245 on 28 September lava fountains fed a new high-temperature, fast-moving flow that descended on top of older flank flows. The leading edge of the main flow continued to advance W and covered banana greenhouses, burning the plastic and igniting a storage of fertilizer resulting in small explosions and a brown odorous plume. About 140 more structures were covered by flows. In preparation for a possible ocean entry, authorities recommended that residents within a 5 km radius of the coastline keep their doors and windows closed, to stay away from windows in case they break, and to cover faces and skin in case of ashfall. Dense ash-and-gas plumes continued to rise from the main vents, as high as 5 km; the rising plume created gravity waves that looked like ripples moving away from the top of the plume. Late in the day lava reached the coastal area, descended a 100-m-high sea cliff, and by 2302 reached the ocean at Playa de los Guirres. Black-and-white plumes rose from where the lava contacted the water.

Nyiragongo – DR Congo : OVG reported that lava had returned to Nyiragongo’s summit crater based on a 29 September Sentinel satellite image.

Volcanos

Roundup of Global Volcanic Activity – Ongoing Activity for the Week 15 September – 21 September 2021

Agung – Bali (Indonesia) : PVMBG reported that activity at Agung was last observed on 13 June 2019 and a thermal anomaly over the crater was last identified in satellite images in October 2019. During the previous year deformation data indicated no changes at the volcano and seismicity decreased. During 1 Janaury-13 September white gas-and-steam plumes rose 20-50 m above the summit.

Aira – Kyushu (Japan) : JMA reported that an explosion at Minamidake Crater (at Aira Caldera’s Sakurajima volcano) at 1617 on 19 September produced an eruption plume that rose 1 km above the crater rim. Crater incandescence was visible at night during 20-21 September. The report noted that inflation around the summit continued to be recorded.

Chirinkotan – Kuril Islands (Russia) : SVERT and KVERT reported that volcanic activity at Chirinkotan was last observed during 23-24 August. The Aviation Color Code was lowered to Green in mid to late September.

Ebeko – Paramushir Island (Russia) : According to volcanologists in Severo-Kurilsk (Paramushir Island), about 7 km E of Ebeko, explosions during 10-11 September produced ash plumes that rose as high as 2 km (6,600 ft) a.s.l. and drifted S and SE.

Etna – Sicily (Italy) : INGV reported that tremor amplitude at Etna began gradually increasing at 0420 on 21 September and then suddenly increased at 0440. Ash emissions rose from the Southeast Crater (SEC) at 0815 and by 0855 Strombolian activity was visible. An eruption plume rose 4.5 km above the summit and drifted ENE. Within an hour lava fountaining began and the plume rose 9 km and drifted ENE. Lava overflowed the crater and traveled SW. Lava fountaining had ceased by 1130, though Strombolian activity within the crater continued. Tremor amplitude decreased at 1250 and explosive activity ceased.

Great Sitkin – Andreanof Islands (USA) : AVO reported that lava effusion continued at Great Sitkin during 15-21 September, though weather clouds often prevented webcam and satellite views. Seismicity remained elevated and was characterized by small earthquakes consistent with lava effusion. A radar image from 16 September indicated that the lava dome had grown to 1,130 m E-W and 910 m N-S, and was about 30 m thick. The edges of the dome touched the S and W rims of the crater. Elevated surface temperatures were identified in satellite data during 20-21 September.

Karymsky – Eastern Kamchatka (Russia) : KVERT reported that a thermal anomaly over Karymsky was identified in satellite images during 10-17 September. Ash plumes rose as high as 7 km (23,000 ft) a.s.l. and drifted 180 km E and SE during 10 and 15-16 September.

Katmai – United States : AVO reported that on 21 September strong winds in the vicinity of Katmai and the Valley of Ten Thousand Smokes blew unconsolidated ash SE towards Kodiak Island at an altitude up to 2.4 km (8,000 ft) a.s.l. The ash was originally deposited during the Novarupta eruption in 1912.

Krysuvik-Trolladyngja – Iceland : The eruption from the fifth vent in the W part of the Krýsuvík-Trölladyngja volcanic system, close to Fagradalsfjall on the Reykjanes Peninsula, continued during 15-18 September. According to a news article lava ponded for a few days in Geldingadalur, and during 14-15 September the crust ruptured and sent a larger lava flow rapidly into the S part of the valley; the flow then turned E into the Nàtthagi valley. Authorities temporarily closed the area due to the activity and the large number of tourists; the Coast Guard rescued two people whose exit route had been cut off by the flow. Lava continued to flow on this path during 16-17 September and overtook the “A” hiking trail. Later that day at around 1800 the flow rate decreased or paused, and only minor incandescence from the vent was visible. The Institute of Earth Sciences reported that based on aerial photography acquired on 17 September the area of the flow field had grown to 4.8 square kilometers, and the total volume erupted was 151 million cubic meters. The lava-flow rate during 11-17 September averaged 16 cubic meters per second. IMO noted that 19 September marked six months since the eruption started.

Merapi – Central Java (Indonesia) : BPPTKG reported that no morphological changes to Merapi’s two lava domes, situated just below the SW rim and in the summit crater, were detected during 10-16 September. As many as 144 lava avalanches traveled a maximum of 2 km SW.

Pavlof – United States : AVO reported that periods of elevated seismic tremor with no clear explosion signals were recorded at Pavlof during 14-18 September. Webcam images were mostly obscured by weather clouds. Minor ash deposits on the upper flanks and at least one minor ash emission was visible in a clear webcam view on 18 September. Small low-level ash emissions that dissipated quickly were noted by observers and visible in webcam images at 1500 on 19 September and at 0900 on 20 September. Ash deposits on the mid-flanks were identified in satellite data. Seismicity remained elevated during 2021 September; an explosion was recorded early on the 21 September. The vent in the crater continued to migrate N based on satellite data.

Popocatepetl – Mexico : CENAPRED reported that each day during 14-21 September there were 89-152 steam-and-gas emissions from Popocatépetl. The plumes drifted mainly NW and some contained ash. As many as five daily explosions were recorded during 14-19 September and some ejected incandescent material onto the flanks. Explosions at 1818, 1839, and 2350 on 14 September produced ash plumes that rose 1.2-1.5 km above the crater rim. Explosions at 1015 and 1441 on 15 September produced ash plumes that rose 1.8-2.2 km. During 15-17 September minor ashfall was reported in the municipalities of Cuernavaca, Valle de Chalco, Chiautla, Ixtapaluca, Nezahualcóyotl, La Paz, Ecatepec, Ayapango, Temamatla, Tenango del Aire, Tlalmanalco, Amecameca, Tepetlixpa, Tlalnepantla, and Acolman in the México State, and in Iztapalapa, Xochimilco, and Tlahuac in México City.

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

Soufriere St. Vincent – St. Vincent : National Emergency Management Organisation (NEMO) reported that activity at Soufrière St. Vincent had been low over the previous few months.

Suwanosejima – Ryukyu Islands (Japan) : JMA reported that the number of daily explosions at Suwanosejima’s Ontake Crater increased on 16 September and remained elevated through 20 September. Eruption plumes rose as high as 2.4 km above the crater rim and material was generally ejected 300 m away from the crater. Notably, explosions at 2014 on 16 September and at 0212 on 17 September ejected material almost 1 km S and SE, respectively.

Volcanos

Roundup of Global Volcanic Activity – New Activity for the Week 15 September – 21 September 2021

La Palma – Spain : An eruption began at La Palma after about a week of intensifying seismicity that showed hypocenters becoming shallower and moving NW, and significant related inflation. During 17-18 September the PEVOLCA (Plan de Emergencias Volcánicas de Canarias) steering committee (comprised of representatives from multiple agencies, local authorities, and institutions) reviewed mitigation, evacuation, and emergency plans. Helicopter and drone overflights were conducted in areas thought to be at risk from an eruption. IGN reported that during 17-18 September seismicity decreased, though an M 2 felt by local residents was located at 100 m depth, and vertical deformation occurred near the earthquake epicenters. IGN noted that seismicity intensified during the morning of 19 September, with earthquakes located at 0-6 km depth; a M 4.2 event was recorded at 1116 and vertical deformation increased. Authorities evacuated about 50 residents with reduced mobility and their companions from Las Manchas de Abajo, Jedey, San Nicolás and El Paraíso (El Paso and Los Llanos de Aridane), El Charco (Fuencaliente), La Bombilla (Los Llanos de Aridane and Tazacorte), and El Remo and Puerto Naos (Los Llanos de Aridane). Residents in an area prone to landslides were also evacuated. Other preparations continued at the hospital, in neighborhoods, and at evacuation centers. At 1510 on 19 September an eruption began in the area of Cabeza de Vaca, in the municipality of El Paso. Observers near the eruption site observed a large explosion that ejected material and produced a gas-and-ash plume; volcanic tremor was recorded by the seismic network. Two 200-m-long fissures aligned N-S opened about 200 m apart. INVOLCAN scientists observed seven vents along the fissures during the initial stage of the eruption. Multiple tall lava fountains fed flows downslope to the W, igniting forest fires. Photos and video posted by IGN showed multiple pulsating fountains fanning out from parts of the fissure. Ash plumes rose about 1.5 km and gas plumes rose 3 km and drifted ESE. The PEVOLCA steering committee briefly raised the Alert Level to Orange, and then to Red (the highest level on a four-color scale) by 1700 for high-risk municipalities directly affected by the eruption. About 5,500 people evacuated with no injuries reported, and authorities recommended that residents stay at least 2 km from the vents. The La Palma airport briefly closed, livestock were evacuated, and education centers were closed along with sections of multiple highways. Later that day INVOLCAN scientists who measured an area of the flows determined an average flow rate of 700 m per hour and temperatures around 1,075 degrees Celsius. By the next day a main cone had formed. The sulfur dioxide gas emission rate was 6,000-11,500 tons per day during 19-20 September. Satellite data showed a plume of sulfur dioxide drifting 475 km SE and reaching the coastline of Africa by 20 September. A map produced on 20 September by IGN in partnership with Copernicus Emergency Management Service (EMS) showed that the main part of the lava flow had traveled more than 3 km W and another branch extended about 1.5 km WSW. The flows had covered about 1 square kilometer and destroyed an estimated 166 buildings. A news article noted that activity was concentrated at four main vents, the last (and ninth) of which opened at 1956 on 20 September about 900 m from the main vents. Strong lava fountaining continued during 20-21 September and ash fell in the vicinity of the vents. Ash plumes rose 2.4-4.6 km (8,000-15,000 ft) a.s.l. and drifted as far as 55 km SW and S according to the Toulouse VAAC. Sulfur dioxide gas plumes drifted W and E at an altitude of 3 km (10,000 ft) a.s.l. By 0814 on 21 September an updated Copernicus EMS map showed that 350 homes had been covered by lava and the flow field had expanded to 1.54 square kilometers. According to a news report lava up to 12 m thick was advancing at a rate of 200 m per hour. A few hundred more residents evacuated as lava advanced towards Tacande; bringing the number of evacuees to about 5,700. The S lava branch was advancing slowly, at a rate of 2 m per hour. Later that day INVOLCAN stated that increased volcanic tremor amplitude reflected greater intensity of Strombolian explosions at the vents.

Semisopochnoi – Aleutian Islands (USA) : AVO reported that eruptive activity at Semisopochnoi’s North Cerberus crater continued during 15-21 September. Weather clouds obscured views of the volcano on most days. Several small daily explosions were recorded by local seismic stations; ash plumes were not visible in satellite images suggesting that they remained below 3 km (10,000 ft) a.s.l. and did not rise above the cloud deck. Overnight during 18-19 September small, discontinuous, low-level ash plumes were visible drifting 100 km SE. Ash emissions increased in frequency and intensity on 19 September. Ash clouds rose as high as 4.6 km (15,000 ft) a.s.l. and continued to drift 100 km SE. Sulfur dioxide emissions increased in the afternoon. AVO raised the Aviation Color Code to Red and the Volcano Alert Level to Warning at 2158. Explosions continued overnight and the next day, and ash plumes rose up to 4.6 km a.s.l. Plumes drifted 100 km NW. At 2012 on 20 September AVO lowered the Aviation Color Code to Orange noting the frequency of discrete explosions had decreased to a rate of about one per hour, though ash plumes from these events were still rising to 4.6 km a.s.l. and drifting NW. Sulfur dioxide plumes drifted N during 20-21 September.

Volcanos

Roundup of Global Volcanic Activity – Ongoing Activity for the Week 8 September – 14 September 2021

Aira – Kyushu (Japan) : JMA reported that incandescence from Minamidake Crater (at Aira Caldera’s Sakurajima volcano) was visible at night during 6-10 September. Deformation data showed inflation beginning at around 0300 on 13 September.

Cerro Hudson – Chile : SERNAGEOMIN lowered the Alert Level for Cerro Hudson to Green (the lowest level on a four-color scale) on 7 September, based on decreased activity. Neither morphological changes nor thermal anomalies were visible in satellite images or webcam views during 16-31 August. Seismicity remained low and sulfur dioxide emissions were not recorded.

Ebeko – Paramushir Island (Russia) : According to volcanologists in Severo-Kurilsk (Paramushir Island), about 7 km E of Ebeko, explosions during 4 and 6-8 September produced ash plumes that rose as high as 2 km (6,600 ft) a.s.l. and drifted N, S, and E. Ash fell in Severo-Kurilsk on 6 and 8 September.

Great Sitkin – Andreanof Islands (USA) : AVO reported that lava effusion continued at Great Sitkin during 7-14 September, though weather clouds often prevented webcam and satellite views. Seismicity remained elevated and was characterized by small earthquakes consistent with lava effusion. A radar image from 9 September indicated that the lava dome had grown to 1,100 m E to W and 860 m N to S, and was 25-30 m thick. Lava began to advance though a gap in the S rim of the summit crater. Elevated surface temperatures were visible in satellite data on 14 September.

Grimsvotn – Iceland : Icelandic Meteorological Office (IMO) reported that the jökulhlaup from the eastern and western parts of Grímsvötn’s caldera that began on 1 September had decreased during 8-10 September. IMO warned of continuing flood conditions in the downstream parts of the Skaftá river.

Ibu – Halmahera (Indonesia) : PVMBG reported that during 7-12 September gray-and-white ash plumes from Ibu rose 200-800 m above the summit and drifted N and W.

Karymsky – Eastern Kamchatka (Russia) : KVERT reported that a thermal anomaly over Karymsky was identified in satellite images during 3-10 September. Ash plumes rose 4 km (13,100 ft) a.s.l. and drifted 165 km E during 2-6 and 9 September.

Krysuvik-Trolladyngja – Iceland : The fissure eruption in the W part of the Krýsuvík-Trölladyngja volcanic system, close to Fagradalsfjall on the Reykjanes Peninsula, had paused for several days. The Institute of Earth Sciences reported that based on aerial photography acquired on 9 September, during the pause, the area of the flow field had grown to 4.6 square kilometers, and the total volume erupted was 143 million cubic meters. The crater floor was visible and was at least 70 m deep, with a deeper cavity or drainage sometimes visible. Lava visibly returned on 11 September; RSAM values increased and low lava fountains emerged from a few areas on the flow field to the W of the main crater. Lava also returned to the main vent. Lava fountains from the main crater were visible for periods of 5-10 minutes on 13 September and lava advanced in multiple directions. Lava flowed N on 14 September. By 15 September lava quickly advanced S, flowing past the earthen barriers constructed at the S end of Geldingadalur valley, and turning E into the Nàtthagi valley. The Aviation Color Code remained at Orange due to the lack of ash and tephra emissions, though IMO warned of the potential for lapilli and scoria fallout within a 650 m radius of the active vent. Authorities also warned of gas emission hazards.

Langila – New Britain (Papua New Guinea) : Based on analyses of satellite imagery and wind model data, the Darwin VAAC reported that during 11-12 September ash plumes from Langila rose to 2.1-2.4 km (7,000-8,000 ft) a.s.l. and drifted W. A thermal anomaly at the summit was identified in satellite data.

Lewotolok – Lembata Island (Indonesia) : PVMBG reported that the eruption at Lewotolok continued during 7-14 September. White-and-gray plumes rose as high as 700 m above the summit and drifted NWW, SW, and S.

Merapi – Central Java (Indonesia) : BPPTKG reported that both of Merapi’s two lava domes, situated just below the SW rim and in the summit crater, continued to grow during 3-9 September. The SW dome grew 5 m taller and had an estimated volume of 1.55 million cubic meters and the summit lava dome grew 1 m wider and had an estimated volume of 2.85 million cubic meters. One pyroclastic flow traveled 2 km down the SW flank and as many as 129 lava avalanches traveled a maximum of 2 km SW. According to the Darwin VAAC ash plumes rose 3 km (10,000 ft) a.s.l. and drifted E on 9 September, based on satellite and webcam views.

Nevados de Chillan – Chile : SERNAGEOMIN reported continuing explosive and effusive activity at Nevados de Chillán’s Nicanor Crater during 16-31 August, though weather conditions often prevented visual confirmation. Explosions generated ash plumes that rose as high as 1.1 km above the crater rim and were denser towards the end of August. Crater incandescence was sometimes visible at night, and though not intense, it brightened during explosive periods. The L5 and L6 lava flows continued to advance, though at a very low rate, averaging 1 m/h for L5. The L5 lava flow was 1,380 m long and L6 was 850 m long based on satellite images, measured from the rim of Nicanor Crater to the distal end of the flows. A decrease in thermal anomalies over the flows identified in satellite images suggested that the flows were cooling. The average temperature was 73 degrees Celsius with a maximum of 100 degrees for L5 and an average of 79 degrees Celsius with a maximum of 100 degrees for L6. Temperatures at the vents at Nicanor Crater averaged 115 degrees Celsius and were as high as 252 degrees during explosive phases. Sulfur dioxide emissions measured from local DOAS stations abruptly decreased and remained low. There was a total of five thermal anomalies, all with low radiance values. On 29 August pyroclastic flows traveled 560 m NE and collapses of L5’s middle and distal parts of the flow were observed.

Pavlof – United States : AVO reported that seismicity at Pavlof continued at low levels during 7-14 September and was interspersed with periods of more energetic tremor. Although weather clouds often obscured views, a series of four very minor ash emissions were visible in webcam images for a period of five hours on 10 September. The explosions produced minor and diffuse ash emissions that rose from a vent on the E flank and dissipated within minutes. A small explosion was recorded on 12 September and on 13 September, though cloud cover prevented visual confirmation of both events.

Semisopochnoi – Aleutian Islands (USA) : AVO reported that eruptive activity at Semisopochnoi’s North Cerberus crater continued during 7-14 September. Seismicity was elevated and characterized by periods of continuous tremor. Short-lived explosions lasting several minutes were detected daily in infrasound data. Small ash clouds from the explosions rose 3-4.6 km (10,000-15,000 ft) and dissipated within two hours. Sulfur dioxide emissions were detected in satellite images at altitudes less than 3 km (10,000 ft) a.s.l., sometimes extending downwind for hundreds of kilometers. During 7-9 September periods of lower-altitude ash emissions interspersed with voluminous steam plumes were observed in web camera images moving horizontally by the wind and rising no higher than 1.5 km (5,000 ft) a.s.l.

Sheveluch – Central Kamchatka (Russia) : KVERT reported that a bright thermal anomaly over Sheveluch was identified in satellite images during 3-10 September. The Kamchatka Branch of Geophysical Services (KBGS; Russian Academy of Sciences) Kamchatka volcano station reported that tourists visiting the volcano on 8 September experienced ashfall; weather conditions prevented views of summit. The next day they saw a small pyroclastic flow and that night saw crater incandescence and small incandescent avalanches traveling SE.

Suwanosejima – Ryukyu Islands (Japan) : JMA reported that four explosions at Suwanosejima’s Ontake Crater produced eruption plumes that rose as high as 3.3 km above the crater rim during 3-10 September. Large volcanic bombs were ejected 500 m from the crater. Crater incandescence was visible nightly.

Taal – Luzon (Philippines) : PHIVOLCS reported that gas-and-steam plumes from Taal rose as high as 2.5 km above the lake during 8-14 September and drifted NE, SE, S, and SW. Sulfur dioxide emissions were 5,246-11,840 tonnes/day during 9-10 and 12-13 September.

Volcanos

Roundup of Global Volcanic Activity – New Activity for the Week 8 September – 14 September 2021

Askja – Iceland : On 9 September IMO raised the Aviation Color Code for Askja to Yellow, noting that inflation that began in early August was ongoing and notably rapid. The uplift was centered at the W edge of Oskjuvatn caldera, which rose a total of 7 cm. The data suggested that magma was accumulating at 2-3.5 km depth.

Fukutoku-Oka-no-Ba – Volcano Islands (Japan) : The Japan Coast Guard reported that during a 12 September overflight of Fukutoku-Oka-no-Ba, observers noted that the W island was unchanged while the E side had been completely eroded and submerged. Yellow-green to yellow-brown discolored water extended from the vent area to the SW, S, and SE, suggesting continuing eruptive activity. Another area of discolored water had an approximate diameter of 2 km and was about 2 km ENE of the volcano. The discolored water prompted JMA to issue a navigation warning to nearby vessels.

La Palma – Spain : Instituto Volcanológico de Canarias (INVOLCAN) reported that a seismic swarm beneath Cumbre Vieja at the S part of La Palma began at 1618 on 11 September and was likely associated with a magmatic intrusion. The swarm intensified in number of events and magnitude, and by 1600 on 12 September a total of 315 earthquakes had been recorded and ranged 8-13 km in depth. The largest event was a M 2.8 (on the Mb_lg scale). On 13 September a scientific committee comprised of representatives from multiple agencies and institutions raised the Alert Level to Yellow (the second lowest level on a four-color scale) for the municipalities of El Paso, Los Llanos de Aridane, Mazo, and Fuencaliente de la Palma. By 0800 on 14 September 2,935 earthquakes had been detected. Larger events were felt by residents during 13-14 September; the largest earthquake was a M 3.9, recorded at 0600 on 14 September. Overall, the events were becoming shallower (8-10 km) and hypocenters migrated slightly to the W. GPS and tiltmeter networks showed deformation totaling 1.5 cm centered over the clusters of epicenters. INVOLCAN noted that 10 seismic swarms have been detected at La Palma since 2017; one in 2017, one in 2018, five in 2020, and three in 2021. The earthquakes in the previous swarms were deeper, between 20 and 30 km, and were less intense than the current swarm.

Pagan – Mariana Islands (USA) : The U.S. Geological Survey reported that emissions of ash and sulfur dioxide from Pagan were last detected on 6 September, though robust steam plumes occasionally continued to be visible at least through 14 September.

Whakaari/White Island – North Island (New Zealand) : On 14 September GeoNet reported that intermittent ash emissions at Whakaari/White Island continued to be visible during the previous week. Vigorous fumarolic plumes from the active vent area sometimes carried minor amounts of ash downwind at low altitudes and occasionally deposited ash on the island. Periods where ash was visible in the emissions did not correspond to explosive seismic or acoustic signals, suggesting that the ash was produced by weak wall fragments falling into the gas stream through the active vents and not from eruptive activity. Seismicity was characterized by low levels of volcanic tremor and occasional volcanic earthquakes.

Volcanos

Roundup of Global Volcanic Activity – Ongoing Activity for the Week 1 September – 7 September 2021

Ebeko – Paramushir Island (Russia) : According to volcanologists in Severo-Kurilsk (Paramushir Island), about 7 km E of Ebeko, explosions during 28-29 August produced ash plumes that rose as high as 1.9 km (6,200 ft) a.s.l. and drifted SE and E.

Fuego – Guatemala : INSIVUMEH reported that 7-15 explosions per hour were recorded during 31 August-7 September at Fuego, generating ash plumes as high as 1.1 km above the crater rim and shock waves that often rattled buildings around the volcano. Ash plumes mostly drifted as far as 15 km SW, W, NW, and N, causing daily ashfall in several areas downwind, including Morelia (9 km SW), Panimaché I and II (8 km SW), Santa Sofía (12 km SW), Yucales (12 km SW), El Porvenir (8 km ENE), Finca Palo Verde, Sangre de Cristo (8 km WSW), and San Pedro Yepocapa (8 km NW). Block avalanches descended the Ceniza (SSW), Seca (W), Trinidad (S), Taniluyá (SW), Las Lajas (SE), and Honda drainages, often reaching vegetated areas. Explosions ejected incandescent material 100-350 m above the summit on most days. On 1 September lahars descended the SE, S, and SW flanks (the Las Lajas, El Jute, and Seca drainages), carrying fine material along with tree branches and blocks 2 m in diameter. Lahars descended the El Jute, Las Lajas, and Ceniza drainages during 6-7 September.

Great Sitkin – Andreanof Islands (USA) : AVO reported that elevated surface temperatures at Great Sitkin and daily small earthquakes were detected during 31 August-7 September, consistent with the growing lava dome. Gas plumes were observed almost daily in satellite data.

Grimsvotn – Iceland : On 1 September the Icelandic Meteorological Office (IMO) stated that the water level of the Skaftá river at Sveinstindur (the closest gauging station at 28 km downstream from the ice margin) rose, suggesting the beginning of a Skaftárhlaup or glacial outburst flood (also called a jökulhlaup), that originated from Grímsvötn’s Western Skaftá caldera. A sulfur odor was also noted in the vicinity of Skaftá and Hverfisfljót. IMO warned that hydrogen sulfide released from the floodwater as it drained from the caldera lake was particularly potent at the river outlet from the ice margin, where concentrations may reach toxic levels. The flow rate in the Skaftá peaked at 520 cubic meters per second downstream near the bridge at Eldvatn on 2 September and then declined to 412 cubic meters per second in the afternoon of 3 September. As a result, the ice shelf began to subside around 2300 on 4 September, dropping 1 m by 1145 the next morning, based on GPS data. On 6 September the discharge rate increased rapidly and peaked at 610 cubic meters per second at 1400, then declined later that day. Data suggested that the peak discharge rate on 6 September was due to a second release of water from the eastern part of the caldera lake. On 7 September the flow rate had increased to 520 cubic meters per second. Based on an overflight IMO concluded that the glacial flooding from both the E and W parts of the lake was smaller in volume and flow rates compared to a similar event in 2018.

Karymsky – Eastern Kamchatka (Russia) : KVERT reported that ash plumes from Karymsky were visible in satellite images drifting 50 km NE and E during 26-27 August, and a thermal anomaly over the volcano was visible every day during 26 August -2 September except for on 29 August.

Krysuvik-Trolladyngja – Iceland : The fissure eruption in the W part of the Krýsuvík-Trölladyngja volcanic system, close to Fagradalsfjall on the Reykjanes Peninsula, paused on 2 September. Steam-and-gas emissions were seen rising from the crater during 2-7 September.

Lewotolok – Lembata Island (Indonesia) : PVMBG reported that the eruption at Lewotolok continued during 31 August-7 September. White and gray plumes rose as high as 600 m above the summit and drifted W and NW. Rumbling and banging were heard on most days. Incandescent material was ejected 300 m on 1 September, as far as 1 km SE during 4-5 September, and 200 m during 6-7 September.

Merapi – Central Java (Indonesia) : BPPTKG reported that both of Merapi’s two lava domes, situated just below the SW rim and in the summit crater, continued to grow during 27 August-2 September. The SW dome grew 2 m taller and had an estimated volume of 1.44 million cubic meters and the summit lava dome grew 1 m taller and had an estimated volume of 2.84 million cubic meters. A total of six pyroclastic flows descended the SW flank as far as 2.5 km; as many as 80 lava avalanches traveled a maximum of 2 km SW.

Popocatepetl – Mexico : CENAPRED reported that each day during 31 August-7 September there were 66-102 steam-and-gas emissions from Popocatépetl. Cloudy weather often prevented views of the volcano. Crater incandescence was visible during the morning of 1 September and explosions were recorded at 2135, 2254, and 2345 later that same day. The Washington VAAC noted that ash plumes rose to 5.8-6.1 km (19,000-20,000 ft) a.s.l. and drifted NW and W during 5-6 September based on satellite and webcam views. Explosions were recorded by CENAPRED at 1642 on 5 September and 0820 on 6 September. Emissions had a low ash content during 6-7 September; explosions occurred at 0212 and 0414 on 7 September.

Semeru – Eastern Java (Indonesia) : PVMBG reported that at 0544 on 2 September an observer saw an ash plume from Semeru rising 200 m above the summit and drifting SW. At 0549 on 6 September an ash plume rose 500 m and drifted N.

Semisopochnoi – Aleutian Islands (USA) : AVO reported that eruptive activity at Semisopochnoi’s North Cerberus crater continued during 31 August-7 September. Multiple daily explosions were detected by seismic and infrasound networks. Ash-and-steam plumes from the explosions were sometimes confirmed in satellite and webcam images rising to altitudes lower than 3 km (10,000 ft) a.s.l., though during 6-7 September ash plumes rose as high as 4.6 km (15,000 ft) a.s.l. Local ashfall on the island was visible in satellite data. Sulfur dioxide emissions were detected in satellite images during 31 August-2 September and on 6 September.

Sheveluch – Central Kamchatka (Russia) : KVERT reported that a thermal anomaly over Sheveluch was identified in satellite images during 27 August-3 September. A gas-and-steam plume with some ash was visible in satellite data drifting 54 km NE and NW on 26 and 28 August.

Suwanosejima – Ryukyu Islands (Japan) : JMA reported that three explosions at Suwanosejima’s Ontake Crater produced eruption plumes that rose as high as 4.8 km above the crater rim during 27 August-3 September. Large volcanic bombs were ejected 700 m from the crater. Crater incandescence was visible nightly and ashfall was often reported in Toshima village (4 km SSW).

Telica – Nicaragua : INETER reported that at 0525 on 1 September an explosion at Telica produced an ash plume that rose 250 m above the crater rim and drifted N and NW. Emissions periodically continued later that day, without explosions, and caused minor ashfall in areas to the NW, W, and SW including in the communities of Aguas Frías, San Pedro Nuevo, and Las Marías (7 km NNW).

Volcanos

Roundup of Global Volcanic Activity – New Activity for the Week 1 September – 7 September 2021

Askja – Iceland : On 3 September IMO reported that inflation at Askja had begun in early August based on ground deformation data derived from satellite images and continuous GPS data. The uplift was centered at the W edge of Oskjuvatn caldera and vertically deformed at a rate of about 5 cm per month. Data indicated that the source of the inflation was at a depth of about 3 km and caused a volume change of about 0.01 cubic kilometers per month; the source was unknown, though most likely was caused by an influx of magma.

Kilauea – Hawaiian Islands (USA) : HVO reported that ground deformation beneath the S part of Kilauea’s summit ceased on 30 August and the earthquake rate decreased during 30-31 August. The data suggested that a magma intrusion had slowed or stopped. Earthquake rates and ground deformation remained near pre-intrusion levels through 7 September.

Pagan – Mariana Islands (USA) : Continuous gas-and-ash plumes from Pagan were observed in satellite images for most of 1 September, prompting the USGS to raise the Aviation Color Code and the Volcano Alert Level remained at Orange/Watch, respectively. The plumes drifted 150 km NW and SW at an altitude of 3 km (10,000 ft) a.s.l. The emissions briefly paused at 2300 and then resumed; satellite images acquired the next morning, on 2 September, showed gas-and-ash plumes drifting 650 km. A plume of ash and sulfur dioxide was identified in satellite data, drifting 150 km W at an altitude of 1.2 km (4,000 ft) a.s.l. early on 3 September. Ash deposits in and around the crater and on downwind parts of the island were observed in 4 September images. During 4-6 September gas-and-ash plumes rose to 1.5 km (5,000 ft) a.s.l. and drifted at least 400 km W. Sulfur dioxide emissions were observed in satellite data on 6 September; ash emissions paused sometimes during 6-7 September as activity declined. A robust steam plume possibly containing a minor amount of ash was visible in satellite data on 7 September drifting 24 km W at an altitude of 1.5 km (5,000 ft) a.s.l.

Pavlof – United States : AVO reported that seismicity at Pavlof was low, though elevated above background levels during 31 August-7 September. Inclement weather sometime prevented satellite and webcam views of the volcano. A sulfur dioxide plume was visible in satellite images on 2 September.

Whakaari/White Island – North Island (New Zealand) : GeoNet reported that beginning at 0630 on 2 September minor ash emissions from the active vent at Whakaari/White Island were visible in webcam images. The emissions were observed in satellite images drifting SW and reaching the Bay of Plenty coastline. GeoNet noted that short episodes of minor ash emissions had been recorded during the previous few weeks, though none were as sustained as the 2 September episode. Minor ash emissions were also recorded on 3 September, but then ceased. The webcam continued to record nighttime incandescence from the vent, at least through 6 September, suggesting that temperatures were likely 500-600°C. Steam-and-gas plumes were voluminous, and coupled with weather conditions, were easily visible from the coast. Deformation measurement showed a broad area of subsidence around the vent area, possibly from the release of pressurized gas at depth and the more voluminous plumes. Additionally, the ash emissions may have possibly been caused by wall fragments falling into the vent.