Roundup of Global Volcanic Activity – New Activity for the week 23 November – 29 November 2022
Ahyi – Mariana Islands (USA) : Signs of unrest at Ahyi Seamount have been observed in satellite and remote geophysical data, starting in mid-October. Hydroacoustic signals continued to be observed but had declined in the previous few weeks. Discolored water over the seamount was first visible on 18 November and persisted, possibly from either degassing or an eruption.
Cotopaxi – Ecuador : On 22 November IG concluded that the minor ash emissions recorded at Cotopaxi on 21 October were due to magma in the volcano’s conduit, though not from new magma entering the system after the 2015 eruption. An average of one seismic event per day was recorded based on long-term seismic rates. In the months prior to the 21 October event, the rate had gradually increased to 1.5 events per day, though after the ash emission the rate fell back to one event per day. Most of the seismicity was located beneath the summit. Minor deformation was recorded during August-November, but it could not be conclusively linked to the eruptive activity. Sulfur dioxide emissions increased in October and gas-emission analysis indicated a magmatic origin. Nearly continuous emissions of gas-and-steam had been rising from the main crater since 21 October, as high as 2 km above the rim. The heights of emissions averaged 200 m and were as high as 800 m in 2021. At 1848 on 25 November the seismic network recorded a tremor signal associated with a gas emission that drifted NNW. At approximately 0310 on 26 November a new episode of tremor was associated with a gas-and-ash emissions that lasted for several hours. The plume drifted 85 km NNW, passing over Quito (55 km N), and caused ashfall in El Pedregal (60 km N), Tambillo (32 km NNW), Guamaní (42 km NNW), Amaguaña (33 km NNW), Chillogallo (44 km NNW), Quitumbe (41 km NNW), Solanda (46 km NNW), Lloa (48 km NNW), Conocoto (41 km N), Mercado Mayorista (45 km NNW), Villaflora (47 km NNW), and Rumipamba (55 km N). Moderate levels of seismic tremor were recorded until about 1050.
Etna – Sicily (Italy) : INGV reported that at about 1800 on 27 November a vent opened at the NE base of Etna’s SE Crater, at 2,800 m elevation, and produced a lava flow. The flow slowly advanced a few hundred meters towards the Valle del Leone. Tremor levels at the time the vent opened showed no variations from the average trend recorded during the previous week, and no notable changes were identified in deformation data. Effusive activity continued through 30 November, with additional small lava flows emplacing over the first one. For a period of about an hour, beginning at 1700 on 29 November, tremor amplitude increased and then peaked; the amplitude fluctuated between medium and high values for a few hours afterwards. The source of the tremor was in an area between the SE Crater and Bocca Nuova Crater, at elevations of 2,000-2,600 m.
Klyuchevskoy – Central Kamchatka (Russia): On 24 November KVERT reported that the Strombolian eruption that had begun at Klyuchevskoy on 16 November was ongoing. Lava fountaining at the summit was visible and a thermal anomaly over the summit was identified in satellite images during 17-20 and 24 November.
Mauna Loa – Hawaiian Islands (USA) : An eruption at Mauna Loa began at about 2330 on 27 November in Moku‘aweoweo, the summit caldera. A thermal anomaly and a plume of sulfur dioxide gas were identified in satellite images at the onset of the eruption, according to NOAA’s National Environmental Satellite, Data, and Information Service (NESDIS). Hawai‘i Volcanoes National Park closed the summit area to visitors. Lava erupted from a fissure in the caldera and by 0127 on 28 November lava had overflowed the caldera walls. During an overflight at about 0630 scientists confirmed that the eruption had moved from the summit to the Northeast Rift Zone, where three fissures opened at a high elevation. The fissures fed several lava flows that traveled N and NE; the flows were active in the “saddle” area between Mauna Loa and Mauna Kea and were not threatening any populated areas. Lava fountains along the fissures were as tall as 30-60 m, though most were only a few meters tall. Lava flows from fissures 1 and 2 traveled downslope and stalled about 18 km from the Saddle Road; the two fissures were inactive by 1330. Sulfur dioxide emissions were approximately 250,000 tonnes per day. Fissure 3, at the lowest elevation of the NE fissures, issued the longest lava flows. Lava flows crossed the Mauna Loa Weather Observatory Road at about 2000 on 28 November; by 0700 on 29 November the flow front was about 10 km from the Saddle Road. Lava fountains at Fissure 3 were 25 m high in the morning on 29 November but had grown to 40-50 m tall in the afternoon. Fissure 4, downslope of Fissure 3, opened at about 1930 and produced lava fountains that rose 5-10 m high. There was no activity in the summit caldera, nor along the Southwest Rift Zone. Gas plumes from the activity drifted N.
San Miguel – Eastern El Salvador : MARN reported that the eruption at San Miguel continued during 23-28 November. Daily phreatic explosions produced gas, steam, and ash emissions that generally rose around 500 m above the crater rim. There were a total of 188 events recorded by 28 November, with a daily average of 13. The explosions were more energetic mid-week; explosions at 1302 and 1642 on 26 November and 0718 and 0802 on 27 November ejected hot rocks onto the flanks and produced eruption plumes that rose as high as 1.1 km above the summit. A cow was killed by hot ballistics during the morning of 27 November, according to a news article. El Director General de Protección Civil issued a Green Alert for the municipalities of Chinameca, San Rafael Oriente, and San Jorge, and warned the public to stay 3 km away from the volcano. The notice recommended that those living within a 3-6 km radius should identify evacuation routes and to take preparation measures as guided by the Sistema Nacional de Protección Civil. Sulfur dioxide emissions generally averaged 283 tons per day during 26-27 November, below the baseline of 300 tons per day. Specific measurements during explosive events revealed that the emissions were sometimes as high as 1,200 tons per day. MARN warned the public to stay 2 km away from the volcano, and for those living within a 2-5 km radius to identify evacuation routes and to take preparation measures as guided by the Sistema Nacional de Protección Civil.