Volcano World

BPPTKG summarized the eruption at Merapi (on Java) during 10-16 March, including the collapses at the SW lava dome that began on 11 March and continued through the week. A total of 68 pyroclastic flows traveled as far as 4 km down the Bebeng and Krasak drainages on the SW flank. The largest pyroclastic flows were recorded during 11-12 March, which caused ashfall of varying intensity in areas to the W, NW, and N including in Dukun District, Sawangan, Magelang Regency; Magelang City; Selo District, Boyolali Regency; Ambarawa, Jambu, Sumowono, Pringapus, Banyubiru, Bawen Districts, Semarang Regency. Morphological changes to the SW lava domes were evident in webcam and drone images. The volume of the dome before 11 March was 2,759,100 cubic meters and by 13 March the dome volume had decreased to 1,686,200 cubic meters, with an estimate volume loss of 1,072,800 cubic meters. The volume of the summit dome remained unchanged and was estimated at 2,312,100 cubic meters. According to the Darwin VAAC ash plumes were visible in webcam images on 15 and 17 March rising as high as 1.2 km above the summit and drifting S and W, respectively. On both days weather conditions prevented satellite image views. During 16-20 March BPPTKG reported 14-38 daily counts of lava avalanches with material descending the SW flank as far as 1.8 km. Daily counts were not available for 17 March, though incandescent avalanches were visible in webcam footage; rainy weather sometimes prevented visual observations. The Alert Level remained at 3 (on a scale of 1-4), and the public was warned to stay 3-7 km away from the summit based on location.

Sources: Balai Penyelidikan dan Pengembangan Teknologi Kebencanaan Geologi (BPPTKG),Darwin Volcanic Ash Advisory Centre (VAAC)

An 18 March satellite image of Nyamulagira showed a large thermal anomaly, possibly 600 m wide, in the summit crater, indicating that the eruption that had begun on 14 March was continuing.

Source: Sentinel Hub

AVO reported that low-level ash emissions from the N crater of Semisopochnoi?s Mount Young were observed in several web camera images during 18-19 March. Small explosions and volcanic tremor had also resumed. Ash emissions were not detected in satellite images, though on 18 March a robust steam-and-gas plume was visible drifting 150 km from the N crater. AVO raised the Volcano Alert Level to Watch (the second highest level on a four-level scale) and the Aviation Color Code to Orange (the second highest color on a four-color scale) on 19 March. Low-level seismicity continued during 20-21 March and one small explosion was detected in seismic and infrasound data. Clouds obscured webcam and satellite views.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

AVO reported that earthquake activity near Takawangha had decreased in both rate and magnitude from the peak of the swarm recorded during 9-11 March. More than 800 earthquakes, including multiple M2 and above events, were detected beneath Tanaga Island at depths less than 9 km below sea level during 11-17 March. The decline in activity decreased the potential for an eruption, so AVO lowered the Volcano Alert Level to Advisory (the second lowest level on a four-level scale) and the Aviation Color Code to Yellow (the second lowest color on a four-color scale) on 16 March. The Volcano Alert Level and Aviation Color Code for Tanaga (8 km W) were also lowered to the same level. Several M 2 and higher earthquakes were detected during 17-18 March, in addition to numerous smaller events. Earthquake activity persisted through 20 March.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

AVO reported that earthquake activity near Tanaga had decreased in both rate and magnitude from the peak of the swarm recorded during 9-11 March. More than 800 earthquakes, including multiple M2 and above events, were detected beneath Tanaga Island at depths less than 9 km below sea level during 11-17 March. The decline in activity decreased the potential for an eruption, so AVO lowered the Volcano Alert Level to Advisory (the second lowest level on a four-level scale) and the Aviation Color Code to Yellow (the second lowest color on a four-color scale) on 16 March. The Volcano Alert Level and Aviation Color Code for Takawangha (8 km E) were also lowered to the same level. Several M 2 and higher earthquakes were detected during 17-18 March, in addition to numerous smaller events. Earthquake activity persisted through 20 March.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

Unrest at Ahyi Seamount continued during 15-21 March. A total of three short (~30 seconds) hydroacoustic detections from the direction of Ahyi were detected by pressure sensors on Wake Island, 2,270 km E, during 17-19 March. Weather clouds often prevented satellite views. Data was not available during 20-21 March due to an outage, though a plume of discolored water was visible in satellite images. The Aviation Color Code remained at Yellow (the second lowest level on a four-color scale) and the Volcano Alert Level remained at Advisory (the second lowest level on a four-level scale).

Source: US Geological Survey

JMA reported ongoing eruptive activity at Minamidake Crater (at Aira Caldera?s Sakurajima volcano) during 13-20 March, with crater Incandescence visible nightly. Sulfur dioxide emissions were high at 2,100 tons per day on 13 March. On 14 March an explosion produced an ash plume that rose 1 km above the crater rim. Three eruptive events were recorded during 17-20 February, producing volcanic plumes that rose as high as 1 km. No activity or crater incandescence was detected at Showa Crater. The Alert Level remained at 3 (on a 5-level scale), and residents were warned to stay 2 km away from both craters.

Source: Japan Meteorological Agency (JMA)

IG reported that eruptive activity at Cotopaxi was ongoing during 15-21 March. Gas-and-steam emissions were visible on most days rising as high as 1 km above the crater rim and drifting in multiple directions. On 16 March several gas emissions containing minor amounts of ash rose as high as 1.5 km and drifted SE. During 19-20 March ash-and-gas plumes rose 1-1.5 km and drifted E and SE. Servicio Nacional de Gestin de Riesgos y Emergencias (SNGRE) maintained the Alert Level at Yellow (the second lowest level on a four-color scale).

Sources: Instituto Geofsico-Escuela Politcnica Nacional (IG) ,Servicio Nacional de Gestin de Riesgos y Emergencias (SNGRE)

PVMBG reported that white-and-gray plumes of variable densities rose from Dukono as high as 450 m above the summit and drifted N and W during 15-16, 18, and 20 March. No plumes were observed on 17 March, but white steam-and-gas plumes rose 150 m and drifted W on 19 March. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to remain outside of the 2-km exclusion zone.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)

KVERT reported that moderate activity at Ebeko was ongoing during 9-16 March. According to volcanologists in Severo-Kurilsk (Paramushir Island, about 7 km E) explosions during 10-12 March generated ash plumes that rose as high as 3.5 km (11,500 ft) a.s.l. and drifted NE and NW. A thermal anomaly was identified in satellite images on 10 and 13 March. The Aviation Color Code remained at Orange (the second highest level on a four-color scale). Dates are based on UTC times; specific events are in local time where noted.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)