Roundup of Global Volcanic Activity – Ongoing Activity for the Week 22 April 2020 – 28 April 2020
Aira | Kyushu (Japan) : JMA reported that during 20-27 April incandescence from Minamidake Crater (at Aira Caldera’s Sakurajima volcano) was visible nightly. The seismic network recorded 11 eruptive events and five explosions. Ash plumes rose as high as 2.5 km above the crater rim and blocks were ejected as far as 1.1 km away from the crater. The Alert Level remained at 3 (on a 5-level scale).
Dukono | Halmahera (Indonesia) : Based on satellite and wind model data, the Darwin VAAC reported that during 22-28 April ash plumes from Dukono rose to 2.1 km (7,000 ft) a.s.l. and drifted in multiple directions. 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.
Ebeko | Paramushir Island (Russia) : KVERT reported that a thermal anomaly over Ebeko was identified in satellite images on 18 and 20 April. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).
Irazu | Costa Rica : OVSICORI-UNA reported that on 21 April scientists confirmed that the lake in Irazú’s crater was gone and noted continuous intra-crater landslides from unstable parts of the crater.
Klyuchevskoy | Central Kamchatka (Russia) : KVERT reported that Strombolian activity at Klyuchevskoy was visible during 17-24 April along with a bright thermal anomaly identified in satellite images. Gas-and-steam plumes with some ash rose to 6 km (19,700 ft) a.s.l. and drifted 470 km E. A lava flow began to descend the SE flank in the Apakhonchich drainage at 0607 on 19 April. The Aviation colour Code remained at Orange.
Nevado del Ruiz | Colombia : On 28 April Servicio Geológico Colombiano’s (SGC) Observatorio Vulcanológico y Sismológico de Manizales reported that small ash-and-gas emissions from Nevado del Ruiz were periodically visible in webcam images and observed by Parque Nacional Natural Los Nevados officials during the previous week. These emissions drifted WSW and NW. A gas-and-steam plume rose 1.2 km above the crater rim on 21 April. The Alert Level remained at 3 (Yellow; the second lowest level on a four-colour scale).
Pacaya | Guatemala : INSIVUMEH reported that during 22-28 April Strombolian explosions at Pacaya’s Mackenney Crater ejected material as high as 100 m above the crater rim. Lava flows were active during 26-27 April, traveling about 150 m SW. Seismicity increased at 2140 on 27 April, and a lava flow on the SW flank lengthened to 400 m. Later investigation of a linear “fuming area” on the NE flank identified a forest fire as the cause.
Reventador | Ecuador : IG reported that during 21-28 April seismic data from Reventador’s network indicated a high level of seismic activity, including explosions, long-period earthquakes, and signals indicating emissions. Gas, steam, and ash emissions were observed almost daily, though cloudy weather sometimes prevented views of the volcano; IG and the Washington VAAC reported gas-and-ash emissions rising as high as 1.3 km above the crater rim and drifting W, NW, N, and NE. Incandescent blocks rolled 500-800 m down the flanks in all directions during 21-24 and 26-27 April.
Rincon de la Vieja | Costa Rica : OVSICORI-UNA reported periodic phreatic explosions at Rincón de la Vieja during 22-28 April. At 0535 on 22 April a phreatic event was recorded by the seismic network; weather conditions prevented good visual observations, though a steam plume was seen rising 1.5 km above the crater rim. There were five events recorded by the seismic network during the morning of 24 April, with most producing steam-and-gas plumes that rose 300-500 m above the crater rim. The largest event, recorded at 1020, ejected water and solid material 300 m above the crater rim and a steam plume that rose 1 km. An event at 1547 on 26 April ejected sediment 200 m above the rim and plumes 300 m above the rim. A plume with no ash rose 1 km at 1720 on 27 April.
Santa Maria | Guatemala : INSIVUMEH reported that explosions at Santa María’s Santiaguito lava-dome complex generated ash plumes that rose 800-900 m above the crater and drifted as far as 1.2 km NW, W, and SW. Avalanches of blocks descended the S, SE, and E flanks of Caliente cone. Ashfall was recorded in areas downwind including Loma Linda, San Marcos Palajunoj, and La Florida and Santa Marta fincas.
Semeru | Eastern Java (Indonesia) : PVMBG reported that the eruption at Semeru continued during 22-28 April. Eruptive events produced dense gray ash plumes that rose as high as 500 m above the summit. Lava blocks traveled 300 m from the ends of lava flows in the Kembar drainage. The Alert Level remained at 2 (on a scale of 1-4), and the public was reminded to stay outside of the general 1-km radius from the summit and 4 km on the SSE flank.
Sheveluch | Central Kamchatka (Russia) : KVERT reported that a thermal anomaly over Sheveluch was identified in satellite images during 17-24 April, and a plume of re-suspended ash drifted 140 km NE on 18 and 20 April. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).
Suwanosejima | Ryukyu Islands (Japan) : JMA reported that during 17-24 April incandescence from Suwanosejima’s Ontake Crater was visible nightly. Small eruptions occasionally occurred, along with an explosion on 24 April, producing gray-white plumes that rose as high as 600 m above the crater rim and ejected material as far as 600 m from the crater. Rumbling sounds were noted in a village 4 km SSW. The Alert Level remained at 2 (on a 5-level scale).