Volcanos

Roundup of Global Volcanic Activity – Ongoing Activity for the Week 29 April 2020 – 5 May 2020

Aira | Kyushu (Japan) : JMA reported that during 27 April-4 May incandescence from Minamidake Crater (at Aira Caldera’s Sakurajima volcano) was visible nightly. An explosion at 2246 on 27 April generated an ash plume that rose over 3 km above the crater rim and ejected blocks 600-900 m from the crater. An eruptive event at 1510 on 2 May produced a plume that rose 1.4 km above the rim. 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 29 April-5 May ash plumes from Dukono rose to 2.1 km (7,000 ft) a.s.l. and drifted E and NE. 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) : Volcanologists in Severo-Kurilsk (Paramushir Island), about 7 km E of Ebeko, observed explosions during 24 April-1 May that sent ash plumes up to 3.5 km (11,500 ft) a.s.l. The plumes drifted E, causing ashfall in Severo-Kurilsk during 25-30 April. An ash cloud was identified in satellite data on 29 April drifting 180 km SE. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Klyuchevskoy | Central Kamchatka (Russia) : KVERT reported that Strombolian and Vulcanian activity at Klyuchevskoy was visible during 24 April-1 May along with a bright thermal anomaly identified in satellite images. Ash plumes drifted about 425 km W, and a lava flow continued to descend the Apakhonchich drainage on the SE flank. The Aviation colour Code remained at Orange.

Reykjanes | Iceland : IMO reported that uplift detected in the Thorbjorn area decreased in the beginning of April and stopped later in the month. Seismicity, which had occurred across three main volcanic systems: Eldey, Reykjanes-Svartsengi, and Krýsuvík, had significantly decreased. These data indicated that the injection of magma beneath Thorbjorn had stopped, though there were indications of deformation over a larger area. On 4 May the Aviation colour Code was lowered to Green.

Rincon de la Vieja | Costa Rica : OVSICORI-UNA reported two phreatic explosions at Rincón de la Vieja during 30 April-5 May and continuing fluctuations in tremor levels. At 1610 on 30 April an event produced a gas-and-steam plume that rose 1.5 km above the crater rim. At 1317 on 5 May a steam plume rose 200 m above the rim.

Ruapehu | North Island (New Zealand) : On 4 May GeoNet reported a cooling trend of the crater lake water at Ruapehu with a current temperature of 35 degrees Celsius. During February-April the water temperature had peaked at 42 degrees Celsius. The intensity of volcanic tremor had been weak during the past month after a peak in strength in early March; tremor had declined slowly almost in conjunction with the lake water cooling trend. During a visit to the lake the previous week volcanologists noted that the lake was a uniform gray colour with a few surface slicks and no obvious upwelling. Since that visit the water level had risen and was flowing into the upper Whangaehu River. The Volcanic Alert Level remained at 1 (minor volcanic unrest) and the Aviation colour Code remained at Green.

Semeru | Eastern Java (Indonesia) : PVMBG reported that the eruption at Semeru continued during 27 April-3 May. Eruptive events produced dense white-gray ash plumes that rose 100-400 m above the summit; white plumes rose as high as 200 m. Incandescent material from the ends of lava flows descended 1 km in the Kembar and Kobokan drainages (on the S flank), reaching a maximum distance of 2 km from the crater. 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.

Suwanosejima | Ryukyu Islands (Japan) : JMA reported that at 0432 on 28 April an eruption at Suwanosejima’s Ontake Crater produced a plume that rose 1.6 km above the crater rim and ejected blocks as far as 800 m from the crater. An explosion at 1214 on 29 April caused glass in an office building to vibrate in a village 4 km SSW. There was a total of 64 and 50 explosions recorded on 28 and 29 April, respectively; two explosions were detected on 30 April and one on 1 May. The Alert Level remained at 2 (on a 5-level scale).

Yasur | Vanuatu : On 30 April the Vanuatu Meteorology and Geo-Hazards Department (VMGD) reported that recent visual observations at Yasur confirmed that gas-and-ash emissions were ongoing. The report noted that some of the explosions could be intense and eject bombs outside of the summit crater. Data from the seismic network indicated a decrease in activity as compared to March data. The Alert Level remained at 2 (on a scale of 0-4). VMGD had increased the radius of the permanent exclusion zone to 600 m in mid-March and that remained in effect; residents and tourists were reminded that volcanic ash and gas could reach areas impacted by trade winds.

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