Volcanos

Roundup of Global Volcanic Activity – New Activity for the week of 22 March-28 March 2017

Aira | Kyushu (Japan) : JMA reported that an explosion at Minamidake summit crater (at Aira Caldera’s Sakurajima volcano) detected at 1803 on 25 March generated a pyroclastic flow that traveled 1.1 km down the S flank. An explosion at 2228 produced an ash plume that rose 1.4 km above the crater rim. Ash fell in the vicinity of the volcano and as far as 4.5 km E. Based on JMA notices and satellite-image analyses, the Tokyo VAAC reported that ash plumes drifted SE and E that same day.

Bezymianny | Central Kamchatka (Russia) : KVERT reported that during 17-24 March lava continued to advance down the NW flank of Bezymianny’s lava dome. A thermal anomaly was visible in satellite images on 17, 19, and 22 March. The Aviation Colour Code remained at Orange.

Cerro Azul | Isla Isabela (Ecuador) : IG reported that increased seismicity at Cerro Azul began on 15 February and was characterized by the presence of volcano-tectonic events. A 1-hour-long swarm occurred the next day, and then afterwards only sporadic events were detected, some of which were located in the Sierra Negra volcano region. Sporadic events located at Sierra Negra continued to be detected during 8-13 March. A 30-minute-long swarm was recorded on 18 March. Earthquakes became more frequent and intense on 19 March, and another swarm occurred during 0700-1800 on 20 March; earthquake locations migrated SW, to the SE part of Cerro Azul during 19-20 March. Another swarm was detected during 1915-2200 on 21 March, with most magnitudes between 2.4 and 3, though the highest was 3.6. Deformation during 8-20 March was detected in satellite data, characterized by 14 cm of inflation at the SE flank and 11.2 cm of deflation at the summit. Deformation and seismic data suggested the emplacement of a sill 3.5-6.3 km below the SE flank.

Chirinkotan | Kuril Islands (Russia) : SVERT noted that no further activity at Chirinkotan was visible after the ash emission on 21 March. The Aviation Colour Code was lowered to Green (on a four-colour scale).

Manam | Papua New Guinea : Based on analyses of satellite imagery and model data, the Darwin VAAC reported that on 24 March a steam plume from Manam, possibly with a minor ash content, drifted 75 km SE.

Nevados de Chillan | Chile : On 24 March OVDAS-SERNAGEOMIN reported that during an overflight of Nevados de Chillán scientists observed a single 100-m-diameter crater, the result of two active craters merging together sometime between 7 and 15 March. In addition there were five explosions in the period of about an hour, ejecting tephra 900 m high which dispersed SE. The pattern of activity changed on 17 March with increased frequency and magnitude of the explosions. The Alert Level remained at Yellow, the middle level on a three-colour scale, and the public was reminded not to approach the craters within a 3-km radius.

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