Volcanos

Roundup of Global Volcanic Activity

Bulusan (Luzon Island, Philippines): A sudden eruption occurred this morning (at 11:35 local time). An explosion generated an ash plume that rose about 2000 m above the volcano's summit and drifted northwest, causing light ash falls in nearby downwind areas. According to PHILVOLCS, the eruption preceded by a seismic swarm with more than 100 small earthquakes and lasted 5 minutes. The eruption itself was only steam-driven - no magma itself has reached the surface,- and caused by explosion of over-pressurized and over-heated fluids from the volcano's strongly developed hydrothermal system. A similar explosion had occurred on 21 February. Following it, scientists monitoring the volcano have been seeing an inflation of the edifice (swelling of the ground) since May, probably caused by magma intruding at depth. This would have been providing new energy (heat) to the system and cause increasing instability. Bulusan's official status remains unchanged at "Alert Level 1 (abnormal)" on the scale of 0 (normal) to 5 (highest).

Sinabung (Sumatra, Indonesia): The eruption of the volcano continues with little changes: viscous magma is accumulating at the summit lava dome and forms over-spilling lobes on the southeastern slope that are prone to collapse. Trapped gasses produce occasional vertical explosions with ash plumes that reach 1-2 km height mostly. The mass of new lava emplaced in unstable positions has again reached critical values, and might be producing new pyroclastic flows soon. After the last big pyroclastic flow which devastated the village of Gamber on 21 May and killed 9 people there, the new lava dome has been growing, forming a (new) lava lobe that has been becoming longer each day. According to the observatory post, Sinabung has been effusing lava at a rate of approx. 300.000 cubic meters per day and by now, a volume of 1,5 million cubic m is hanging on the unstable southeastern upper flank (in the new lobe).

Manam volcano (Papua New Guinea): Mild eruptive activity likely continues at the volcano. Satellite images show a thermal hot spot at the summit crater and occasionally, during clear weather, strong emissions of sulphur dioxide gas. Due to the lack of current field observations, no detailed information about the nature of the activity (if any) is currently available. The most likely situation is that there are mild strombolian eruptions and/or a growing lava dome at the summit crater. Manam is one of the region's most active volcanos.