Volcanos

Roundup of Global Volcanic Activity

Kliuchevskoi (Kamchatka): The effusive-explosive eruption continues with no significant changes. The lava flow on the upper eastern flank remains well alimented while (strombolian) explosive activity has been low during the past days.

Shiveluch (Kamchatka): The volcano’s activity has been comparably low recently, but continues as viscous lava rises and accumulates at the active lava dome. A small collapse occurred yesterday evening, triggering a pyroclastic flow on the SW flank of the dome and producing an ash plume that rose to approx. 3.5 km above sea level. KVERT warns that “ash explosions up to 32,800 ft (10 km) a.s.l. could occur at any time. Ongoing activity could affect international and low-flying aircraft.”

Manam (Papua New Guinea): Darwin VAAC reported a small ash plume visible on satellite imagery extending 10 nautical miles west from the small island this morning. A moderate thermal anomaly from the volcano has been present, and become stronger during June-July, during the past months as well. This suggests that mild eruptive activity, perhaps the slow growth of a lava dome at the summit, with sporadic explosions continues.

Alaid (Northern Kuriles): The new eruptive phase at the remote volcano which had started around 4 July, after a possible pause in activity, continues with dominantly effusive activity. A recent satellite image allows to determine that fresh lava flows have erupted (or still are erupting) from the summit vent(s) and accumulate in the northern part of the summit caldera. Judging from the attached high-resolution satellite image, it seems likely that the main vent, a cinder cone that has been forming since the start of the recent eruption last October, remains active, likely with strombolian activity, while the lava flows themselves originate from two (?) flank vents at its northern feet.

Sinabung (Sumatra, Indonesia): Explosions of small to moderate size remain relatively frequent at the volcano. A stronger one occurred yesterday morning at 09:24 local time, generating an ash column that rose 3000 m above the summit.

Dukono (Halmahera): The volcano continues to erupt more or less continuous low levels ash plumes (7-10,000 ft altitude) that drift in various directions before dissipating.

Masaya (Nicaragua): The lava lake in the Santiago crater remains active, but has dropped a bit recently.

Turrialba (Costa Rica): Activity of the volcano has remained more or less unchanged during the past weeks. The western crater continues to produce intermittent (every few days) episodes of continuous, but relatively mild ash emissions. Not all of them can be observed due to cloud cover, but show up from the accompanying volcanic tremor. This activity is probably mainly phreatic in nature, as the volcano’s currently unstable shallow hydrothermal system interacts with an underlying small magma body. Recent ash samples were found to contain about 10% juvenile material which originates from the new magma. Whether the amount of magma participating in the surface activity increases (towards a more magma-driven eruption) or decreases (ceases) in the near to medium future, i.e. how the eruption evolves, will depend on ho the volume of magma involved and may other factors (gas content, internal pressure etc) and cannot be predicted at the moment.

Poas (Costa Rica): The volcano remains highly restless, the hydrothermal system probably being disturbed by a shallow magma body. A sudden and quite violent phreatic explosion, result of overheated ground water flashing to steam, occurred last Tuesday, ejecting mud and water to 200 m above the crater lake.

Sabancaya (Peru): A pilot reported seeing a small ash plume from the volcano today. On satellite imagery, no ash is visible, but it’s plausible that a small eruption occurred. The volcano has been producing sporadic emissions from time to time during the past months. Buenos Aires VAAC keeps Aviation Color Code at yellow.

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