Monday, 7 March 2016

Volcanos

Roundup of Global Volcanic Activity

Shiveluch (Kamchatka): The lava dome continues to be very active, generating frequent rockfalls and small glowing avalanches on the SW side as well as, more rarely, on the SE side. A larger event might have taken place after dark, as Tokyo VAAC reported an ash plume to 18,000 ft (5.4 km) altitude this morning 08:20 UTC (17:20 local time in Kamchatka).

Chirpoi (Kurile Islands, Russia): A new eruption might have taken place at the volcano this afternoon. Based on satellite imagery, Tokyo VAAC reported an ash plume to estimated 20,000 ft (6 km) altitude that drifted east. Whether or not an eruption took place still needs to be confirmed.

Copahue (Chile/Argentina): The activity at the volcano, near-constant degassing with sometimes ash emissions, has decreased over the past weeks. Ash venting has become less frequent and intense, and the glow from E Agrio crater that had been visible at the crater disappeared. According to the Chilean scientists from SERNAGEOMIN who monitor the volcano, the current activity of the volcano is being caused by the interaction of a small volume of new magma under its highly active shallow hydrothermal system - none or little of this magma reaches the surface itself, but the heat transfer into the circulating fluids causes fragmentation by small explosions and the emission of gasses and particles (ash). This activity reflects in a continuous tremor signal of moderate intensity.

Scientists concluded that the new magma volume has been too small to greatly affect the internal balance in the hydrothermal system. Other geophysical parameters such as rate of degassing and deformation are mostly within normal levels of the volcano. It is therefore expected that the current activity continues in the coming weeks to months at fluctuating rates. This includes possible short-lived phases of more pronounced sporadic phreatic to strombolian explosions.

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