dimanche, mars 10, 2013
The strong seismic activity from Tolbachik obscures the seismicity of Bezymianny, but a thermal anomaly at the summit remains visible on satellite data and suggests that the lava dome continues to grow as well. [details]
vendredi, mars 01, 2013
A viscous lava flow continues to be active on the lava dome flank. Weak and moderate gas-steam activity accompany this process. [details]
Bezymianny volcanBezymianny ("unnamed") was considered extinct until it erupted violently in 1955-56, after a slumber of probably 1000 years. It is one of the most active volcanoes in Kamchatka. The eruption followed a massive flank failure (similar to Mt. St. Helens eruption in 1980) which removed a 0.5 sq km sector of the volcano.
Introduction:The present-day Bezymianny volcano, lying next to its massive sisters Kamen and Kliuchevskoi, is a young and relatively small volcano only about 4700 years old. It was formed on top of an older volcano built between about 11,000-7000 years ago. 3 periods of intensified activity have been recognized in the geologic history during the past 3000 years. The present-day activity started with the eruption in 1955-56 after a 1000 year interval of repose. At the beginning of the eruption, the summit and a large sector of its flank failed and resulted in a catastrophic landslide followed by a powerful blast. The event left a large horseshoe-shaped crater. Since then, the volcano has been one of Kamchatka's most active. A new lava dome has been growing inside the 1956 crater, frequently producing explosive activity and pyroclastic flows. As of 2011, the lava dome has already largely filled the 1956 crater.
Eruptions of Bezymianny since 1955
Lava dome growth, large explosions with ash columns up to 10-15 km high, and pyroclastic flows characterize the activity during this (ongoing) period. ...plus
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