Sinabung volcano (Sumatra): eruption news and activity updates
Sinabung volcano (Sumatra) - increasing pyroclastic flows from lava dome
Sunday Jan 05, 2014 07:17 AM | BY: T
Pyroclastic flow from Sinabung yesterday
The current eruption, characterized by the growing lava dome producing numerous explosions and pyroclastic flows, continues at increasing levels.
Seismic activity of Sinabung during the past weeks (VSI, annotated by Blog Culture Volcan)
During yesterday, several (at least 5) pyroclastic flows (hot block and ash avalanches triggered by partial collapse of the unstable dome) traveled down on the southeastern side and reached lengths of up to 4 km, with associated ash plumes rising more than 4 km height to altitudes of 24,000 (7.3 km). The following video shows some of the flows through the VSI webcam:
As a response, authorities increased the exclusion zone from 5 to 6 km radius, with the implication that 2 more villages (Pintu Besi and Jeraya) are now being evacuated. The emergency status was extended to at least until 18 January, meaning that the currently over 20,000 displaced people will not be able to return to their homes any time soon. Large areas around the volcano have now been covered by ash and most vegetation including many important crop plantations in these are destroyed.
VSI published a new report about the activity since 27 December, which is partially summarized here (following the summary originally posted by Blog Culture Volcan):
- Hybrid earthquakes, resulting from the both rock fracturing and moving magma, i.e. directly associated with the currently growing lava dome rose to an average of 471 events per day.
- A large increase in signals caused by avalanches and pyroclastic flows was seen since 30 Dec, which corresponds to the time the lava from the dome could overspill its crater and start to form rock falls. Currently, VSI measures about 100 events per day.
Since the lava dome started to produce rockfalls (or pyroclastic flows), in other words, loose some mass as well, part of the (upper) volcanic edifice started to show deflation. This would be explained by the decrease in pressure induced by the mass loss at the dome. As Culture Volcan mentioned, this is in a way a good effect because it decreases (but not eliminates) the risk of a larger explosion that can occur if too much pressurized viscous magma is trapped in the conduit or the dome.
Links / Sources:
Links / Sources:
- Sinabung: l'activité ne se calme pas (Blog Culture Volcan)
Friday, Jan 03, 2014
More explosions (and probably pyroclastic flows) occurred this morning. An ash plume rose to estimated 24,000 ft (7.3 km) altitude. [more]
Thursday, Jan 02, 2014
The volcano's eruption continues with increasing and more and more frequent (every 15 minutes) explosions and pyroclastic flows from the growing lava dome. Ash plumes have been reaching 20,000 ft (6 km) altitude, run-out lengths of the pyroclastic flows approx. 2-3 km. ... [more]
Tuesday, Dec 31, 2013
More and increasingly larger (and hence more dangerous) pyroclastic flows are being formed by the growing lava dome of the volcano. These "flows" are hot turbulent avalanches of hot blocks and ash in suspension with hot gas and air, that can travel down at great speed the slopes of the mountain, typically following the paths of valleys. ... [more]
Monday, Dec 30, 2013
The growing lava dome has started to produce (extremely dangerous) pyroclastic flows, as parts of the unstable mass of the viscous lava have now overtopped the crater the dome had been growing inside. ... [more]
Saturday, Dec 28, 2013
VSI confirmed that a new lava dome (a mass of viscous magma accumulating at the vent) has made its appearance on the northern crater of the volcano. It had a height of 56 meters and diameter of 105 meters on 26 Dec. Its volume was estimated to about 1 million cu meters, and the growth rate at 3.5 m3/second. ... [more]