Merapi volcano (Central Java): increased seismic activity could indicate the start of a new lava dome growth
Friday Feb 17, 2012 11:05 AM | BY: T
Seismic activity has increased beneath Mount Merapi volcano in Central Java, Indonesia, in the last few days. The increase in so-called multiphase earthquakes is thought to indicate the beginning of the formation of a new lava dome.
A volcanologist from the Selo observation post on the north side of the volcano is quoted "there is movement in the magma chamber in the form of a new lava dome formation. But we do not know the emission point because from Selo it is not visible". It is planned to check the situation at the summit in the near future. "The status of Merapi still active normal."
Starting around 11 February, Mount Merapi showed increased seismic activity, especially in multi-phase (MP) earthquakes, which are believed to correspond to movements in the magma chamber and conduits. During the week of 29 January and 4 Feb 29, 18 such quakes were recorded, but that figure rose sharply during the following week, when about 100 were recorded. The peak occurred on 12 February, when 63 MP as well as 6 shallow volcanic earthquakes were recorded.
On 13 February earthquake activity decreased to 34 MP quakes, 3 avalanche, and 9 shallow volcanic and tectonic quakes. On 14 February, there were 25 MP and 14 shallow volcanic quakes.
The Head of the Regional Disaster Management Agency (BPBD) Mr Boyolali Hasanudin confirmed that the increased activity of Mount Merapi is a normal phenomenon frequently seen at the volcano, and still within the range of normal fluctuations. The official alert level remains at 1 out of 4 (normal activity).
People living on the slopes of Mount Merapi, particularly those living higher up the slopes and near the major drainage valley are encouraged to remain vigilant. A major hazard for these areas are floods and mud flows, particularly now in the rainy season.
Links / Sources:
Monday, Mar 21, 2011
A powerful lahar (mud flow) occurred on 21 March on the SW flank of Merapi volcano. A lahar traveled through the village of Sleman, approximately 20 km SW of Merapi, burying 21 homes in addition to vehicles and livestock. At least 200 residents were evacuated. [more]
Sunday, Nov 14, 2010
A small pyroclastic flow occured at Merapi yesterday, reaching 1.8 km from the summit. Today, the explosive activity from the vents at the summit seems to have decreased further. The ash plume rises to about 1 km above the crater and appears to be much smaller in volume than yesterday. Yogyakarta airport is scheduled to reopen on 16 Nov, if the trend of decreasing activity continues. [more]
Saturday, Nov 13, 2010
After the powerful explosions and devastating pyroclastic flows last weekend, and a minor pyroclastic flow on 11 Nov morning, Merapi's activity has sharply decreased. ... [more]
Saturday, Nov 06, 2010
Strong eruptions continue at Merapi volcano, Indonesia. Violent explosions are audible tens of kilometers away from the summit. Magma is still rising inside the volcano and even more powerful explosions could occur. Ash from the explosions and from pyroclastic flows is forming a large plume reaching 10-20 km altitude and extending now over 300 km to the west. The ash threatens to reach the airspace of Jakarta airport soon, which promted Singapore Airlines, Lufthansa, Emirates and other airlines to suspend long-haul flights to Jakarta for the time being. ... [more]
Friday, Nov 05, 2010
The eruption of Merapi, now already the worst since at least 1872, is still increasing, and news are hard to keep up with: extremely large and dangerous pyroclastic flows occured yesterday and today, reaching up to 13-18 km distance. Tragically, more than 77 more people have been killed, bringing the total death toll to over 100 so far. ... [more]