| 25th October 2010 Indonesia on volcano eruption alert |
Residents urged to leave designated danger zone as seismologists warn of pressure building up beneath smoking crater. (Reuters) Hazards "Indonesian scientists have warned of a pressure build-up beneath Mount Merapi's lava dome, as authorities continue to evacuate tens of thousands of villagers to temporary shelters. An avalanche of rocks spilled down Merapi's slopes before dawn on Tuesday and gusts of ash rose 50 metres into the air as the mountain continued to rumble. Surono, a government volcanologist, said the greatest concern was pressure building behind a massive lava dome that has formed near the tip of the crater."  Geology and Tectonic Setting Merapi is a strato-volcano located in Central Java, Indonesia, about 30 km north of Yogyakarta city which has more than one million inhabitants. It is produced by subduction of the Australian plate under the Eurasian plate. The Indonesian archipelago resulted from complex and diverse tectonic processes (Simandjuntak & Barber, 1996, Wilson 1989, Hamilton, 1979).  Merapi is the most active volcano in Indonesia, erupting regularly since 1548. It is a typical andesitic Stratovolcano, historically producing effusive eruptions, which have become more explosive in recent history producing pyroclastic flows from collapsing lava domes. Merapi usually has poor gas content typically producing eruptions usually less than VEI 3 in size.   Aftermath of eruption http://www.bbc.co.uk/news/world-asia-pacific-11633213 The death toll following the eruption of Indonesia's Mount Merapi volcano has risen to 25, officials say, amid fears of fresh eruptions. Experts told the BBC that the ash levels had subsided a little, but that their readingssuggested there would be more volcanic activity soon. Thousands fled their homes on Tuesday as ash spewed out of the volcano, turning the landscape white. But many people refused to leave, and rescuers fear the death toll may rise. Current activity http://en.wikipedia.org/wiki/Mount_Merapi BBC Report http://www.bbc.co.uk/news/world-asia-pacific-11625154 Previous Events On 13th May 2006 , the Alert Level was raised to the highest level 4, and about 4,500 people living near the volcano were evacuated. On 15th May pyroclastic flows traveled up to 4 km west.On 8th June, the lava-dome growth rate at Merapi was an estimated 100,000 cubic meters per day, with an estimated volume of 4 million cubic meters. (http://www.volcanolive.com/merapi.html) In late November of 1994, collapse of a lava dome at Merapi generated pyroclastic flows and surges that travelled as far as 5 miles (7.5 km) from the summit. The flows and surges killed 43 people. The plume associated with the dome collapse rose 6 miles (10 km) above the volcano. Over 6,000 people were evacuated. The eruption also started fires. (http://volcano.oregonstate.edu/oldroot/volcanoes/merapi/merapi.html) Activity History http://indahnesia.com/volcano/gunung_merapi/activity_history.php Related Links@ http://indonesiandisaster.blogspot.com/2010/10/overview-of-merapi-volcano-central-java.html |
