Indonesia Volcano Eruption

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."  (Merapi Lava Dome 1982)  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. Regional Map 26th October 2010 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 readings suggested 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

The fissure vent eruption on Eyjafjallajokull in Iceland

A volcano in southern Iceland dormant for nearly 200 years erupted back into life earlier today, creating a fissure eruption 1km long within glacier fields of southern Iceland. The eruption as been described as gentle, pictures and reports indicate a fissure eruption; lava flows and ashfall have been seen.
There were initial concerns that it could trigger flooding throught the melting of the overlying glacier however , University of Iceland geologist Tumi Gudumundsson is quoted by ABC News as saying that the eruption is located beneath an ice-free portion of the volcano, lessening the chances of a glacial flood being caused by melted ice.
There is however concern that the initial eruption could trigger more aggressive eruption from the  nearby Katla Volcano.
Icelanders agree. "This could trigger Katla, which is a vicious volcano that could cause both local and global damage," Pall Einarsson, from the University of Iceland, said.

Geological setting:-
The ice-cap of the glacier covers an active volcano (1666m in height) which has erupted rather frequently since the ice-age. The last eruption was in 1821-23, causing a fatal glacier run. The crater of the volcano has a diameter of 3-4 km, the glacier covering an extension of about 100 km².

Larger threat:-

"The eruption at Eldgja in ~935 AD lasted 3-8 years and produced 19.6 cubic km of lava, making it the largest basaltic flood lava eruption in historic time. The fissure was about 30 km long. An estimated 219 Mt of SO2 was released to the atmosphere during the eruption which may have produced as much as ~450 Mt of H2SO4 aerosol."


Video of the eruption



Wednesday 13th April

REYKJAVIK - Up to 800 people were evacuated in Iceland early Wednesday due to a volcano eruption under the Eyjafjallajokull glacier in the south of the island, police and geophysicists said.

"Between 700 and 800 people were evacuated from their homes," police spokesman Baldur Sigurdsson told AFP, pointing out that "there were a lot of earthquakes in the area."

"There is an eruption going on in the southwestern part of Eyjafjallajokull's top crater. Smoke coming out of the top crater is towering more than 20,000 feet (6,000 metres) in the air," said geophysicist Gunnar Gunnarsson of Iceland's Meteo Institute.

Image http://news.bbc.co.uk/1/hi/sci/tech/8621992.stm

New Scientist Article

http://www.newscientist.com/article/dn18786-get-ready-for-decades-of-icelandic-fireworks.html

"Volcanologists say the fireworks exploding from the Eyjafjallajökull volcano on Iceland, which is responsible for the ash cloud that is grounding all commercial flights across northern Europe, may become a familiar sight. Increased rumblings under Iceland over the past decade suggest that the area is entering a more active phase,

with more eruptions and the potential for some very large bangs."

"Judging by recent volcanic and earthquake activity, Thordarson and his colleagues believe that Iceland is entering its next active phase and estimate it will last for 60 years or so, peaking between 2030 and 2040."

Journal reference: Geology, vol 26, p 943
Impact on Human Activity

"In 1982, British Airways and Singapore Airways jumbo jets lost all their engines when they flew into an ash cloud over Indonesia."

Reports said that the ash sandblasted the windscreen and clogged the engines, which only restarted when enough of the molten ash solidified and broke off.

"This dust really is nasty stuff," he told BBC News. "It's extremely fine and if it gets into a jet engine, it blocks up all of the ventilation holes that bleed in cooling air.

"Jet engines operate at about 2,000C, and the metals can't take that. The engine will just shut down."

Links and additional resources

BBC News http://news.bbc.co.uk/1/hi/world/europe/8622978.stm

"We can actually smell sulphur in the air here now from the volcano cloud "Tim Farish, Oslo.

http://news.bbc.co.uk/1/hi/uk/8623806.stm?ls  Iceland Volcano ground airflights for second day.

Iceland Why a cloud of ash has grounded flights
http://news.bbc.co.uk/1/hi/sci/tech/8621992.stm

EUMETSAT Animation of Ash Cloud http://oiswww.eumetsat.org/IPPS/html/MSG/RGB/ASH/ICELAND/