Merapi is a stratovolcano with an active summit lava dome.
It is located ~30 km immediately north of Yogyakarta, a city with a population
of 500,000. Merapi has the unfortunate distinction of producing more nuee
ardentes than any other volcano on Earth. The nuee ardentes result from
collapse of the lava dome at the summit. Of the 67 historic eruptions 32 have
had nuee ardentes associated with them. Eleven of these eruptions resulted in
fatalities. Merapi is closely monitored by the Volcanological Survey of
Indonesia. Shortly before this photograph was taken Merapi was generating up to
40 nuee ardentes per day. Photograph by Robert Koyanagi, U.S. Geological
Survey, July 28, 1979.
Rockfall from
the collapse of a lava dome. Photo by Jack Lockwood, U.S. Geological
Survey, September 8, 1982.
Lava dome at
the summit of Merapi. During 1982, the lava dome was growing about
80,000-100,000 cubic meters per month. The dome collapsed in late November,
creating nuee ardentes. Photo by Jack Lockwood, U.S. Geological Survey,
October 17, 1982.
Pyroclastic flow deposit on Merapi. Photo by Jack
Lockwood, U.S. Geological Survey, November 2, 1982.
Kadong school is in the lower left of this photo.
Barriers (just left of the stream valley) have protected the school
fromlahars. In 1979, heavy rainfall mobilized old lahar deposits to create
landslides that travelled as far as 12 miles (20 km) downslope. Eighty people
were killed. Photo by Jack Lockwood, U.S. Geological Survey, September 26,
1982.
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.
Sumber : http://volcano.oregonstate.edu/merapi
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