Transcript Mount Merapi “Mountain of Fire” Java, Indonesia Matt Treveloni & Ryder Arsenault Department of Geology @ Colby College.

Mount Merapi
“Mountain of Fire”
Java, Indonesia
Matt Treveloni & Ryder Arsenault
Department of Geology @ Colby College
Location
Pacific Ring of Fire
30 km North of
Yogyakarta, Indonesia
Destructive plate
margin (IndoAustralian Plate &
Eurasian Plate)
Form & Dimensions
Stratovolcano
Elevation: 2,930 m,
1,356 m above ground
Summit is higher on
the North, lahars and
pyroclastic flows run
down the South side
Years of eruptions
created distinct trench
Eruptions
Fault line: Sunda-Banda Arc
Subduction of Indo-Australian Plate
under the Eurasian Plate (twice as
thick)
Erupts: Hot gas, ashes, volcanic
bombs (pyroclastic flows, lahars)
Mt. Merapi erupts every
4-5 years with bigger
eruptions every decade
(2010), but smoke is
seen emerging 300 days
a year!
Rocks & Deposits
Most of the lavas from
Merapi are high
potassium basaltic
andesites.
The lava from Mt.
Merapi is mainly
porphyritic.
Plagioclase and
clinopyroxene are
the most common
phenocrysts.
Silica content ranges from 52 to 57%.
Phenocrysts can occupy up to 60% of
the total rock volume in Mt. Merapi’s
lava.
2010 Eruption
Effects of the 2010
Eruption
Fun Facts
The safe zone for the
2010 eruption was 20
km from the volcano.
Over 4 million people
live within 30 km.
Dome Collapse
Over 300,000
people were forced
to evacuate their
homes.
Crop Destruction
Why is Mt. Merapi So
Dangerous?
● Mt. Merapi has produced more pyroclastic
flows than any other volcano in the world
● Only 30 km away from Yogyakarta (population
~400K) which lies directly in flow path
● Indonesia’s intense rainfall causes massive
lahars
Culture & Other Info
● Considered sacred by local people, they believe
that a supernatural kingdom exists at the
summit and a priest makes an offering once a
year
● Ash leads to fertile soil
● Conservation area (unsafe to live) and illegal to
climb to summit
● Tourism lies in museums
● No geothermal energy or hydrothermal activity
Monitoring
● Seismology
○ There are 8 seismograph stations in the network.
● Volcanomagnetism
○ Since 1977 they monitor the magnetism beneath the Earth’s
surface.
● Deformation
○ Three GPS signals measure to make sure the distance and
angles between all three remain the same.
○ In 1990 they introduced tilt monitors to measure deformation.
● Geochemistry
○ There are two solfatara fields used for measuring the volcanic
gases.
● Lahar Detection
○ Lahars are usually triggered by heavy rainfall.
○ An acoustic sensor measures the noise given off by a lahar in
order to detect when one begins moving.
References
Marliyani, G.I., 2010: An Overview of Merapi Volcano, Central Java, Indonesia, at
http://mountmerapi.net/mount-merapi/ (accessed 22 January, 2015)
Leontiou, A., 2010: FAQ: A Look Inside Mount Merapi, at http://www.livescience.com/11081faq-mount-merapi.html (accessed 24 January, 2015)
Lavigne, F. & Thouret, J.C., 2003: Sediment transportation and deposition by rain-triggered
lahars at Merapi Volcano, Central Java, Indonesia, at
http://www.sciencedirect.com/science/article/pii/S0169555X02001605 (accessed 23
January, 2015)
Seach, J., 2012: Merapi Volcano, at http://www.volcanolive.com/merapi.html (accessed 25
January, 2015)
Simkin, T. & Siebert, L., 1994: Volcanoes of the World, at
http://volcano.oregonstate.edu/oldroot/volcanoes/merapi/merapi.html (accessed 25
January, 2015
References
Boston.com 2010: Mount Merapi’s eruptions at
http://www.boston.com/bigpicture/2010/11/mount_merapis_eruptions.html
(Accessed 25 January, 2015)
Geotalk, 2012. Mt. Merapi Eruption at http://www.geotalk.info/#!mt-merapi/c21bv
(Accessed 25 January, 2015)
Gertisser, R. 2003: Temporal Variations in magma composition at Merapi Volcano
at http://www.sciencedirect.com/science/article/pii/S0377027303000258
(Accessed 25 January, 2015)
Smithsonian Institution, 2013: Global Volcanism Program at
http://volcano.si.edu/volcano.cfm?vn=263250 (Accessed 25 January, 2015)
Youtube 2010: Merapi Eruption: Travel chaos as volcano spews massive clouds of
ash at https://www.youtube.com/watch?v=nEBTfQ79Z7A (Accessed 25
January, 2015)