The Great Sumatran fault, also known as Semangko fault, is a large
strike-slip fault
In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tectonic ...
running the entire length of the island of
Sumatra
Sumatra () is one of the Sunda Islands of western Indonesia. It is the largest island that is fully within Indonesian territory, as well as the list of islands by area, sixth-largest island in the world at 482,286.55 km2 (182,812 mi. ...
. This
Indonesia
Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania, between the Indian Ocean, Indian and Pacific Ocean, Pacific oceans. Comprising over List of islands of Indonesia, 17,000 islands, including Sumatra, ...
n island is located in a highly
seismic
Seismology (; from Ancient Greek σεισμός (''seismós'') meaning "earthquake" and -λογία (''-logía'') meaning "study of") is the scientific study of earthquakes (or generally, quakes) and the generation and propagation of elastic ...
area of the world, including a
subduction zone
Subduction is a geological process in which the oceanic lithosphere and some continental lithosphere is recycled into the Earth's mantle at the convergent boundaries between tectonic plates. Where one tectonic plate converges with a second p ...
off the west coast of the island.
The Great Sumatran fault zone accommodates most of the strike-slip motion associated with the oblique convergence between the
Indo-Australian plate and
Eurasian plate The fault ends in the north near the city of
Banda Aceh
Banda Aceh (; , Jawi script, Jawi: ) is the capital and largest city in the province of Aceh, Indonesia. It is located on the island of Sumatra and has an elevation of 35 metres. The city covers an area of and had a population of 223,446 peopl ...
, which was devastated in the
2004 Indian Ocean earthquake
On 26 December 2004, at 07:58:53 local time (UTC+07:00, UTC+7), a major earthquake with a magnitude of 9.2–9.3 struck with an epicenter, epicentre off the west coast of Aceh in northern Sumatra, Indonesia. The Submarine earthquake, undersea ...
.
Geologic significance
The Great Sumatran fault is part of the system where
strain partitioning was first described in
plate tectonics
Plate tectonics (, ) is the scientific theory that the Earth's lithosphere comprises a number of large tectonic plates, which have been slowly moving since 3–4 billion years ago. The model builds on the concept of , an idea developed durin ...
. The convergence between the
Indo-Australian plate and the
Sunda plate is not perpendicular to the plate boundary in this region. Instead, the two plates move at an oblique angle. Most of the convergent strain is accommodated by thrust motion at the plate boundary "megathrust" fault that defines the
Sunda Trench. But the oblique motion (the part of the plate motion parallel to the plate boundary) is accommodated by the Great Sumatran fault, which runs along the volcanic
Sunda Arc.
The area between the main plate boundary thrust fault and the Great Sumatran fault forms a "sliver plate" that includes the entire offshore forearc, forearc islands, and the portion of Sumatra west of the Great Sumatran fault. This sliver plate is not a single rigid bloc, and the details of its internal deformation are under active investigation.
Earthquakes
Listed from northwest to southeast:
* April 2, 1964:
Mw 7.0 event near the northern tip of Sumatra and the city Banda Aceh.
* September 19, 1936:
Mw 7.2 event (3.685°N 97.535°E)
*
March 2007 Sumatra earthquakes: Doublet earthquakes of moment magnitude 6.4 and 6.3 two hours apart northeast of
Lake Singkarak.
*
2022 Sumatra earthquake: A magnitude 6.2 earthquake damaged dozens of homes, offices and a school.
Six killed and 32 injured. Felt in Malaysia and Singapore.
*
1926 Padang Panjang earthquakes: Doublet earthquake measuring 6.7 and 6.4. At least 411 people killed.
*
1943 Alahan Panjang earthquakes: Doublet earthquakes of moment magnitude 7.2 and 7.5 occurred within 7 hours of each other on June 8 and 9 southeast of
Lake Singkarak.
*
1995 Kerinci earthquake: Moment magnitude 6.8 earthquake, killed at least 84 people and caused 1,868 injuries.
*
1994 Liwa earthquake: 7.0
Mw event caused 207 deaths near the southern tip of Sumatra.
*
1933 Sumatra earthquake:
Mw 7.6 event (5.226°S 104.596°E) southern of Sumatra.
More than 76 people killed and extensive damage. Two towns destroyed.
See also
*
Ring of Fire
The Ring of Fire (also known as the Pacific Ring of Fire, the Rim of Fire, the Girdle of Fire or the Circum-Pacific belt) is a tectonic belt of volcanoes and earthquakes.
It is about long and up to about wide, and surrounds most of the Pa ...
References
Further reading
*
External links
Great Sumatran Fault
Seismic faults of Southeast Asia
Strike-slip faults
Seismic faults of Indonesia
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