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| Great Sumatran fault | |
|---|---|
| Semangko Fault | |
 | |
| Location | Sumatra |
| Country | Indonesia |
| Characteristics | |
| Length | ~1650-1900km |
| Tectonics | |
| Plate | Australian plate, Eurasian plate |
| Earthquakes | 24 June 1933, 19 Sept 1936, 1943 Alahan Panjang earthquake, 2 April 1964, 1994 Liwa earthquake, March 2007 Sumatra earthquakes |
| Type | strike-slip fault |
TheGreat Sumatran fault, also known asSemangko fault, is a largestrike-slip fault running the entire length of the island ofSumatra. ThisIndonesian island is located in a highlyseismic area of the world, including asubduction zone 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 theIndo-Australian plate andEurasian plate[1] The fault ends in the north near the city ofBanda Aceh, which was devastated in the2004 Indian Ocean earthquake.
The Great Sumatran fault is part of the system wherestrain partitioning was first described inplate tectonics.[2] The convergence between theIndo-Australian plate and theSunda 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 theSunda 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 volcanicSunda 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.[3]
Listed from northwest to southeast:
