Plate data: Bird (2003), PB2002, converted by Hugo Ahlenius, Nordpil (ODC-By 1.0). Land: Natural Earth (India POV).
The Sunda Plate carries most of Southeast Asia. Bird (2003), following Rangin and others (1999), describes it as including the South China Sea, the Malay Peninsula, most of Sumatra, Java, Borneo and the shallow seas between them. Early 14-plate models of the Earth counted this region as part of the Eurasian Plate.
Bird explains why PB2002 splits it off: the collision of India with Eurasia moved south China and Southeast Asia a long way relative to the European and Siberian core of Eurasia. The plate interior has a very low rate of shallow earthquakes, a sign that it deforms little. GPS campaigns in 1994 and 1996 give it velocities of 17 to 28 mm per year relative to Eurasia, toward the northeast to east-northeast.
Its edges are busy. Subduction zones separate it from the Australian and Philippine Sea Plates, and most of its boundary on this map is convergent.1 Its northern edge is different: Bird drew it along the northern extent of the aseismic region and smooth topography of Southeast Asia, and notes that the western part borders deforming parts of Eurasia, not stable Eurasia.
This is one of the most volcanic regions on Earth. USGS describes the 1883 eruption of Krakatau, in the Sunda Straits between Sumatra and Java, whose tsunamis washed away 165 coastal villages and killed 36,000 people, and calls the 1815 eruption of Tambora in Indonesia the most powerful eruption in recorded history. In PB2002 both volcanoes sit on the Sunda Plate.2
USGS places Mount Pinatubo, on Luzon in the Philippines, on the western edge of the Philippine Plate. On 15 June 1991 it spewed ash 40 km into the air (USGS). Bird treats the Philippine Islands as an orogen where the plate model is not expected to be accurate, and on this map Pinatubo falls on the Sunda Plate.2
Sunda Plate in numbers
Measured from its PB2002 outline, the Sunda Plate covers about 8.9 million km², or 1.7% of the
Earth's surface. That makes it number 11 by area of the 52 plates in the model.
It spans from 12°S to 22°N and from 94°E to 129°E.
Its edge is about 14,029 km long, mostly convergent:
11.4%divergentDivergent boundary. Plates pull away from each other and new crust forms between them. Source (1,596 km)
, 62.3%convergentConvergent boundary. Plates move toward each other and crust is destroyed as one plate dives under another. Source (8,740 km)
and 26.3%transformTransform boundary. Plates slide horizontally past each other. Crust is neither made nor destroyed. Source (3,693 km)
.
Countries whose main landmass sits on this plate: Brunei, Cambodia, Indonesia, Laos, Malaysia, Philippines, Thailand and Vietnam. Countries that straddle a boundary
are listed under the plate that holds the center of their largest landmass.
Along its boundaries it moves a mean 5.2 cm/yr relative to its neighbors, fastest against the Philippine Sea Plate. Bird (2003)
Neighboring plates Neighbors. Plates that share a boundary with this plate. Most plate movement happens along these narrow zones between plates. Source
The Sunda Plate shares a boundary with 9 plates in PB2002, longest shared edge first.
The longest, about 3,294 km, is with the Australian Plate; the shortest, about 413 km, is with the Birds Head Plate.
