| Burma plate | |
|---|---|
 Depicted at center, shaded in light red | |
| Type | Minor |
| Approximate area | 1,100,000 km2[1] |
| Movement1 | north |
| Speed1 | 46 mm/year |
| Features | Andaman Sea |
| 1Relative to theAfrican plate | |
TheBurma plate is a minortectonic plate or microplate located inSoutheast Asia, sometimes considered a part of the largerEurasian plate. TheAndaman Islands,Nicobar Islands, and northwesternSumatra are located on the plate. Thisisland arc separates theAndaman Sea from the mainIndian Ocean to the west.
To its east lies theSunda plate, from which it is separated along atransform boundary, running in a rough north–south line through the Andaman Sea. This boundary between the Burma and Sunda plates is a marginalseafloor spreading centre, which has led to the opening up of the Andaman Sea (from a southerly direction) by "pushing out" the Andaman-Nicobar-Sumatraisland arc from mainland Asia, a process which began in earnest approximately 4 million years ago.
To the west is the much largerIndia plate, which is subducting beneath the western facet of the Burma plate. This extensivesubduction zone has formed theSunda Trench.
In models of the reconstructed tectonic history of the area, the generally northwards movement of theIndo-Australian plate resulted in its substantive collision with theEurasiancontinent, which began during theEoceneepoch, approximately 50–55 million years ago (Ma). This collision with Asia began theorogenic uplift which has formed theHimalaya mountains, as well as the fracturing of the Indo-Australian plate into the modern Indian plate,Australian plate, and possiblyCapricorn plate.[2]
As the India platedrifted northwards at a relatively rapid rate of an average 16 cm/yr, it also rotated in acounterclockwise direction. As a result of this movement and rotation, theconvergence along the plate's eastern boundary (the Burma–Andaman–Malay region) with Eurasia was at anoblique angle.[citation needed]
The transform forces along this subduction front started the clockwise bending of the Sunda arc; in the lateOligocene (ca. 32 Ma) further faulting developed and the Burma and Sunda microplates began to "break off" from the larger Eurasian plate.[citation needed]
After a further series of transform faulting, and the continuing subduction of the India plate beneath the Burma plate,backarc spreading saw the formation of themarginal basin and seafloor spreading centre which would become the Andaman Sea, a process well-underway by the mid-Pliocene (3–4 Ma).[citation needed]
On December 26, 2004, a large portion of the boundary between the Burma plate and theIndian plate slipped, causing the2004 Indian Ocean earthquake and tsunami.[3] Thismegathrust earthquake had an estimatedmoment magnitude of 9.1–9.3Mw.[4] Over 1,600 kilometres (990 mi) of the boundary underwentthrust faulting and shifted up to 5 metres (16 ft) vertically and 11 metres (36 ft) horizontally.[4] This rapid rise in the sea floor over such a short time (seven minutes[4]) generated a massivetsunami that killed approximately 229,800 people along the coast of the Indian Ocean.
