The Burma plate is a minor

tectonic plate 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 ...

or microplate located in

Southeast Asia Southeast Asia is the geographical United Nations geoscheme for Asia#South-eastern Asia, southeastern region of Asia, consisting of the regions that are situated south of China, east of the Indian subcontinent, and northwest of the Mainland Au ...

, sometimes considered a part of the larger Eurasian plate. The

Andaman Islands The Andaman Islands () are an archipelago, made up of 200 islands, in the northeastern Indian Ocean about southwest off the coasts of Myanmar's Ayeyarwady Region. Together with the Nicobar Islands to their south, the Andamans serve as a mari ...

Nicobar Islands The Nicobar Islands are an archipelago, archipelagic island chain in the eastern Indian Ocean. They are located in Southeast Asia, northwest of Aceh on Sumatra, and separated from Thailand to the east by the Andaman Sea. Located southeast of t ...

, and northwestern

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. ...

are located on the plate. This

island arc Island arcs are long archipelago, chains of active volcanoes with intense earthquake, seismic activity found along convergent boundary, convergent plate tectonics, tectonic plate boundaries. Most island arcs originate on oceanic crust and have re ...

separates the

Andaman Sea The Andaman Sea (historically also known as the Burma Sea) is a marginal sea of the northeastern Indian Ocean bounded by the coastlines of Myanmar and Thailand along the Gulf of Martaban and the west side of the Malay Peninsula, and separated f ...

from the main

Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or approximately 20% of the water area of Earth#Surface, Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia (continent), ...

to the west. To its east lies the Sunda plate, from which it is separated along a transform boundary, running in a rough north–south line through the Andaman Sea. This boundary between the Burma and Sunda plates is a marginal seafloor spreading centre, which has led to the opening up of the Andaman Sea (from a southerly direction) by "pushing out" the Andaman-Nicobar-Sumatra

from mainland Asia, a process which began in earnest approximately 4 million years ago. To the west is the much larger India plate, which is subducting beneath the western facet of the Burma plate. This extensive

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 ...

has formed the Sunda Trench.

Tectonic history

In models of the reconstructed tectonic history of the area, the generally northwards movement of the Indo-Australian plate resulted in its substantive collision with the

Eurasia Eurasia ( , ) is a continental area on Earth, comprising all of Europe and Asia. According to some geographers, Physical geography, physiographically, Eurasia is a single supercontinent. The concept of Europe and Asia as distinct continents d ...

continent A continent is any of several large geographical regions. Continents are generally identified by convention (norm), convention rather than any strict criteria. A continent could be a single large landmass, a part of a very large landmass, as ...

, which began during the

Eocene The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...

epoch In chronology and periodization, an epoch or reference epoch is an instant in time chosen as the origin of a particular calendar era. The "epoch" serves as a reference point from which time is measured. The moment of epoch is usually decided b ...

, approximately 50–55 million years ago ( Ma). This collision with Asia began the orogenic uplift which has formed the

Himalaya The Himalayas, or Himalaya ( ), is a mountain range in Asia, separating the plains of the Indian subcontinent from the Tibetan Plateau. The range has some of the Earth's highest peaks, including the highest, Mount Everest. More than 100 pea ...

mountains, as well as the fracturing of the Indo-Australian plate into the modern Indian plate,

Australian plate The Australian plate is or was a major tectonic plate in the eastern and, largely, southern hemispheres. Originally a part of the ancient continent of Gondwana, Australia remained connected to India and Antarctica until approximately when Indi ...

, and possibly Capricorn plate. As the India plate drifted northwards at a relatively rapid rate of an average 16 cm/yr, it also rotated in a

counterclockwise Two-dimensional rotation can occur in two possible directions or senses of rotation. Clockwise motion (abbreviated CW) proceeds in the same direction as a clock's hands relative to the observer: from the top to the right, then down and then to ...

direction. As a result of this movement and rotation, the

convergence Convergence may refer to: Arts and media Literature *''Convergence'' (book series), edited by Ruth Nanda Anshen *Convergence (comics), "Convergence" (comics), two separate story lines published by DC Comics: **A four-part crossover storyline that ...

along the plate's eastern boundary (the Burma–Andaman–Malay region) with Eurasia was at an

oblique Oblique may refer to: * an alternative name for the character usually called a slash (punctuation) ( / ) *Oblique angle, in geometry * Oblique triangle, in geometry * Oblique lattice, in geometry * Oblique leaf base, a characteristic shape of the ...

angle. The transform forces along this subduction front started the clockwise bending of the Sunda arc; in the late

Oligocene The Oligocene ( ) is a geologic epoch (geology), epoch of the Paleogene Geologic time scale, Period that extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that defin ...

(ca. 32 Ma) further faulting developed and the Burma and Sunda microplates began to "break off" from the larger Eurasian plate. 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 the marginal basin and seafloor spreading centre which would become the Andaman Sea, a process well-underway by the mid-

Pliocene The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58Indian plate The Indian plate (or India plate) is or was a minor tectonic plate straddling the equator in the Eastern Hemisphere. Originally a part of the ancient continent of Gondwana, the Indian plate broke away from the other fragments of Gondwana an ...

slipped, causing the

2004 Indian Ocean earthquake and tsunami On 26 December 2004, at 07:58:53 local time ( UTC+7), a major earthquake with a magnitude of 9.2–9.3 struck with an epicentre off the west coast of Aceh in northern Sumatra, Indonesia. The undersea megathrust earthquake, known in the sci ...

. This

megathrust earthquake Megathrust earthquakes occur at convergent plate boundaries, where one tectonic plate is forced underneath another. The earthquakes are caused by slip along the thrust fault that forms the contact between the two plates. These interplate earthq ...

had an estimated moment magnitude of 9.1–9.3 . Over of the boundary underwent

thrust fault A thrust fault is a break in the Earth's crust, across which older rocks are pushed above younger rocks. Thrust geometry and nomenclature Reverse faults A thrust fault is a type of reverse fault that has a dip of 45 degrees or less. I ...

ing and shifted up to vertically and horizontally. This rapid rise in the sea floor over such a short time (seven minutes) generated a massive

tsunami A tsunami ( ; from , ) is a series of waves in a water body caused by the displacement of a large volume of water, generally in an ocean or a large lake. Earthquakes, volcanic eruptions and underwater explosions (including detonations, ...

that killed approximately 229,800 people along the coast of the Indian Ocean.

Tectonic history

References

Further reading