Megathrust earthquake

[4][5] However, the term is also occasionally applied to large thrust faults in continental collision zones, such as the Himalayan megathrust.

Thrust faults are characteristic of areas where the Earth's crust is being compressed by tectonic forces.

A megathrust earthquake takes place when the fault ruptures, allowing the plates to abruptly move past each other to release the accumulated strain energy.

[5] These subduction zones are also largely responsible for the volcanic activity associated with the Pacific Ring of Fire.

[13] Subduction zone earthquakes are also known to produce intense shaking and ground movements that can last for up to 3–5 minutes.

[14] In the Indian Ocean region, the Sunda megathrust is located where the Indo-Australian plate subducts under the Eurasian plate along a 5,500 kilometres (3,400 mi) fault off the coasts of Myanmar, Sumatra, Java and Bali, terminating off the northwestern coast of Australia.

Therefore, the largest possible earthquake in the region is a magnitude 9.7, assuming a single rupture of the whole Himalayan arc and assuming standard scaling law, which implies an average slip of 50 m.[24] A megathrust earthquake could occur in the Lesser Antilles subduction zone, with a maximum magnitude of 9.3, or potentially even 10.3 through recent evaluations, a value not considered impossible.

The largest megathrust earthquakes occur in subduction zones with thick sediments, which may allow a fault rupture to propagate for great distances unimpeded.