Megathrust earthquakes

Megathrust earthquakes occur at zones at destructive, where one  is forced underneath another, caused by slip along the  that forms the contact between them. These s are the planet's most powerful, with (Mw) that can exceed 9.0. Since 1900, all s of magnitude 9.0 or greater have been megathrust earthquakes. No other type of known terrestrial source of tectonic activity has produced earthquakes of this scale.

Terminology
During the rupture, one side of the fault is pushed upwards relative to the other, and it is this type of movement that is known as. They are a type of. A thrust fault is a reverse fault with a dip of 45° or less. have significant components of different slip styles. The term megathrust does not have a widely accepted rigorous definition, but is used to refer to an extremely large thrust fault, typically formed at the plate interface along a subduction zone such as the.

Areas
Megathrust earthquakes are almost exclusive to tectonic subduction zones and are often associated with the and s. These subduction zones are not only responsible for megathrust earthquakes, but are also largely responsible for the  activity associated with the.

Since the earthquakes associated with these subduction zones deform the, they often generate a significant series of waves. Subduction zone earthquakes are also known to produce intense shaking and ground movements for significant periods of time that can last for up to 5-6 minutes.

In the region, the  is located where the  is subducting under the  and extends 5,500 km (3300 mi) off the coasts of, ,  and  before terminating off the northwestern coast of. This subduction zone was responsible for the.

In Japan, the Nankai megathrust under the is responsible for  and associated tsunamis.

In the United States and Canada, the is subducting under the  creating the  which stretches from Middle Vancouver, British Columbia to Northern California. This subduction zone was responsible for the.

A study reported in 2016 found that the largest megathrust quakes are associated with downgoing slabs with the shallowest dip, so-called.

Examples
Examples of megathrust earthquakes are listed in the following table.