Tectonic Plates of the World

	Plate boundaries are approximate. Subduction plate boundaries are arbitrarily mapped. Subduction of plates occurs in a wide zone of plate contact, instead of a definite boundary. This zone is defined by a zone of frequent earthquakes. Most large earthquakes are generated by subduction, including megathrust earthquakes that exceed the magnitude of 8.0. The Sumatra Section of the subduction zone has been very active since the giant tsunami-generating megathrust earthquake of December 26, 2004, which reached 9.0 on the Richter Scale.