M7.4 - MARTINIQUE REGION, WINDWARD ISLANDS

Tectonic Summary

The Martinique earthquake 29 November 2007 occurred in the inclined seismic zone that dips to the west beneath the Lesser Antilles islands arc. In the region of Martinique, the South America plate moves to the west-northwest with respect to the Caribbean plate with a velocity of about 2 cm/yr. This relative motion is accommodated largely by the South America plate thrusting beneath the Caribbean plate. The earthquake occurred within the subducted South America plate, in response to stresses generated by plate's slow distortion, rather on the thrust fault that constitutes the interface the between the Caribbean and South America plates. The subducted South American plate is seismically active to depths of almost 200 km beneath the Lesser Antilles island arc near Martinique.

Earthquakes, such as this one, that have focal-depths between 70 and 300 km are commonly termed "intermediate-depth" earthquakes. Intermediate-depth earthquakes typically cause less damage on the ground surface above their foci than is the case with similar magnitude shallow-focus earthquakes, but large intermediate-depth earthquakes may be damaging nonetheless and may be felt at great distance from their epicenters

Earthquake Information for Caribbean