Thursday, November 29, 2007

USGS report on quake

From the USGS website:

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...

Earthquakes, such as this one, that have focal-depths between 70 and 300 km are commonly termed "intermediate-depth" earthquakes...[and]... 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 felt at great distance from their epicenters



So, now we know!

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