FALMOUTH, Mass., July 13 Many deep-ocean earthquakes may be smaller in magnitude than expected because of the fragmented structure of faults, Massachusetts researchers said.
Geophysicists from The Woods Hole Oceanographic Intuition said studies of gravity fields also suggest unrecognized volcanic activity may smooth rough edges of tectonic plates, WHOI said Friday in a release.
Examining data from 19 locations in the Atlantic, Pacific and Indian oceans, researchers led by graduate student Patricia Gregg found that "transform" faults are not developing or behaving as theories of plate tectonics say they should.
The researchers said many of the transform fault lines on the ocean floor are not as continuous as they first appear from low-resolution maps. Instead, it appears the fault lines are fragmented into smaller pieces, giving earthquakes less distance to travel along the surface.
Copyright 2007 by UPI
