Also see the archival list of Science's Compass: Enhanced Perspectives
GEOPHYSICS:
Enhanced: Slow But Not Quite Silent
Timothy I. Melbourne and Frank H. Webb
Regular earthquakes release large amounts of strain accumulated in Earth's crust within a very short time. Recently, a different type of earthquake has been reported from subduction zones around the world. Deep in Earth's crust, "slow" earthquakes may last weeks or months. In their Perspective, Melbourne and Webb explain that while slow, these earthquakes are not silent, as originally assumed. The authors highlight the report by Rogers and Dragert, who show that slow earthquakes in the Cascadia subduction zone, off the western coast of North America, are accompanied by a tremor that is absent when slow faulting is not occurring. The earthquakes are likely caused by fluid flow, a mechanism that may also apply to regular earthquakes.
T. I. Melbourne is in the Department of Geological Sciences, Central Washington University, Ellensburg, WA 98926, USA. E-mail: tim{at}geophysics.cwu.edu F. H. Webb is in the Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91125, USA.
