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Seismic evidence for an earthquake nucleation phase

January 1, 1995

Near-source observations show that earthquakes initiate with a distinctive seismic nucleation phase that is characterized by a low rate of moment release relative to the rest of the event. This phase was observed for the 30 earthquakes having moment magnitudes 2.6 to 8.1, and the size and duration of this phase scale with the eventual size of the earthquake. During the nucleation phase, moment release was irregular and appears to have been confined to a limited region of the fault. It was characteristically followed by quadratic growth in the moment rate as rupture began to propagate away from the nucleation zone. These observations suggest that the nucleation process exerts a strong influence on the size of the eventual earthquake.

Publication Year 1995
Title Seismic evidence for an earthquake nucleation phase
Authors W.L. Ellsworth, G. C. Beroza
Publication Type Article
Publication Subtype Journal Article
Series Title Science
Index ID 70018970
Record Source USGS Publications Warehouse