A granular jamming model for low‐frequency earthquakes

摘要: A catalog of low frequency events (LFEs) beneath Vancouver Island is analyzed in the context of a granular flow model. The catalog contains origin‐times and magnitudes of 269,423 LFEs grouped within 130 families and recorded between 2003 and 2013. Each family represents a distinct location within the boundary between the subducting Juan de Fuca and overriding North American plates. The LFEs occurred during 10 episodic tremor and slip (ETS) events that recurred at ∼14‐month intervals and lasted for about a week. With one exception, each family was active in all 10 ETS episodes. Our analysis suggests that LFEs do not follow Gutenberg‐Richter statistics, but are normally distributed with respect to magnitude and, therefore, log‐normally distributed with respect to moment. The Kostrov strain associated with the moments in a given family is used to estimate its size as L = 350 ± 15 m. These observations …