Supershear rupture in a M-w 6.7 aftershock of the 2013 Sea of Okhotsk earthquake

TitleSupershear rupture in a M-w 6.7 aftershock of the 2013 Sea of Okhotsk earthquake
Publication TypeJournal Article
Year of Publication2014
AuthorsZhan Z.W, Helmberger D.V, Kanamori H., Shearer PM
Date Published2014/07
Type of ArticleArticle
ISBN Number0036-8075
Accession NumberWOS:000339409900051
Keywords3-d; deep earthquakes; dynamic rupture; fault; mechanism; shear cracks; transition; wave-forms

Earthquake rupture speeds exceeding the shear-wave velocity have been reported for several shallow strike-slip events. Whether supershear rupture also can occur in deep earthquakes is unclear, because of their enigmatic faulting mechanism. Using empirical Green's functions in both regional and teleseismic waveforms, we observed supershear rupture during the 2013 moment magnitude (M-w) 6.7 deep earthquake beneath the Sea of Okhotsk, an aftershock of the large deep earthquake (M-w 8.3). The M-w 6.7 event ruptured downward along a steeply dipping fault plane at an average speed of 8 kilometers per second, suggesting efficient seismic energy generation. Comparing it to the highly dissipative 1994 M-w 8.3 Bolivia earthquake, the two events represent end members of deep earthquakes in terms of energy partitioning and imply that there is more than one rupture mechanism for deep earthquakes.

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