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Rupture complexity of the Mw 8.3 sea of okhotsk earthquake: Rapid triggering of complementary earthquakes?

Shengji Wei·Don Helmberger·Zhongwen Zhan·Robert Graves
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Abstract

We derive a finite slip model for the 2013 M w 8.3 Sea of Okhotsk Earthquake ( Z = 610 km) by inverting calibrated teleseismic P waveforms. The inversion shows that the earthquake ruptured on a 10° dipping rectangular fault zone (140 km × 50 km) and evolved into a sequence of four large sub-events (E1–E4) with an average rupture speed of 4.0 km/s. The rupture process can be divided into two main stages. The first propagated south, rupturing sub-events E1, E2, and E4. The second stage (E3) originated near E2 with a delay of 12 s and ruptured northward, filling the slip gap between E1 and E2. This kinematic process produces an overall slip pattern similar to that observed in shallow swarms, except it occurs over a compressed time span of about 30 s and without many aftershocks, suggesting that sub-event triggering for deep events is significantly more efficient than for shallow events.

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Shengji Wei, Don Helmberger, Zhongwen Zhan, Robert Graves. 2013-10-03. Rupture complexity of the Mw 8.3 sea of okhotsk earthquake: Rapid triggering of complementary earthquakes?. https://doi.org/10.1002/grl.50977

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