Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA 92093-0225, USA. Seismological Laboratory, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125, USA.
Seismological Laboratory, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125, USA.
Science. 2014 Jul 11;345(6193):204-7. doi: 10.1126/science.1252717.
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.
已经有报道称，一些浅层走滑型地震的破裂速度超过了剪切波速度。由于其神秘的断层机制，深部地震是否也会发生超剪切破裂尚不清楚。我们利用区域和远震波形中的经验格林函数，观测到了鄂霍次克海 2013 年矩震级（M(w)）6.7 深震的超剪切破裂，该地震是一次大型深震（M(w) 8.3）的余震。M(w) 6.7 事件以平均 8 公里/秒的速度沿陡倾的断层面向下破裂，表明地震能量的有效产生。将其与高耗散的 1994 年 M(w) 8.3 年玻利维亚地震相比，这两个事件代表了深部地震在能量分配方面的两个极端，这意味着深部地震可能有多种破裂机制。
