![]() The answer seems to be that the M 7.1 rupture cast a ‘stress shadow’ over the cross fault, inhibiting failure by several bars, and so shutting aftershocks off. (The calculation is for ‘optimally-oriented’ strike-slip faults with friction of 0.4 at 10 km depth.) Maps of seismicity and calculated Coulomb stress change for the Ridgecrest sequence. But when the M 7.1 struck 34 hours later, seismicity along the cross fault abruptly stopped (middle panel below). Two perpendicular faults ruptured in the M 6.4 earthquake on July 4 (left panel below), both lighting up in aftershocks. ![]() ![]() It also produced a far-flung aftershock sequence that touched the San Andreas, but refused to cross the Garlock Fault.Ĭitation: Shinji Toda, and Ross Stein (2019), Ridgecrest earthquake shut down cross-fault aftershocks, Temblor, Ī remarkable illustration of how stress controls seismicity was handed to us by the Ridgecrest earthquake sequence. The Magnitude 7.1 earthquake abruptly halted aftershocks on the M 6.4 cross fault. ![]() By Shinji Toda, Ph.D., IRIDeS, Tohoku University, and Ross Stein, Ph.D., Temblor, Inc. ![]()
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