Comment on "self-similar earthquake triggering, Båth's law, and foreshock/aftershock magnitudes: Simulations, theory, and results for southern California" by P. M. Shearer

Abstract

Shearer [2012] finds three differences of the seismicity clustering in southern California compared to self-similar triggering models: (i) a significantly lower b-value for the aftershocks, (ii) a too large aftershock number, and (iii) a too large foreshock-aftershock ratio to be consistent with the Båth law. Based on these observations, the author concluded that the observed seismicity is not in agreement with self-similarity triggering and/or the observed clustering is not primarily caused by earthquake-to-earthquake triggering. However, I show that the observed lower b-value is likely related to incomplete recordings after mainshocks and that the apparently too large aftershock number does not disprove the self-similarity. Thus, only the enhanced foreshock-to-aftershock ratio seems to indicate some discrepancy to self-similar triggering. ©2013. American Geophysical Union. All Rights Reserved.