Distribution of the largest aftershocks in branching models of triggered seismicity: theory of the universal Båth law.
Distribution of the largest aftershocks in branching models of triggered seismicity: theory of the universal Båth law.
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触发地震活动分支模型中最大余震的分布:普遍巴斯定律理论。
DOI:
10.1103/physreve.71.056127
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发表时间:
2005
期刊:
影响因子:
--
通讯作者:
D. Sornette
中科院分区:
文献类型:
--
作者:
A. Saichev;D. Sornette
Using the epidemic-type aftershock sequence (ETAS) branching model of triggered seismicity, we apply the formalism of generating probability functions to calculate exactly the average difference between the magnitude of a mainshock and the magnitude of its largest aftershock over all generations. This average magnitude difference is found empirically to be independent of the mainshock magnitude and equal to 1.2, a universal behavior known as Båth's law. Our theory shows that Båth's law holds only sufficiently close to the critical regime of the ETAS branching process. Allowing for error bars +/- 0.1 for Båth's constant value around 1.2, our exact analytical treatment of Båth's law provides new constraints on the productivity exponent alpha and the branching ratio n: 0.9 approximately < alpha < or =1. We propose a method for measuring alpha based on the predicted renormalization of the Gutenberg-Richter distribution of the magnitudes of the largest aftershock. We also introduce the "second Båth law for foreshocks:" the probability that a main earthquake turns out to be the foreshock does not depend on its magnitude rho.