Consistency of seismogenic stress field of preshocks to the tectonic stress field before eight earthquakes (MW≥6.0) in southern California of United States from 1981 to 2011
Han Xiaoming
Rong Dailu
Abstract：This paper defines an index called “concentration ratio of P axis dis-tribution”used for analyzing the variation of focal mechanisms of small earth-quakes before moderate-strong earthquakes.And then based on the focal mech-anism solutions of earthquakes in southern California in the period of 1981—2011,this paper investigates the seismogenic stress field of small events concen-trating on the local tectonic stress field before eight main shocks (MW≥6.0)in the southern California.The results show a phenomenon that the “concentra-tion ratio of P axis distribution”has a minimum was observed before seven earthquakes,that is,the seismogenic stress field of small events concentrates on the local tectonic stress field.It provides a method for the risk prediction of moderate-strong earthquakes.
Keywords：concentration ratio of P axis distributionfocal mechanism solutionsouthern California of United Statesseismogenic stress field
Publication Date：2015-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：11( 948-958 )