Grid search of AMR for three California earthquakes

Figure 2.5: Grid search analysis of AMR for Kern County and Loma Prieta
\epsfig{file=guilhem_1_fig1.eps, width=7cm}\end{center}\end{figure}

Figure 2.6: Examples of comparison of maps of c-values from AMR circular grid search and of state of stress (bars) for 1975 and 1995.

Figure 2.5 presents two different maps for two large earthquakes of California: Kern County in 1952 and Loma Prieta in 1989. Each map shows the c-values obtained by a grid search analysis over southern California using the same parameters used by Bowman et al. (1998): radius of the circular search, period of time and magnitude range. The location of the mainshock is indicated by the star; the seismicity used in the search is represented by black dots.

The first grid search analysis was done with the goal of testing the concept of AMR and to answer the question: Can one find other regions of small c-values with the same parameters outside of the mainshock area?

On the contrary, the two mainshocks are located in the main areas of small c-values at the time of the respective main shocks. The choice of AMR parameters made by Bowman does not result in other potential regions of apparent AMR. However we still have to adjust the three parameters according to the mainshock we study.

Berkeley Seismological Laboratory
215 McCone Hall, UC Berkeley, Berkeley, CA 94720-4760
Questions or comments? Send e-mail:
© 2007, The Regents of the University of California