Features of Seismic Sequences Are Similar in Different Crustal Tectonic Regions

Abstract

We investigate the existence of possible differences in the earthquake clustering process in three areas related to distinct tectonic regimes: Italy, southern California, and Japan. At first, we separate the triggered and background components of seismicity of the three catalogs. Then, we analyze statistically the space–time domain of the earthquake clusters to identify possible variations in the triggering properties across the considered regions. Finally, we characterize the background seismicity in the three seismic catalogs to test whether it can be satisfactorily described by a time‐homogeneous Poisson process. Overall, our analysis shows similar features of the seismicity in the three tectonic regions. Specifically, we find common average earthquake clustering properties in the three tectonic regions superimposed on a background seismicity described by the Poisson process, with a time‐dependent rate. We conclude that, at least for the analyzed active seismic crustal regions, the tectonic regime does not seem to play a key role in affecting the average spatiotemporal clustering properties. Remarkably, we reach the same conclusion when inspecting the influence of subregions with homogeneous deformation style.