%0 Journal Article
%T Aftershock identification
%A Ilya Zaliapin
%A Andrei Gabrielov
%A Vladimir Keilis-Borok
%A Henry Wong
%J Physics
%D 2007
%I arXiv
%R 10.1103/PhysRevLett.101.018501
%X Earthquake aftershock identification is closely related to the question "Are aftershocks different from the rest of earthquakes?" We give a positive answer to this question and introduce a general statistical procedure for clustering analysis of seismicity that can be used, in particular, for aftershock detection. The proposed approach expands the analysis of Baiesi and Paczuski [PRE, 69, 066106 (2004)] based on the space-time-magnitude nearest-neighbor distance $\eta$ between earthquakes. We show that for a homogeneous Poisson marked point field with exponential marks, the distance $\eta$ has Weibull distribution, which bridges our results with classical correlation analysis for unmarked point fields. We introduce a 2D distribution of spatial and temporal components of $\eta$, which allows us to identify the clustered part of a point field. The proposed technique is applied to several synthetic seismicity models and to the observed seismicity of Southern California.
%U http://arxiv.org/abs/0712.1303v1