Online Program

Investigating Earthquake Magnitude Interdependency Through Stochastic Declustering (303037)

Keywords: earthquake magnitude, mainshock, aftershock, stochastic de-clustering, SDMISD

Recent research has shown that, for the larger earthquakes recorded (M greater than or equal to 5.2) within the global centroid moment tensor (gCMT), there is a positive correlation between the magnitudes of earthquakes and the magnitudes of their aftershocks (Nichols and Schoenberg 2014). Through a modification of model independent stochastic declustering (Marsan and Lengline 2008) and a more localized catalog provided by the Southern California Earthquake Data Center (SCEDC), the methodologies of Nichols and Schoenberg can be extended to catalogs complete with a much lower minimum magnitude of completeness (M greater than or equal to 2.2). Results indicate the positive correlation observed between larger earthquakes in the gCMT catalog and their aftershocks also is evident in the relationship between the magnitudes of earthquakes in the SCEDC data and their aftershocks. However, with the lower minimum magnitude of completeness found in the SCEDC catalog and with short periods of extreme earthquake activity evident within the data, the statistical power of the stochastic declustering algorithms to distinguish between mainshocks and aftershocks is diminished.