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Long-range earthquake forecasting allowing for aftershocks

David A. Rhoades

Published 2009, SCEC Contribution #1239

An earthquake occurrence model aimed at forecasting mainshocks can be adjusted to allow for the occurrence of aftershocks conforming to well-known empirical relations describing their temporal decay, magnitude distribution and spatial extent. Modifications are proposed to the EEPAS (Every Earthquake a Precursor According to Scale) long-range forecasting model to allow for the occurrence of aftershocks of predicted events. Using earthquake catalogues of California and the Kanto region, central Japan, versions of the modified and original EEPAS model are fitted to a period of about 10 years and independently tested on a later period of about 10 years of each catalogue. For the testing period, the increase in the log likelihood per earthquake of the modified models over their original counterparts is about 0.1 on average. This gives preliminary confirmation of the efficacy of the modifications. Versions of the modified model will be submitted to regional testing centres of the Collaboratory for the Study of Earthquake Predictability for further independent performance testing in real time.

Rhoades, D. A. (2009). Long-range earthquake forecasting allowing for aftershocks. Geophysical Journal International, 174, 244-256.