An ETAS model with varying productivity rates

David S. Harte

Published June 19, 2014, SCEC Contribution #6081

We present an epidemic type aftershock sequenc (ETAS) model where the offspring rates vary both spatially and temporally. This is achieved by distinguishing between those space–time volumes where the interpoint space and time distances are small, and those where they are considerably larger.

We also question the nature of the background component in the ETAS model. Is it simply a temporal boundary correction (t = 0) or does it represent an additional tectonic process not described by the aftershock component?

The form of these stochastic models should not be considered to be fixed. As we accumulate larger and better earthquake catalogues, GPS data, strain rates, etc., we have the ability to ask more complex questions about the nature of the process. By fitting modified models consistent with such questions, we should gain a better insight into the earthquake process. Hence, we consider a sequence of incrementally modified ETAS type models rather than ‘the’ ETAS model.

Harte, D. S. (2014). An ETAS model with varying productivity rates. Geophysical Journal International, 198(1), 270-284. doi: 10.1093/gji/ggu129.