A0794
Title: Extend the ETAS model step-by-step
Authors: Jiancang Zhuang - Institute of Statistical Mathematics (Japan) [presenting]
Abstract: The space-time epidemic-type aftershock sequence (ETAS) model, which is a special type of marked Hawkes process, has been widely used as a standard model to analyze local, regional, or even global seismicity. The assumptions of this model include: (1) The magnitudes are identically independently distributed and also independent from other components. (2) The background seismicity is stationary in time but nonhomogeneous in space. (3) Each event, no matter whether it is a background event or is triggered by other shocks, triggers its own offspring independently according to some probability rules. Many features of seismicity that are not included in the ETAS model have been revealed by analysis of seismic data from different regions, indicating that the ETAS model should be extended to incorporate more information on seismicity. The current developments on the extension of the ETAS model are summarized, including (1) Non-stationary background rates, such as long-term trend and seasonality, (2) Earthquake depth, (3) Geometry of earthquake rupture, (4) Earthquake focal mechanisms, (5) Magnitude dependence in triggering, and (6) Depth dependent clustering. In the implementations of the extensions, stochastic declustering and stochastic reconstruction have been used as basic tools to estimate the non-parametric parts. The current achievements are outlined, and a brief perspective of possible future developments is given.
