JpGU-AGU Joint Meeting 2017

Presentation information

[EE] Oral

S (Solid Earth Sciences) » S-SS Seismology

[S-SS05] [EE] earthquake statistics, physics-based earthquake forecasting, and earthquake model testing

Wed. May 24, 2017 1:45 PM - 3:15 PM A05 (Tokyo Bay Makuhari Hall)

convener:Danijel Schorlemmer(GFZ German Research Centre for Geosciences), Naoshi Hirata(Earthquake Research Institute, the University of Tokyo), Matt Gerstenberger(GNS Science), Hiroshi Tsuruoka(Earthquake Research Institute, Tokyo Univ.), Jiancang Zhuang(Institute of Statistical Mathematics), Chairperson:Hiroshi Tsuruoka(Earthquake Research Institute, Tokyo Univ.), Chairperson:Kazuyoshi Nanjyo(University of Shizuoka)

1:45 PM - 2:00 PM

[SSS05-01] HIST-ETAS models - revisited with emphasis on background seismicity

*Yosihiko Ogata1 (1.Research Organization of Information and Systems, The Institute of Statistical Mathematics)

Keywords:space-time ETAS model, Delaunay triangulation, background seismicity

It has been passed about 15 years since the hierarchical space-time ETAS (HIST-ETAS) models have been proposed; and the short- and intermediate-term earthquake forecasts in and around Japan using the HIST-ETAS model is under examining for 8 years by the Testing Center of the Collaborative Study of Earthquake Predictability (CSEP).

Some parameters of the HIST-ETAS model are characterized by a two dimensional piecewise linear function whose value at any location is linearly interpolated by the values at the nearest three earthquake locations that consists a Delaunay triangle. The solutions of the parameter functions are obtained through the inversion of the log-likelihood function of the space-time earthquake data, with certain smoothness constraints. This is suited not only for high resolution inversion in the region of clustering of earthquakes but also accurate space-time forecast in the active stage of seismicity.

Among the parameters of the HIST-ETAS models, we are primary interested in that of the background seismicity. This values can regionally vary in the range of several orders is in a seismogenic zone, but the solutions are confirmed to be independent of observed periods. Hence this is quite useful for the secular prediction of large earthquake locations, in conjunction with Gutenberg-Richter distribution where the b-value is also location dependent.

In this talk, I will show examples of such forecast in Japan inland and vicinity, California, and the global seismicity. The relevant software codes and manual can be obtained by the request mail to