3D models of seismicity beneath the Greater Tokyo Area

Yosihiko Ogata, Koichi Katsura, Hiroshi Tsuruoka, & Naoshi Hirata

Submitted August 10, 2018, SCEC Contribution #8390, 2018 SCEC Annual Meeting Poster #036

We consider a 3D models for the short-term forecast beneath the Metropolitan area (Kanto region) by extending the epidemic-type aftershock sequence (ETAS) models, taking account of the induced effect from the 2011 Tohoku-Oki earthquake of M9. Especially, owing to the configuration of the three tectonic plates beneath the Kanto region, location-dependent space-time ETAS model for the seismicity in 3D space (longitude, latitude and depth) down to 100km depth is required. Moreover, we also consider 3D location-dependent b-value for Gutenberg-Richter (GR) law of magnitude frequency. We use the 3D Delaunay-based piecewise linear functions to estimate such parameter functions. Then, based on the long-term hypocenter data beneath the focal Kanto Region, we simultaneously solve the background rates, the aftershock productivity rates, alpha-value of magnitude effects, p-value for the decay rates, b-value of the GR law, and the induced factor from the Tohoku-Oki Earthquake of M9. The optimally inverted 3D spatial image of each of such characteristic parameters represents quite interestingly different characteristics among the volume in shallow crust, and surface boundaries of subducting Pacific Plate and Philippine Sea Plates. Furthermore, the location-dependent external triggering factor shows how strong or weak the induced effect from the M9 earthquake resulted in and on each zone beneath Kanto Region.

Key Words
ETAS model, b-values, induce factor by the M9 event

Ogata, Y., Katsura, K., Tsuruoka, H., & Hirata, N. (2018, 08). 3D models of seismicity beneath the Greater Tokyo Area. Poster Presentation at 2018 SCEC Annual Meeting.

Related Projects & Working Groups
Collaboratory for the Study of Earthquake Predictability (CSEP)