[S-TT40] Seismic Big Data Analysis Based on the State-of-the-Art of Bayesian Statistics

[STT40-02] An MCMC approach for determining earthquake hypocenters around a structural boundary and its application to aftershocks of the 2004 Mid-Niigata Prefecture Earthquake

*Takahiro Shiina¹, Masayuki Kano², Aitaro Kato³ (1.National Institute of Advanced Industrial Science and Technology, 2.Tohoku University, 3.Earthquake Research Institute, The University of Tokyo)

Keywords:MCMC method, Crustal earthquake, 1-D velocity model, the 2004 Mid-Niigata Prefecture Earthquake

Determination of earthquake hypocenters is the fundamental analysis in seismology. The crustal seismicity often concentrates around a structural boundary. Across such the structural boundary, seismic velocity horizontally varies to reflect spatial variations of crustal materials. Therefore, the analysis that simultaneously estimates earthquake hypocenters and velocity models was necessary to accurately determine earthquake hypocenters around the structural boundary.
Shiina and Kano [accepted, GJI] proposed a method based on the Markov chain Monte Carlo (MCMC) method for determining earthquake hypocenters and 1-D velocity models around the structural boundary. The proposed method realized the clustering of stations reflecting velocity structures beneath the station network.
In this presentation, we introduce the outline of the method proposed by Shiina and Kano [accepted] and demonstrate its performance by numerical experiments. Moreover, we tried to estimate distributions of aftershocks of the 2004 Mid-Niigata Prefecture Earthquake and the 2007 Niigataken Chuetsu-oki Earthquake [e.g., Kato et al. 2009] by the proposed method.

Acknowledgement: We thank the Group for the Aftershock Observations of the 2007 Niigataken Chuetsu-oki Earthquake for allow to use their observation data. This study supported by JST CREST [JPMJCR1763].