Detection state of stress at a fault from focal mechanism data ? application to Kego fault-

Satoshi MATSUMOTO; Masahiro MIYAZAKI; Hiroshi SHIMIZU

Presentation information

Oral

Symbol S (Solid Earth Sciences) » S-SS Seismology

[S-SS30] Earthquake Source Processes and Physics of Earthquakes

Mon. May 25, 2015 11:00 AM - 12:45 PM A05 (APA HOTEL&RESORT TOKYO BAY MAKUHARI)

Convener:*Ryosuke Ando(Graduate School of Science, University of Tokyo), Yuko Kase(Active Fault and Earthquake Research Center, AIST, GSJ), Chair:Yuko Kase(Active Fault and Earthquake Research Center, AIST, GSJ), Takehito Suzuki(Department of Physics and Mathematics, Aoyama Gakuin University)

12:39 PM - 12:42 PM

[SSS30-P09] Detection state of stress at a fault from focal mechanism data ? application to Kego fault-

3-min talk in an oral session

*Satoshi MATSUMOTO¹, Masahiro MIYAZAKI¹, Hiroshi SHIMIZU¹ (1.Institute of Seismology and Volcanology, Kyushu Univ.)

Keywords:stress field, state of stress, focal mechanism, Kego fault

One of the approaches used to evaluate the potential of an earthquake occurrence is the detection of the stress concentration at an earthquake fault. The stress fields for pre- and post-seismic event stages differ. However, this change cannot provide information regarding the potential for an earthquake to occur. Matsumoto et al. (2014) have proposed a detection method for states of stress that uses focal mechanism data of microearthquakes. The state of stress in this study can be defined by a moment tensor equivalent to the stress concentration normalized by differential stress. We apply this method to actual focal mechanism data from the 2005 Fukuoka earthquake and around the Kego fault, Kyushu, Japan, and discuss the presence of stress concentration around the earthquake fault before the mainshock.