5:15 PM - 6:45 PM
[SSS10-P14] Examination of ground amplification factor etc. based on microtremor array observations at seismic stations
Keywords:underground structure model, strong ground motion, microtrmor array observation, S-wave velocity profile
The National Research Institute for Earth Science and Disaster Prevention (NIED) has so far developed shallow and deep integrated ground structure models for the Kanto and Tokai regions for the purpose of broadband strong ground motion evaluation. AVS30 (m/s) and ground amplification factor (maximum velocity amplification factor) were published in March 2021 (December 2023 for the Tokai region) on the NIED website J -shis published by the National Research Institute for Earth Science and Disaster Prevention (NIED). In the Kanto region, a total of more than 310,000 borehole data were collected and organized, and about 14,000 microtremor arrays were observed and analyzed at intervals of about 1 to 2 km.
Currently, evaluation of ground amplification factor of surface ground in Japan is being conducted by Fujimoto and Midorikawa (2006). The AVS30 used for ground amplification factor evaluation is partly calculated based on PS logging results from K-NET and KiK-net seismic stations of the National Research Institute for Earth Science and Disaster Prevention (NIED). However, K-NET (about 1,000 sites) only records 5 to 20 m of drilling, and no surveys have been conducted deeper than 20 m. For KiK-net (about 700 sites), although PS logging has been conducted at depths of 100 m or more, the accuracy of the surface ground is not high, given the method of obtaining logging data. is not high. In this study, microtremor array (small array) surveys were conducted at more than 1,300 K-NET and KiK-net seismic stations nationwide, and the obtained S-wave velocity structure models were examined. The purpose of this study is to evaluate the relationship between AVS30 and ground amplification factor based on the S-wave velocity structure obtained from these results, and to propose a new ground amplification factor that takes into account periodic characteristics.
Currently, evaluation of ground amplification factor of surface ground in Japan is being conducted by Fujimoto and Midorikawa (2006). The AVS30 used for ground amplification factor evaluation is partly calculated based on PS logging results from K-NET and KiK-net seismic stations of the National Research Institute for Earth Science and Disaster Prevention (NIED). However, K-NET (about 1,000 sites) only records 5 to 20 m of drilling, and no surveys have been conducted deeper than 20 m. For KiK-net (about 700 sites), although PS logging has been conducted at depths of 100 m or more, the accuracy of the surface ground is not high, given the method of obtaining logging data. is not high. In this study, microtremor array (small array) surveys were conducted at more than 1,300 K-NET and KiK-net seismic stations nationwide, and the obtained S-wave velocity structure models were examined. The purpose of this study is to evaluate the relationship between AVS30 and ground amplification factor based on the S-wave velocity structure obtained from these results, and to propose a new ground amplification factor that takes into account periodic characteristics.