11:00 AM - 11:15 AM
[SSS11-14] On the attenuation characteristics of peak ground motion from three Mw7 class intraplate earthquakes along the Japan Trench
Keywords:Peak ground motion, Attenuation characteristics, Intraplate earthquake, 2021 Mw7.1 Fukushima-oki earthquake, Ground motion prediction equation (GMPE)
Including the February 13, 2021 Mw 7.1 Fukushima-oki earthquake, there are three well recorded Mw 7 class intraplate earthquake that occurred along the Japan Trench. The other two earthquakes are the 2003 Mw 7.0 Miyagi-ken-oki earthquake and the 2011 Mw 7.1 Miyagi-ken-oki earthquake. In this study, we’ll compare the attenuation characteristics of peak ground motions recorded during the three earthquakes and discuss the differences among them.
The data used in this study for all the three earthquakes are derived by K-NET and KiK-net. All the waveform data are processed by a bandpass filter with a lower cut off frequency at 0.1 Hz and higher one at 10 Hz. The acceleration waveforms are integrated to velocity waveforms. PGA and PGV are defined as the larger one between the two horizontal components. The closest distance from the seismic fault to the observation station is defined as the source distance. The source models used for the calculation of source distances are those proposed by Aoi et al. (2003), Harada and Kamae (2011) and the Kubo et al.(2021), respectively. Mw is adopted from the online catalog by the Global CMT Project. The source depth used here are 70km, 59km and 52km for the 2003 Mw 7.0 Miyagi-ken-oki earthquake, the 2011 Mw 7.1 Miyagi-ken-oki earthquake and the 2021 Mw 7.1 Fukushima-oki earthquake, respectively.
We compared the PGAs and PGVs observed during the 2021 Mw 7.1 Fukushima-oki earthquake with the 2003 Mw 7.0 Miyagi-ken-oki earthquake (shown in Figure 1), and with the 2011 Mw 7.1 Miyagi-ken-oki earthquake (shown in Figure 2). As a reference, in the figures, the values calculated by the GMPE proposed by Si and Midorikawa (1999) are also plotted. The figures show that, (1) the data for the 2021 Mw7.1 Fukushima-oki earthquake are generally similar to those for the 2003 Mw 7.0 Miyagi-ken-oki earthquake, but relatively weaker than those for the 2011 Mw 7.1 Miyagi-ken-oki earthquake at distances shorter than about 200 km; (2) the observations at distances farther than about 150 km are generally consistence with the prediction by GMPE, but stronger than GMPE at shorter distances; (3) higher attenuation for stations at far distances reported for the 2011 Geiyo earthquake are not significantly observed for all the three earthquakes in this study.
References
Aoi S., Sekiguchi H., Kunugi T., Honda R. and Fujiwara H.(2003), https://www.kyoshin.bosai.go.jp/kyoshin/news/miyagi/.
Harada and Kamae (2011) , https://www.rri.kyoto-u.ac.jp/jishin/eq/tohoku2/20110407miyagioki_slab.pdf.
Kubo H., Suzuki W., Aoi S. and Sekiguchi H. (2021) , https://www.kyoshin.bosai.go.jp/kyoshin/topics/FukushimakenOki_20210213/inversion/inv_index.html.
Si, H. and Midorikawa, S. (1999). J. Struct. Constr. Eng. AIJ. 523,63-70 (in Japanese with English Caption and Abstract).
Acknowledgements
The author thanks NIED to provide recordings by K-NET and KiK-net.
The data used in this study for all the three earthquakes are derived by K-NET and KiK-net. All the waveform data are processed by a bandpass filter with a lower cut off frequency at 0.1 Hz and higher one at 10 Hz. The acceleration waveforms are integrated to velocity waveforms. PGA and PGV are defined as the larger one between the two horizontal components. The closest distance from the seismic fault to the observation station is defined as the source distance. The source models used for the calculation of source distances are those proposed by Aoi et al. (2003), Harada and Kamae (2011) and the Kubo et al.(2021), respectively. Mw is adopted from the online catalog by the Global CMT Project. The source depth used here are 70km, 59km and 52km for the 2003 Mw 7.0 Miyagi-ken-oki earthquake, the 2011 Mw 7.1 Miyagi-ken-oki earthquake and the 2021 Mw 7.1 Fukushima-oki earthquake, respectively.
We compared the PGAs and PGVs observed during the 2021 Mw 7.1 Fukushima-oki earthquake with the 2003 Mw 7.0 Miyagi-ken-oki earthquake (shown in Figure 1), and with the 2011 Mw 7.1 Miyagi-ken-oki earthquake (shown in Figure 2). As a reference, in the figures, the values calculated by the GMPE proposed by Si and Midorikawa (1999) are also plotted. The figures show that, (1) the data for the 2021 Mw7.1 Fukushima-oki earthquake are generally similar to those for the 2003 Mw 7.0 Miyagi-ken-oki earthquake, but relatively weaker than those for the 2011 Mw 7.1 Miyagi-ken-oki earthquake at distances shorter than about 200 km; (2) the observations at distances farther than about 150 km are generally consistence with the prediction by GMPE, but stronger than GMPE at shorter distances; (3) higher attenuation for stations at far distances reported for the 2011 Geiyo earthquake are not significantly observed for all the three earthquakes in this study.
References
Aoi S., Sekiguchi H., Kunugi T., Honda R. and Fujiwara H.(2003), https://www.kyoshin.bosai.go.jp/kyoshin/news/miyagi/.
Harada and Kamae (2011) , https://www.rri.kyoto-u.ac.jp/jishin/eq/tohoku2/20110407miyagioki_slab.pdf.
Kubo H., Suzuki W., Aoi S. and Sekiguchi H. (2021) , https://www.kyoshin.bosai.go.jp/kyoshin/topics/FukushimakenOki_20210213/inversion/inv_index.html.
Si, H. and Midorikawa, S. (1999). J. Struct. Constr. Eng. AIJ. 523,63-70 (in Japanese with English Caption and Abstract).
Acknowledgements
The author thanks NIED to provide recordings by K-NET and KiK-net.