- Letter
- Published:
Source process of the recurrent Tokachi-oki earthquake on September 26, 2003, inferred from teleseismic body waves
Earth, Planets and Space volume 55, pages e21–e24 (2003)
Abstract
On September 26, 2003, a large earthquake with a magnitude of 8.0 occurred along the Kuril trench off Tokachi, Hokkaido, Japan. We investigated the source process by using teleseismic P- and SH-wave data. The main source parameters are as follows: the seismic moment 1.0 × 1021 Nm (Mw= 8.0); (strike, dip, rake) = (230°, 20°, 109°); the depth of initial break point 25 km; source duration 40 sec; and the maximum slip 5.8 m. We estimated the fault area to be 90 × 70 km2, the average slip 2.6 m, and the stress drop 5.0 MPa. This earthquake was an interplate earthquake associated with the subduction of the Pacific plate. The rupture propagated northward from a shallow to a deep region. In this area, a great earthquake (magnitude 8.2) occurred in 1952. We also made limited inversion of nearfield records of the 1952 event and found that the 2003 asperity was also ruptured in 1952. Our result suggests that the 2003 Tokachi-oki earthquake was a recurrent event of the 1952 Tokachi-oki earthquake.
References
DeMets, C., Oblique convergence and deformation along the Kuril and Japan trenched, J. Geophys. Res., 97, 17615–17625, 1992.
Hamada, N. and Y. Suzuki, Re-examination of focal area of the 1952 Tokachi-oki earthquake, Prog. Abstr. Seismol. Soc. Jpn., 2, A044, 2003 (in Japanese).
Hirata, K., E. Geist, K. Satake, Y. Tanioka, and S. Yamaki, Slip distribution of the 1952 Tokachi-oki earthquake (M 8.1) along the Kuril Trench deduced from tsunami waveform inversion, J. Geophys. Res., 108, 2196, doi:10.1029/2002JB001976, 2003.
Iwasaki, T., H. Shiobara, A. Nishizawa, T. Kanazawa, K. Suyehiro, N. Hirata, T. Urabe, and H. Shimamura, A detailed subduction structure in the Kuril trench deduced from ocean bottom seismographic refraction studies, Tectonophys., 165, 315–336, 1989.
Japan Meteorological Agency, http://www.jma.go.jp/JMAHP/jma/press/0309/30b/tunami.pdf, 2003 (in Japanese).
Katsumata, K., N. Wada, and M. Kasahara, Newly imaged shape of the deep seismic zone within the subducting Pacific plate beneath the Hokkaido corner, Japan-Kurile arc-arc junction, J. Geophys. Res, 2003 (in press).
Kikuchi, M. and H. Kanamori, Inversion of complex body waves—III, Bull. Seism. Soc. Am., 81, 2335–2350, 1991.
Kikuchi, M., M. Nakamura, and K. Yoshikawa, Source rupture processes of the 1944 Tonankai earthquake and the 1945 Mikawa earthquake derived from low-gain seismograms, Earth Planets Space, 55, 159–172, 2003.
Kikuchi, M. and H. Kanamori, Note on Teleseismic Body-Wave Inversion Program, http://www.eri.u-tokyo.ac.jp/ETAL/KIKUCHI/, 2003.
The Headquarters for Earthquake Research Promotion, http://www.jishin.go.jp/main/chousa/03marchishima/index.htm, 2003.
Yamanaka, Y. and M. Kikuchi, Asperity map along the subduction zone in northeastern Japan inferred from regional seismic data, J. Geophys. Res., 2003 (submitted).
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Yamanaka, Y., Kikuchi, M. Source process of the recurrent Tokachi-oki earthquake on September 26, 2003, inferred from teleseismic body waves. Earth Planet Sp 55, e21–e24 (2003). https://doi.org/10.1186/BF03352479
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1186/BF03352479