Abstract
Hypocenters of main shocks and aftershocks of the 1933 M=7.1, 1936 M=7.4, 1937 M=7.1 and 1978 M=7.4 Miyagi-oki earthquakes are relocated using S-P times reported in the Seismological Bulletin of the Japan Meteorological Agency (JMA) and those re-read from original smoked-paper seismograms observed at the Mizusawa station of the National Astronomical Observatory of Japan (NAOJ) and the Mukaiyama station of Tohoku University. In order to reduce the error caused by inaccuracies of the arrival times and the small number of seismic observation stations, we determined the hypocenters by using a grid search method that assumed that the events occurred at the boundary between the subducting Pacific plate and the overriding plate. The main shock epicenters of these four earthquakes were determined to be close to each other, while the distributions of their aftershocks seem to disperse on the upper boundary of the Pacific plate. These distributions show that aftershock areas of the 1933, 1936 and 1937 events partly overlap with that of the 1978 event and occupy its easternmost, central and westernmost portions, respectively. This result suggests that the 1933, 1936 and 1937 events possibly ruptured a part of the source area of the 1978 event, i.e., its eastern, central and western portions, respectively.
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References
Hasegawa, A., N. Umino, and A. Takagi, Double-planed structure of the deep seismic zone in the northeastern Japan arc, Tectonophysics, 47, 43–58, 1978.
Hasegawa, A., N. Uchida, T. Igarashi, T. Matsuzawa, T. Okada, S. Miura, and Y. Suwa, Asperities and Quasi-static Slip on the Subducting Plate Boundary East off Tohoku, NE Japan, SEIZE volume, Columbia Univ. Press., 2005.
Hino, R., Y. Yamamoto, M. Nishino, T. Kanazawa, T. Yamada, K. Nakahigashi, K. Mochizuki, M. Shinohara, G. Aoki, M. Tanaka, E. Araki, S. Kodaira, G. Fujie, and Y. Kaneda, Hypocenter distribution of the 2005 Miyagi-oki earthquake and its aftershocks by OBS observation, PM02, Programme and abstracts the Seismological Society of Japan 2005, Fall meeting, 2005.
Kanamori, H., M. Miyazawa, and J. Mori, Investigation of the earthquake sequence off Miyagi prefecture with historical seismograms, Earth Planets Space, 58, this issue, 1533–1541, 2006.
Matsuzawa, T., N. Uchida, T. Igarashi, T. Okada, and A. Hasegawa, Repeating earthquakes and quasi-static slip on the plate boundary east off northeastern Honshu, Japan, Earth Planets Space, 56, 803–811, 2004.
Nagai, R., M. Kikuchi, and Y. Yamanaka, Comparative study on the source process of recurrent large earthquakes in Sanriku-oki region: the 1968 Tokachi-oki and the 1994 Sanriku-oki earthquakes, J. Seismol. Soc. Jpn., 54, 267–280.
Okada, T., T. Matsuzawa, and A. Hasegawa, Comparison of source areas of M4.8+/-0.1 repeating earthquakes off Kamaishi, NE Japan—Are asperities persistent features?, Earth Planet Sci. Lett., 213, 361–374, 2003.
Okada, T., T. Yaginuma, N. Umino, T. Kono, T. Matsuzawa, S. Kita, and A. Hasegawa, The 2005 M7.2 Miyagi-oki earthquake, NE Japan: Possible Re-rupturing of one of asperities that caused the previous M7.4 earthquake, Geophys. Res. Lett, 32, L24302, doi:10.1029/2005GL024613, 2005.
Tanioka, Y. and Y. Hasegawa, Re-analysis of the source process of the 1936 Miyagi-oki earthquake using tsunami waveforms, P128, Programme and abstracts the Seismological Society of Japan 2005, Fall meeting, 2005.
The Headquarters for Earthquake Research Promotion, MEXT, Japan, Long-term evaluation of the Miyagi-Oki earthquake, http://www.jishin.go.jp/main/index.html, 2001 (in Japanese).
The International Latitude Observatory of Mizusawa, Seismological observations at Mizusawa for the period between 1902~1967, pp. 379, 1984.
Waldhauser, F. and W. L. Ellsworth, A double-difference earthquake location algorithm: method and application to the Northern Hayward fault, Bull. Seismol. Soc. Am., 90, 1353–1368, 2000.
Yamanaka, Y. and M. Kikuchi, Source process of the recurrent Tokachioki earthquake on September 26, 2003, inferred from teleseismic body waves, Earth Planets Space, 55, e21–e24, 2003.
Yamanaka, Y. and M. Kikuchi, Asperity map along the subduction zone in northeastern Japan inferred from regional seismic data, J. Geophys. Res., 109, 2003 JB002683, 2004.
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Umino, N., Kono, T., Okada, T. et al. Revisiting the three M~7 Miyagi-oki earthquakes in the 1930s: possible seismogenic slip on asperities that were re-ruptured during the 1978 M=7.4 Miyagi-oki earthquake. Earth Planet Sp 58, 1587–1592 (2006). https://doi.org/10.1186/BF03352666
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DOI: https://doi.org/10.1186/BF03352666