Co-seismic strain-steps associated with the 2004 off the Kii peninsula earthquakes-Observed with Ishii-type borehole strainmeters and quartz-tube extensometers

Author:

Asai Yasuhiro,Okubo Makoto,Ishii Hiroshi,Aoki Harumi,Yamauchi Tsuneo,Kitagawa Yuuichi,Koizumi Naoji

Abstract

Abstract The 2004 off the Kii peninsula earthquakes (Mj7.1 and Mj7.4) occurred at the Nankai trough, on 5 September 2004. Clear strain-steps associated with these earthquakes were observed with Ishii-type borehole strainmeters and quartz-tube extensometers in the Tokai and Kinki districts. We investigated the spatial and depth distribution of the observed principal strain changes and compared the observed strain-steps and theoretical calculations at all observatories. The following results were obtained: the observed strain-steps at all observatories are generally consistent with the polarities of the theoretical values, and the observed strain-step increases with depth at the same place. As for the Togari site, the following relationships are obtained: the strain-step and the tidal strains increase with depth and increasing of the modulus of elasticity, namely, hardness of rock. We consider that the geological structure around the observatory may cause a modification of the strain field.

Publisher

Springer Science and Business Media LLC

Subject

Space and Planetary Science,Geology

Reference15 articles.

1. Asai, Y., H. Aoki, T. Tanaka, Y. Kitagawa, and S. Azuma, Comparison of tidal changes of ground strain and groundwater level observed at clustered boreholes in the Tono region, central Japan, J. Geod. Soc. Japan, 47, 134–140, 2001.

2. Geographical Survey Institute, Fault models of the Off Kii-Peninsula Earthquakes, reported at the 161st meeting of the Coordinating Committee for Earthquake Prediction (CCEP), 2004 (in Japanese).

3. Hashimoto, M., K. Onoue, F. Ohya, Y. Hoso, K. Segawa, K. Sato, and Y. Fujita, Crustal deformations in Kii peninsula associated with the SE off the Kii peninsula earthquake sequence of September 5, 2004 derived from dense GPS observations, Earth Planets Space, 57, 185–190, 2005.

4. Ishii, H., T. Yamauchi, S. Matsumoto, Y. Hirata, and S. Nakao, Development of multi-component borehole instrument for earthquake prediction study: Some observed examples of precursory and co-seismic phenomena relating to earthquake swarms and application of the instrument for rock mechanics in Seismogenic process monitoring, edited by H. Oga-sawara, T. Yanagidani and M. Ando, pp. 365-377, A. A BALKEMA PUBL., 2002.

5. Ishii, H., T. Yamauchi, Y. Asai, M. Ohkubo, S. Matsumoto, and H. Aoki, Continuous multi-component monitoring of crustal activities by a newly developed instrument installed in a 1200 m depth borehole—The deepest multiple observation in the world consisting of stress, strain, tilt, seismic waves, geomagnetism, temperature, paper presented at IUGG XXIII General Assembly, Int. Union of Geod. And Geophys., Sapporo, JAPAN, 2003.

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