Article | Open | Published:
Differences in ground motion and fault rupture process between the surface and buried rupture earthquakes
Earth, Planets and Spacevolume 56, pages3–14 (2004)
We have studied differences in ground motion and fault rupture characteristics between surface rupture and buried rupture earthquakes. We found that the ground motion generated by buried rupture in the period range around 1 second is on average 1.5 times larger than the average empirical relationship. In contrast, ground motion from earthquakes that rupture the surface is 1.5 times smaller in the same period range. This phenomenon is considered to be caused by differences in fault rupture process between the two types of earthquakes. To examine possible reasons of the above effect we analyzed source slip distribution data derived from waveform inversions, and divided them into two groups: surface rupture and buried rupture earthquakes. It was found that the large slip areas (asperities) of surface rupture earthquakes are concentrated in the depth range shallower than about 5 km. In contrast, large slip areas of buried rupture earthquakes are spread over the depth deeper than 5 km. We also found that the total rupture area of buried rupture earthquakes is 1.5 times smaller than that of surface rupture earthquakes having the same seismic moment, and that deep asperities have about 3 times larger effective stress drops and 2 times higher slip velocities than shallow asperities. These observations are verified by numerical simulations using stochastic Green’s function method.
Abrahamson, N. A. and W. J. Silva, Empirical response spectral attenuation relations for shallow crustal earthquake, Seism. Res. Lett., 68, 94–127, 1997.
Boore, D., Stochastic simulation of high-frequency ground motions based on seismological models of the radiation spectra, Bull. Seism. Soc. Am., 73, 1865–1894, 1983.
Dalguer, L. A. and K. Irikura, Generation of tensile cracks during a 3D dynamic shear rupture propagation, Japan Earth and Planetary Science Joint Meeting, S042-P017 (CD-ROM), 2002.
Dalguer, L. A., K. Irikura, and J. D. Riera, Simulation of tensile crack generation by three-dimensional dynamic shear rupture propagation during an earthquake, J. Geophys. Res., 108(B3), 2144, doi:10.1029/2001JB001738, 2003.
Eshelby, J. D., The determination of the elastic field of and ellipsoidal inclusion, and related problems, Proc. Roy. Soc., A241, 376–396, 1957.
Hartzell, S. H. and T. H. Heaton, Inversion of strong ground motion and teleseismic waveform data for the fault rupture history of the 1979 Imperial Valley, California, earthquake, Bull. Seism. Soc. Am., 73, 1,553–1,583, 1983.
Irikura, K., H. Miyake, T. Iwata, K. Kamae, T. Kagawa, and K. Miyakoshi, A recipe of strong motion prediction for scenario earthquake, AGU Fall Meeting, S31C-01, 2001.
Iwata, T., H. Sekiguchi, and A. Pitarka, Source and site effects on strong ground motions in near-source area during the 1999 Chi-Chi, Taiwan, earthquake, AGU Fall Meeting, S72-P05, 2000.
Kamae, K. and K. Irikura, Prediction of site-specific strong ground motion using semi-empirical methods, 10WCEE, 801–806, 1992.
Miyakoshi, K., T. Kagawa, H. Sekiguchi, T. Iwata, and K. Irikura, Source characterization of inland earthquakes in Japan using source inversion results, 12WCEE, 1850, CD-ROM, 2000.
Sekiguchi, H. and T. Iwata, Source process inversion and near-source ground motion simulation of the 2000 Tottoriken-Seibu, Japan, earthquake (MW6.8), AGU fall meeting, S42C-0654, 2001.
Sekiguchi, H. and T. Iwata, Rupture process of the 1999 Kocaeli, Turkey earthquake estimated from strong-motion waveforms, Bull. Seism. Soc. Am., 92, 300–311, 2002.
Shimazaki, K., Small and large earthquake: the effects of thickness of seismogenic layer and the free surface, in Earthquake Source Mechanics, AGU Monograph, 37 (Maurice Ewing Ser. 6), edited by S. Das, J. Boaghtwright, and C. H. Sholz, pp. 209–216, 1986.
Somerville, P. G., Magnitude scaling of the near fault rupture directivity pulse, Phys. Earth Planet. Int., 137, 201–212, 2003.
Somerville, P. G., K. Irikura, R. Graves, S. Sawada, D. Wald, N. Abrahamson, Y. Iwasaki, T. Kagawa, N. Smith, and A. Kowada, Characterizing earthquake slip models forthe prediction of strong ground motion, Seism. Res. Lett., 70, 59–80, 1999.
Wald, D. J. and T. H. Heaton, Spatial and temporal distribution of slip of the 1992 Landers, California earthquake, Bull. Seism. Soc. Am., 84, 668–691, 1994.
Watanabe, M., T. Sato, and K. Dan, Scaling relations of fault parameters for inland earthquakes, 10th Jpn. Earthq. Eng. Symp., 583–588, 1998.
Wells, D. L. and K. J. Coppersmith, New empirical relationships among magnitude, rupture length, rupture width, rupture area, and surface displacement, Bull. Seism. Soc. Am., 84, 974–1002, 1994.
Yoshida, S. and K. Koketsu, Simultaneous inversion of waveform and geodetic data for the rupture process of the 1984 Naganoken-Seibu, Japan, earthquake, Geophys. J. Int., 103, 355–362, 1990.