Name : KOKETSU,  Kazuki
                    Position : Associate Professor
                    Division/Center : Division of Disaster Mitigation Science
                    Research Area : Strong Motion Seismology, Seismic Wave Theory
                    homepage  : http: //saigai.eri.u-tokyo.ac.jp/saigai/ouyou.html
 
 
 
 

    1.Seismological Study on Near-Source Ground Motions
       The 1995 Kobe (Hyogo-ken Nanbu) earthquake revealed that strong ground motions in a source region consist of fault-normal
       seismic pulses with rather long period (1s〜several seconds) and short duration. This feature has been understood as a result of the
       directivity effect of fault rupture propagation from the comparison with Californian strong motion records.
    2.Complex Fault Rupture Processes as Sources of Strong Ground Motions
       Since complex fault rupture processes must generate strong ground motions, their high-precision and high-resolution images have
       been derived by comprehensive analyses of various datasets such as geodetic data, strong motion records and teleseismic body
       waves for the 1984 Nagano-ken Seibu and 1995 Kobe earthquakes (Yoshida et al., 1996).
    3.Complex Underground Structures as Sources of Strong Ground Motions
       Since complex underground structures must also generate strong ground motions through amplification and waveform deformation,
       new methods of seismic tomography and ray tracing have been developed to explore high-precision and high-resolution underground
       images, and they have been applied to the Pacific slab and the Kanto basin (Koketsu & Sekine, 1998; Koketsu & Higashi, 1992).
    4.Numerical Simulation of Strong Ground Motions
       In order to evaluate past strong motions or estimate future ones with reality, new theories and computational methods have been
       developed and applied to the simulation of strong ground motion causing the Hanshin-Awaji earthquake disaster (Furumura &
       Koketsu, 1998).
 

Publications :

      Koketsu, K., S. Yoshida and H. Higashihara, A fault model of the 1995 Kobe earthquake derived from the GPS data on the Akashi Kaikyo
      Bridge and other datasets, Earth Planets Space, 50, 803-811, 1998.

      Yoshida, S., K. Koketsu, B. Shibazaki, T. Sagiya, T. Kato and Y. Yoshida, Joint inversion of the near- and far-field waveforms and geodetic
      data for the rupture process of the 1995 Kobe earthquake, J. Phys. Earth, 44, 437-454, 1996.

      Koketsu, K., and S. Sekine, Pseudo-bending method for three-dimensional seismic ray tracing in a spherical earth with discontinuities,
      Geophys. J. Int., 132, 339-346, 1998.

      Koketsu, K. and S. Higashi, Three-dimensional topography of the sediment/basement interface in the Tokyo metropolitan area, central
      Japan, Bull. Seismol. Soc. Am., 82, 2328-2349, 1992.

      Koketsu, K. and M. Kikuchi, Propagation of seismic ground motion in the Kanto basin, Japan, Science, 288, No.19, 1237-1239, 2000.

      Koketsu, K. and T. Furumura, Imaging earthquake fault rupture and simulating seismic ground motion, Leading Edge, 18, No.12,
      1414-1416, 1999.