Japan Geoscience Union Meeting 2016

Presentation information

International Session (Oral)

Symbol S (Solid Earth Sciences) » S-TT Technology & Techniques

[S-TT17] Recent Advances in Exploration Geophysics (RAEG2016)

Tue. May 24, 2016 10:45 AM - 12:15 PM A03 (APA HOTEL&RESORT TOKYO BAY MAKUHARI)

Convener:*Hitoshi Mikada(Kyoto University), Yoshihisa Iio(Disater Prevention Research Institute, Kyoto University), Yasuo Ogawa(Volcanic Fluid Research Center Tokyo Institute of Technology), Junichi Takekawa(Graduate School of Science, Kyoto University), Junzo Kasahara(University of Shizuoka, Faculty of Earth Scieces), Nobukazu Seama(Department of Planetology, Graduate School of Science, Kobe University), Tatsuya Sato(Geothermal Energy Research & Development Co., LTD.), Eiichi Asakawa(JGI, Inc.), Chair:Hitoshi Mikada(Kyoto University), Toshinori Kimura(Japan Agency for Marine-Earth Science and Technology)

11:00 AM - 11:15 AM

[STT17-08] Numerical Study for Anisotropic Influences on Elastic Wavefields Near Surface

*Rina Yoneki1, Hitoshi Mikada1, Junichi Takekawa1 (1.Graduate School of Engineering, kyoto University)

Keywords:Anisotropy, Elastic wavefiels, Numerical simulation

Anisotropic velocity analysis is important for understanding characterization of hydraulic induced fractures and near surface structure with sedimentary materials. There are many studies on seismic wave propagation in transversely isotropic and orthorhombic media (e.g., Thomsen, 1986; Alkhalifah, 2000). In most of those studies, the magnitude of anisotropy is assumed to be weak. In addition, there are few studies on seismic wavefields in quite strongly anisotropic media. Therefore, it may not be appropriate to apply their theories directly to strongly anisotropic subsurface media. It is necessary to understand the effects of the anisotropy on the behavior of seismic wave propagation in strongly anisotropic media in the seismic exploration. In this study, we investigate the influence of strong anisotropy on received seismic waveforms using three-dimensional numerical models, and verified capability of detecting subsurface anisotropy. Our numerical models contain an isotropic and an anisotropic (transversely isotropic) layer in an isotropic background subsurface. Since the difference between the two models is only the anisotropy in the vertical propagation velocity, we could observe the influence of anisotropy in the residual wavefield that is the difference in the observed wavefields of two models. The residual waveforms could be exploited to estimate both the order of anisotropy and the thickness of anisotropic layer in subsurface.