[S02-P] Poster

[S02-P-16] A physical seismic modeling study of multi-azimuth seismic refraction for a horizontal transverse isotropic medium

^○Young-Fo Chang¹, Cheng-Wei Tseng², Jia-Wei Liu¹, Chao-Ming Lin³ (1.National Chung Cheng University, Taiwan, 2.Industrial Technology Research Institute, Taiwan, 3.Hsiuping Institute of Technology, Taiwan)

In order to investigate the characteristics of anisotropic strata, a multi-azimuth seismic refraction technique is proposed in this study. To simplify the problem, a two-layer (isotropy-horizontal transverse isotropy (HTI)) model is considered. A new travel time equation of the refracted P-wave propagation in the isotropy-HTI medium is derived, which is the function of the phase and group velocities of the HTI medium. The head wave velocity measured in the physical model experiment is the group velocity. The isotropic intercept time equation of a refraction wave can be directly used to estimate the thickness of the top (isotropic) layer of an isotropy-HTI medium, because the contrast between the phase and group velocities of the HTI medium is seldom greater than 10 percent in the earth. In addition, under an assumption, the contrast between the phase and group velocities of an anisotropic medium is small, the approximated travel time equation of a refraction wave is obtained. This equation is only dependent on the group velocity of the HTI medium. The elastic constants A11, A13 and A33 and the Thomsen anisotropic parameter (Epsilon) of the HTI medium can be estimated using the multi-azimuth seismic refraction technique.