Surface Wave Research Paper

Torsional Surface Wave in a Prestressed Anisotropic Intermediate Poroelastic Layer of Varying Heterogeneities

Rajneesh Kakar*1a and Shikha Kakar2b

1Faculty of Engineering & Technology, GNA University, Hargobindgarh, Phagwara

2Department of Electronics, SBBS University, Padhiana, India

Abstract: This paper considers the existence of torsional surface wave in a heterogeneous initially stressed vertical fluid saturated anisotropic layer sandwiched between inhomogeneous and homogeneous porous half-spaces. It has been considered that the mass density and the rigidity of upper half-space and intermediate layer are space dependent. The proposed model is solved to obtain different dispersion relations for the torsional surface wave in a poroelastic

The propagation of torsional surface waves in the fluid saturated porous layered media is useful to understand fluid dynamics, soil dynamics, earthquake disaster prevention, oil exploration and groundwater prospecting. Recent conceptual and innovative developments disclose that the physical properties of the torsional surface waves in fluid saturated poroelastic media are entirely different from viscoelastic and elastic media. Due to heterogeneities in the crust of the earth, the study of torsional wave becomes important to understand earthquake disaster. Several studies have been carried out to explain the nature of torsional wave in isotropic homogeneous and heterogeneous media but less literature is available to show the effect of anisotropy of the medium on the torsional wave propagation. So, in order to understand the accurate seismic pattern it becomes important and necessary to consider anisotropy and different heterogeneities of the elastic material

The porous layer of earth has amazing properties such as heterogeneity, anisotropy, and initial stress. Generally the pores of the porous rock may contain gas or oil or water and layer may be saturated either with gas or any one of these. The fluid saturated porous medium affects the torsional surface waves and it is a much root of attenuation. A large number of problems in seismology can be explained by representing earth as a fluid saturated porous layered structure with mechanical properties and finite thickness. In fact the study of torsional waves in heterogeneous fluid saturated porous layered media has been a point of interest to geophysicists until recently. In order to understand the underground response of seismic wave propagation toward material properties and initial stresses of the Earth, researchers and seismologists generally prefer porous rock models with various heterogeneities in semi-infinite domains. These initial stresses influence elastic wave propagation more prominently. Physical properties of the torsional waves refracted across boundaries of the Earth, such as phase velocity, energy loss, and particle motion, vary with heterogeneities present in the media. The Earth has finite dimensions; the effects of boundaries of the Earth on the generated elastic waves cannot be ignored. This property of Earth motivates us to