Effects of basin parameters on the spatial variation of characteristics of basin generated Rayleigh waves

摘要

Abstract This paper presents the effects of shape of interface between the sediment and basement rock (SISB), basin-shape-ratio, impedance contrast, sediment-damping and angle of incidence of body waves on the characteristics of basin generated Rayleigh (BGR) waves and associated spatial variations of average spectral amplification (ASA), differential ground motion (DGM) and average aggravation factor (AAF) in the considered 2D basin models. The seismic responses of various basin models were simulated using recently developed viscoelastic P-SV wave fourth-order spatial accurate staggered-grid finite-difference algorithm. It is inferred that the SISB has a major impact on the characteristics of the BGR-waves in basin. The obtained largest and least ASA, DGM and AAF were in the basins with SISB as triangular and trapezoidal, respectively. An increase of ASA, AAF and DGM were obtained with an increase of impedance contrast, sediment quality factor, basin shape-ratio and angle of incidence of body wave. It is also inferred that the generated Rayleigh wave in the rocky area in case of plane wave front with inclination 45° and thereafter their transmission in the basin is responsible for the unexpected AAF of the order of 4.7 in the circular basin.