BASIN EFFECTS ON SURFACE WAVE AMPLIFICATION

Abstract

For the simulation of Rayleigh wave, fourth order staggered grid wave FD program was used for both the homogeneous and basin models (Narayan and Kumar, 2014). The Gabor wavelet was used for the source excitation. The effects of basin shape ratio, impedance contrast and the shape of basin on the Rayleigh wave is analyzed. The simulation of this wave revealed the mode transformation and amplification of the Rayleigh wave at the basin-edge. The spectral amplification increased when the depth was increased at the left edge of the basin as well as in the entire basin. In case of higher frequencies the spectral amplification decreased with the increase of basin depth. The spectral amplification was found to be highest in case of triangular basin. Similarity between the elliptical model and gentle slope trapezoidal model was obtained. The increase in average spectral amplification was found to be increasing with increase in IC. The decrease in spectral amplitude while moving away from the basin edge was found due to the damping effects in the basin.