An analytical solution to the scattering of cylindrical SH waves by a partially filled semi-circular alluvial valley: near-source site effects

Abstract

The earth's surface irregularities can substantially affect seismic waves and induce amplifi cations of ground motions. This study investigates whether and how the source characteristics affect the site amplifi cation effects. An analytical model of a line source of cylindrical waves impinging on an alluvial valley is proposed to link the source and site. The analytical solution to this problem proves one aspect of the strong effect of source on site amplifi cation, i.e., the wave curvature effect. It is found that the site amplifi cation depends on the source location, especially under conditions of a small source-to-site distance. Whether the displacement is amplifi ed or reduced and the size of the amplifi cation or reduction may be determined by the location of the source. It is suggested that traditional studies of site responses, which usually ignore the source effect, should be further improved by combining the source with site effects.

Propagation of Nonplanar SH Waves Emanating from a Fault Source around a Lined Tunnel

“…There has been strict mathematical proof that the line source cylindrical waves can be reduced to plane waves for a sufficiently large source-receiver distance [16,17]. If the excitation is changed as a finite fault, however, does the same conclusion stand?…”

“…Gao and Zhang [16] provided a solution of wave functions for the cylindrical SH wave scattering induced by a symmetrical V-shaped canyon. Zhang et al [17] investigated near-source site effects based on a partially filled semicircular alluvial valley. But most earthquakes occur on the faults, i.e., the Chi-Chi earthquake (1999) resulted from the reactivation of the Chelungpu Fault [1], and major shock of Wenchuan earthquake (2008) occurred on the Beichuan-Yingxiu Fault [18].…”

A fast-multi-pole accelerated method of fundamental solutions for 2-D broadband scattering of SH waves in an infinite half space

“…In general, the calculation methods for the wave scattering include the analytical methods and numerical methods. The analytical methods are mainly referred to the wave function expansion methods [1][2][3][4][5][6][7][8]. The numerical methods include finite difference methods (FDM) [9,10], finite element methods (FEM) [11,12], boundary element methods (BEM) [13][14][15][16][17][18][19][20], and more works can be found in a review by Sanchez-Sesma et al [21] and by Manolis and Dineva [22].…”