Simulation of the Seismic Response of Sedimentary Basins with Vertical Constant-Gradient Velocity for Incident <Emphasis Type="Italic">SH</Emphasis> Waves |
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| Authors: | Email author" target="_blank">F?LuzónEmail author L?Ramírez F J?Sánchez-Sesma A?Posadas |
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| Institution: | (1) Departamento de Física Aplicada, Universidad de Almería, Cañada de San Urbano s/n, 04120 Almería, Spain;(2) Instituto Andaluz de Geofísica y, Prevención de Desastres, Sísmicos;(3) Instituto de Ingeniería, Universidad Nacional Autónoma de México, Cd. Universitaria, Coyoacán, 04510 México D.F, México |
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| Abstract: | The simulation of the seismic response of heterogeneous sedimentary basins under incident plane waves is computed using the Indirect Boundary Element Method (IBEM). To deal with these kinds of basins we used approximate analytical expressions for the two-dimensional Green s functions of a medium with constant-gradient wave propagation velocity. On the other hand, for the homogeneous half space underlying the sedimentary basin, the full space Greens functions were used. The response of semi-circular heterogeneous basins under incident SH waves is explored by means of the displacements in the frequency-space diagrams and synthetic seismograms. Moreover, we compared these results with those obtained for other homogeneous semi-circular models. The principal differences among them are pointed out. This simulation provided interesting results that displayed a complex amplification pattern in a rich spectrum of frequencies and locations. The maximum amplitudes levels were found around the edges of the heterogeneous sedimentary basins. In time domain some features characterize the seismic response of the basin which include enhanced generation and trapping of surface waves inside the sediments, and the reduced emission of seismic energy to the hard rock. In the heterogeneous models the lateral reflections of surface waves greatly influence the total displacements at the free surface in comparison with the homogeneous models where the displacements have a shared influence among both vertical and lateral reflections. |
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| Keywords: | Boundary element method Green s function" target="_blank">gif" alt="rsquo" align="BASELINE" BORDER="0">s function vertical heterogeneity sedimentary basins strong ground motion seismology |
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