Seismic wave amplification by topographic features: A parametric study

Abstract

Despite the ever increasing adoption of wave motion simulations for assessing seismic hazard, most assessment/simulations are still based on a flat surface earth model. The purpose of this paper is to quantify the effect of topographic irregularities on the ground motion and local site response by means of parametric investigations in the frequency-domain of typical two-dimensional features.To this end, we deploy best-practice tools for simulating seismic events in arbitrarily heterogeneous formations; these include: a forward wave simulator based on a hybrid formulation encompassing perfectly-matched-layers (PMLs); unstructured spectral elements for spatial discretization; and the Domain-Reduction-Method that permits placement of the seismic source within the computational domain, thus allowing consideration of realistic seismic scenarios.Of particular interest to this development is the study of the effects that various idealized topographic features have on the surface motion when compared against the response that is based on a flat-surface assumption. We report the results of parametric studies for various parameters, which show motion amplification that depends, as expected, on the relation between the topographic feature's characteristics and the dominant wavelength. More interestingly, we also report motion de-amplification patterns.

Seismic and geologic controls on spatial clustering of landslides in three large earthquakes

“…S17). Several authors have shown that ridge sharpness promotes topographic amplification (Maufroy et al, 2015;Rai et al, 2016). The landslide position would thus reflect the expression of strong ground motion in the uppermost part of the slope, which can be explained by complex interactions of various seismic waves with both topography and lithology.…”

“…Numerical simulations of ground shaking in complex topographies predict that seismic waves are actually amplified around ridge crests (e.g. Boore, 1973;Massa et al, 2014;Poursartip et al, 2017). Both seismic noise analysis and strong motion records confirm that stronger shaking often occurs at topographic highs (Chávez-García et al, 1996;Durante et al, 2017;Hartzell et al, 2014;Massa et al, 2010).…”

Analysis of overburden layer thickness influence on dynamic response of concrete face rock-fill dam

“…The static and dynamic parameters of the dam are shown in Table 2 and Table 3, in which # 1 is the major rock-fill zone and # 2 is the minor rock-fill zone, which are obtained by experimental results [22,23]. The contact parameters are presented in Table 4, where #3 is the contact surface between the panel and the dam, and #4 is the contact surface between the cut-off wall and the cover [24]. To highlight the single factor of the overburden thickness, homogeneous sand was selected as the overburden material, with the following mechanical parameters: natural dry density ( ) of 2.2 g•cm −3 , deformation modulus ( ) of 50 MPa, and friction angle ( ) of 38°.…”

3D time‐domain nonlinear analysis of soil‐structure systems subjected to obliquely incident SV waves in layered soil media

“…Huang et al [20,21] analyzed the impacts of incident angles on the seismic behavior of the long-lined tunnel buried in an elastic half-space. Poursatip et al [22,23] numerically studied the effects of topographic irregularities on the ground motion and local site response under obliquely incident P and SV waves in the frequency domain and elastic half-space. As seen, most prior studies either simplified the soil media as a uniformly elastic half-space when conducting numerical simulations, or analytically solved the problem in the frequency domain to account for the layered condition.…”