On the complexity of seismic waves trapped in non-flat geologic features

Abstract

Most earthquake engineering and seismological models make the sweeping assumption that the world is flat. The ground surface topography, however, has been repeatedly shown to strongly affect the amplitude, frequency, duration and damage induced by earthquake shaking, effects mostly ignored in earthquake simulations and engineering design. In this talk, I will show a collection of examples that highlight the effects of topography on seismic ground shaking, and I will point out what these results suggest in the context of the current state-of-earthquake engineering practice. Examples will range from semi-analytical solutions of wave propagation in infinite wedge to three-dimensional numerical simulations of topography effects using digital elevation map-generated models and layered geologic features. I will conclude by demonstrating that 'topography' effects vary strongly with the stratigraphy and inelastic behavior of the underlying geologic materials, and thus cannot be accurately predicted by studying the effects of ground surface geometry alone.

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