In general, topographyincreases the amplitude of shaking at mountains tops and ridges, whereas valleys usually have reduced ground motion, as has been observed in both records from past earthquakes and numerical simulations.However, the effects of realistic topography on ground motion have not been clearly characterized in numerical simulations, especially the seismic response of the true ground surface.
Numericalsimulations show that seismic shaking in mountainous areas is strongly affected by topography and source frequency domain. The amplification of ground motion mainly occurs at the tops of hills and ridgeswhilst the valleys and flat-topped hills experience lower levels of ground shaking,
We demonstrate that topographic variations can change peak ground acceleration (PGA) values by +/- 50% inmountainous areas, and the relative change in PGA between a valley and a ridge can be as high as a factor of 2 compared to a flat surface response. This suggests that high resolution, realistic topographicfeatures should be taken into account in seismic hazard analysis, especially for densely populated mountainous areas.
Several numerical studies have indicated that structures located at the tops ofhills, ridges, and canyons suffer more intense damage than structures situated at the base of hills.
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Lee, Chen, Liu (2008) used the...