Simulation of broadband seismic ground motions at dam canyons by using a deterministic numerical approach

• The spectral element method is used to generate broadband ground motions (0.1–8 Hz).
• The earthquake source, propagation path, and local site effects are all simulated.
• The variation of ground motions along dam-canyon during earthquakes is investigated.

As a deterministic numerical approach for simulation of earthquake ground motions, the spectral element method (SEM) is applied to generate a broadband acceleration array for dam-canyons instead of the traditional empirical or stochastic methods. Specifically, the SEM analysis model with an extra fine mesh is used for the Pacoima Canyon to simulate the entire path starting from earthquake source rupture via the propagation medium to the local site. The source and the 3D earth model (velocity structure) are validated through the modeling of the Newhall earthquake on 28 October 2012 at a frequency of up to 8 Hz. Subsequently, the San Fernando earthquake records on 13 January 2001 are further used to study the effects of propagation path in simulation. Finally, the spatially varying ground motions at the Pacoima Canyon are obtained for different source mechanisms. The results show that the source mechanism and the local site topography significantly affect the distribution of the peak accelerations along the canyon.

Simulation of broadband ground motions along the Pacoima dam-canyon during the Newhall earthquake on 28 October 2012.Figure optionsDownload as PowerPoint slide