Simulation of Tsunami Inundation in Central Peru from Future Megathrust Earthquake Scenarios

抄録

We estimated, from twelve scenarios of potential megathrust earthquakes, the tsunami impact on the Lima-Callao region in Central Peru. In addition, we conducted hazard mapping using the local envelope of the maximum inundation simulated in these scenarios. The deterministic approach is supported by the decades of geodetic measurements in this area that characterize the interseismic strain build up since historical megathrust earthquakes. The earthquake scenarios for simulation proposed in [1] introduce spatially correlated short-wavelength slip heterogeneities to a first slip model in [2] calculated from the interseismic coupling (ISC) distribution in Central Peru. The ISC was derived from GPS monitoring data as well as from historical earthquake information. The results of strong ground motion simulations in [1] reported that the slip scenario with the deepest average peak values along the strike (M_w=8.86) generates the largest PGA in the Lima-Callao area. In this study, we found from tsunami simulation results that the slip model with the largest peak slip at a shallow depth (M_w=8.87) yielded the highest tsunami inundation. Such differences in maximum scenarios for peak ground acceleration and tsunami height reveal the importance of a comprehensive assessment of earthquake and tsunami hazards in order to provide plausible worst-case scenarios for disaster risk management and education.