중남미

A large seismic gap lies along northern Chile and could potentially trigger a M w ~ 8.8–9.0 megathrust earthquake as pointed out in several studies. The April 1, 2014, Pisagua earthquake broke the middle segment of the megathrust. Some slip models suggest that it ruptured mainly from a depth of 30 to 55 km along dip and over 180 km in length, reaching a magnitude M w 8.1–8.2. The northern and southern segments are still unbroken; thus, there is still a large area that could generate a M w > 8.5 earthquake with a strong tsunami. To better understand the effects of source parameters on the impact of a tsunami in the near field, as a case study, we characterize earthquake size for a hypothetical and great seismic event, M w 9.0, in northern Chile. On the basis of physical earthquake source models, we generate stochastic k −2 finite fault slips taking into account the non-planar geometry of the megathrust in northern Chile. We analyze a series of random slip models and compute vertical co-seismic static displacements by adding up the displacement field from all point sources distributed over a regular grid mesh on the fault. Under the assumption of passive generation, the tsunami numerical model computes the runup along the shore.