Quasi Real-Time Tsunami Early Warning Assessment Based on Finite Fault models
Abstract. In Chile, Tsunami Early Warning relies on a precomputed set of scenarios for places near the tsunami generation zone. These scenarios are non-realistic and are computed from a uniform constant slip over the rupture surface, because of the short reaction time for the local authorities to manage the threat. Here, we present a new methodology that allows quasi-real time tsunami modelling using a finite fault model inversion to evaluate tsunami threat levels. A linear approximation at first order terms of the shallow water wave equations turns into a numerical solver that can be implemented on a programming language. As a case of study, the proposed method is applied in Chile. The results show that it is possible to obtain realistic threat levels and arrival times for the tsunami in progress. Once the finite fault is calculated, it takes a minute to produce the warning maps.
The proposal considers realistic heterogeneous and kinematic fault models of seismic sources obtained rapidly using continuous GPS, strong motion and broadband records, expanding the evaluation capabilities of Tsunami Early Warning Systems. Using directly the finite fault avoids the unrealistic model of uniform slip distribution and diminishes the uncertainty imposed by precomputed scenarios.
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