Analysis of geodetic interseismic coupling models to estimate tsunami inundation and runup: a study case of Maule seismic gap, Chile

Tuesday, 15 December 2015
Poster Hall (Moscone South)
Juan F. González-Carrasco1,2, Gabriel Gonzalez1,2, Rafael Aránguiz2,3, Patricio Andres Catalan2,4, Rodrigo Cienfuegos2,5, Alejandro Urrutia2,5 and Mahesh Narayan Shrivastava2,6, (1)Universidad Católica del Norte, Departamento de Ciencias Geológicas, Antofagasta, Chile, (2)National Research Center for Integrated Disaster Management (RCINDIM/CIGIDEN), Santiago, Chile, (3)Universidad Católica de la Santísima Concepción, Department of Civil Engineering, Concepción, Chile, (4)Federico Santa María Technical University, Departamento de Obras Civiles, Valparaiso, Chile, (5)Pontifical Catholic University of Chile, Hydraulic and Environmental Engineering, Santiago, Chile, (6)Universidad Católica del Norte, Department of Geological Sciences, Antofagasta, Chile
Tsunami inundation maps are a powerful tool to design evacuation plans of coastal communities, additionally can be used as a guide to territorial planning and assessment of structural damages in port facilities and critical infrastructure (Borrero et al., 2003; Barberopoulou et al., 2011; Power et al., 2012; Mueller et al., 2015). The accuracy of inundation estimation is highly correlated with tsunami initial conditions, e.g. seafloor vertical deformation, displaced water volume and potential energy (Bolshakova et al., 2011). Usually, the initial conditions are estimated using homogeneous rupture models based in historical worst-case scenario. However tsunamigenic events occurred in central Chilean continental margin showed a heterogeneous slip distribution of source with patches of high slip, correlated with fully-coupled interseismic zones (Moreno et al., 2012).

The main objective of this work is to evaluate the predictive capacity of interseismic coupling models based on geodetic data comparing them with homogeneous fault slip model constructed using scaling laws (Blaser et al., 2010) to estimate inundation and runup in coastal areas. To test our hypothesis we select a seismic gap of Maule, where occurred the last large tsunamigenic earthquake in the chilean subduction zone, using the interseismic coupling models (ISC) proposed by Moreno et al., 2011 and Métois et al., 2013. We generate a slip deficit distribution to build a tsunami source supported by geological information such as slab depth (Hayes et al., 2012), strike, rake and dip (Dziewonski et al., 1981; Ekström et al., 2012) to model tsunami generation, propagation and shoreline impact using Neowave 2D (Yamazaki et al., 2009). We compare the tsunami scenario of Mw 8.8, Maule based in coseismic slip distribution proposed by Moreno et al., 2012 with homogeneous and heterogeneous models to identify the accuracy of our results with sea level time series and regional runup data (Figure 1). The estimation of tsunami source using ISC model can be useful to improve the analysis of tsunami threat, based in more realistic slip distribution.