Journal of Geophysical Research: Oceans
Pablo Cortes, 1,2; Patricio A. Catalan, 1,2,3; Rafael Aranguiz, 2,4; and Giorgio Bellotti, 5
1 Departamento de Obras Civiles, Universidad Tecnica Federico Santa Marıa, Valparaıso, Chile
2 Centro Nacional de Investigacion para la Gestión Integrada de Desastres Naturales, CONICYT/FONDAP/1511007, Santiago, Chile
3 Centro Cientıfico Tecnologico de Valparaıso-CCTVal, Universidad Tecnica Federico Santa Marıa, Valparaıso, Chile
4 Department of Civil Engineering, University Catolica Ssma Concepción, Concepción, Chile
5 Department of Engineering, Roma Tre University, Rome, Italy
This work presents the analysis of long waves resonance in two of the main cities along the northern coast of Chile, Arica, and Iquique, where a large tsunamigenic potential remains despite recent earthquakes. By combining a modal analysis solving the equation of free surface oscillations, with the analysis of background spectra derived from in situ measurements, the spatial and temporal structures of the modes are recovered. Comparison with spectra from three tsunamis of different characteristics shows that the modes found have been excited by past events. Moreover, the two locations show different response patterns. Arica is more sensitive to the characteristics of the tsunami source, whereas Iquique shows a smaller dependency and similar response for different tsunami events. Results are further compared with other methodologies with good agreement. These findings are relevant in characterizing the tsunami hazard in the area, and the methodology can be further extended to other regions along the Chilean coast.