Meteotsunamis Occurring Along the Southwest Coast of South America During an Intense Storm
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In this paper, we report meteotsunamis occurring along the Chilean and Peruvian coasts. These atmospherically induced tsunami-like oscillations were instrumentally recorded during an intense storm that affected central Chile on August 8th, 2015. The storm was characterized by strong winds, a locally unprecedented atmospheric low pressure and intense sea-level oscillations which caused six casualties and severe damage to infrastructure along ~500 km of coastline. The meteotsunamis are analyzed on both regional and local scales. On the regional scale, the temporal behavior and spatial behavior were discussed from the analysis of various tide gauges covering roughly 3000 km of the southwest coast of South America, between Callao, in central Peru, and Lebu, in southern Chile. Surprisingly, the phenomenon was recorded in the majority of the tide gauges in this vast region. On the area constrained by the storm region, a more detailed analysis is performed. We confirm the atmospheric origin of these intense sea-level oscillations by further analyzing meteorological records of air pressure and wind. An attempt to explain local (shelf and harbor) resonant mechanisms is achieved by means of wavelet analysis, while Greenspan and Proudman resonance mechanisms are superficially analyzed. Our results indicate that large meteotsunamis can occur along the west coast of South America and, when combined with other meteooceanographic conditions, may cause damage levels comparable to those resulting from Mw >8 earthquake generated tsunamis.
KeywordsTsunami wavelet analysis storm of August 8th 2015 in central Chile
The authors would like to thank the collaboration of the Hydrographic and Oceanographic Service of the Chilean Navy (SHOA) for providing the sea-level records at 5 tidal stations. M. Carvajal thanks the Millennium Nucleus for the Earthquake cycle along subduction zones (CYCLO), Chile, and Dr. Samuel Hormazábal (PUCV) for his advice and encouragement on the use of time–frequency analysis techniques. P. Winckler would like to thank CONICYT (Chile) through its grant FONDECYT 11150003. I. Sepúlveda thanks Fulbright and CONICYT for financial assistance in the form of studentships. We thank the following institutions for providing meteorological data: Fondo de Desarrollo Disciplinario de Medio Ambiente-Facultad de Ingeniería (UPLA), Laboratorio de Meteorología-Instituto de Geografía (PUCV), Estación Costera de Investigaciones Marinas (PUC), Estación Montemar-Facultad de Ciencias del Mar y de Recursos Naturales (UV), Secretaría Regional Ministerial de Medio Ambiente de Valparaíso (MMA), SOPRAVAL, and AGROSUPER. Finally, we would like to deeply thank Alexander Rabinovich, Jadranka Sepic, and two anonymous reviewers for providing useful comments and suggestions that greatly improved the manuscript.
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