Meteotsunamis Occurring Along the Southwest Coast of South America During an Intense Storm MATI ´ AS CARVAJAL, 1,2 MANUEL CONTRERAS-LO ´ PEZ, 3 PATRICIO WINCKLER, 4 and IGNACIO SEPU ´ LVEDA 5 Abstract—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 meteot- sunamis 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. Key words: Tsunami, wavelet analysis, storm of August 8th 2015 in central Chile. 1. Introduction The destructive effects produced by recent meteotsunamis in different coastal regions of the world highlight their importance as coastal hazards and the need for their characterization. Meteot- sunamis are typically defined as tsunami-like waves induced by atmospheric disturbances that can reach the coast with hazardous heights as a consequence of various resonant processes (Monserrat et al. 2006; Vilibic ´ et al. 2015; Pattiaratchi and Wijeratne 2015). The resonant mechanisms occur when the atmo- spheric disturbance persistently transfers energy either into local free ocean waves propagating towards the coast (Proudman 1929) or into trapped edge waves propagating along the coast (Greenspan 1956). Meteotsunamis can further be intensified near the coast through other local mechanisms such as shelf and harbor resonance (Raichlen 1966; Mon- serrat et al. 2006;S ˇ epic ´ et al. 2009; Vilibic ´ and S ˇ epic ´ 2009). Although meteotsunamis might occur anywhere in the world, most reports have been limited to the northern hemisphere. For instance, meteotsunamis have been observed along the coasts of Spain, Croatia, Japan, United States, Italy, China, the Baltic Sea, and Sri Lanka, as depicted in Fig. 1a (Pat- tiaratchi and Wijeratne 2015). Conversely, evidence for meteotsunamis in the southern hemisphere is scarce. The few confirmed cases have been reported mainly in New Zealand (Goring 2009), Australia (Pattiaratchi and Wijeratne 2014), South Africa (Okal et al. 2014), Argentina (Dragani et al. 2014), and Brazil (Candella 2009). Although recently, Vilibic ´ and S ˇ epic ´ (2017) reported tsunami-like sea-level oscillations of up to 152 cm in Bahı ´a Mansa (40.68– 1 Escuela de Ciencias del Mar, Pontificia Universidad Cato ´lica de Valparaı ´so, Valparaı ´so, Chile. E-mail: matias.carvajal.ramirez@gmail.com 2 Millennium Nucleus for the Earthquake Cycle Along Subduction Zones (CYCLO), Valparaı ´so, Chile. 3 Facultad de Ingenierı ´a y Centro de Estudios Avanzados, Universidad de Playa Ancha, Valparaı ´so, Chile. E-mail: manuel.contreras@upla.cl 4 Escuela de Ingenierı ´a Civil Ocea ´nica, Universidad de Valparaı ´so, Valparaı ´so, Chile. E-mail: patricio.winckler@uv.cl 5 School of Civil and Environmental Engineering, Cornell University, Ithaca, USA. E-mail: is328@cornell.edu Pure Appl. Geophys. Ó 2017 Springer International Publishing AG DOI 10.1007/s00024-017-1584-0 Pure and Applied Geophysics