First assessment of marine soundscape alterations during the formation of a new lava delta from a sub-aerial volcanic eruption: the case of Cumbre Vieja volcano (La Palma)

Resumen

International Workshop on Geosciences in Active Areas (WGAAL), 16-20 October 2023, Arrecife-Lanzarote,Canary Islands, SpainO-021First assessment of marine soundscape alterations during the formationof a new lava delta from a sub-aerial volcanic eruption: the case ofCumbre Vieja volcano (La Palma)Jesús Alcázar-Treviño1,2, Guillermo Lara3,4, Manuel Bou3,4, Susannah Buchan5,6,7, FranciscoDomínguez-Yanes8, Eugenio Fraile-Nuez21 Departamento de Ingeniería Industrial, Escuela Superior de Ingeniería y Tecnología,Universidad de La Laguna, P.O. Box 456, 38200 La Laguna, Spain (jalcazar@ull.edu.es)2 Centro Oceanográfico de Canarias, Instituto Español de Oceanografía (IEO), ConsejoSuperior de Investigaciones Científicas (CSIC), 38180 Santa Cruz de Tenerife, Spain3 Instituto Español de Oceanografía (IEO), C.O. Murcia, C/ el Varadero 1, Lo Pagan, 30740Murcia, Spain4 Unidad Mixta de Investigación IEO (CSIC)-UPV, Tinglados Muelle Frutero, Grau de Gandia,46370 Valencia, Spain5 Centro de Estudios Avanzados en Zonas Áridas (CEAZA), Raul Bitran 1305, 1700000, LaSerena, Chile6 Center for Oceanographic Research COPAS Sur-Austral and COPAS COASTAL, Universidadde Concepción, Casilla 160-C, 4070043, Concepción, Región del Bio, Chile7 Departamento de Oceanografía, Facultad de Ciencias Naturales y Oceanográficas,Universidad de Concepción, Casilla 160-C, 4070043, Concepción, Región del Bio, Chile8 DC Servicios Ambientales, C/ Robayna, 13, 1ºI. 38003 Santa Cruz de Tenerife, SpainABSTRACTMarine soundscapes are made up of natural sounds from the geophony and the biophony and by man-made sounds fromthe anthrophony. The soundscape can reflect ecosystem state and is susceptible to drastic changes from both natural andanthropogenic events. The sub-aerial volcanic eruption at Cumbre Vieja rift at La Palma (Canary Islands) produced lava flowsthat reached the sea, forming two lava deltas that changed the geomorphology and physical- chemical seawatercharacteristics at a local scale in a marine protected area. Here we investigated acoustic recordings from sensors moored inshallow waters near these geological formations, both during and after the eruption. We computed acoustic metrics to studythe marine soundscape during the eruption, looking for candidate sounds associated with the high-temperature lava flowthat met the cooler seawater. Then, we compared these metrics with those calculated for almost a year after the eruption,exploring the geophony, anthrophony and the possible effects of these in the biophony. Our results show much higher soundlevels at low frequencies (<100 Hz) in the recordings during the eruption, even locating impulsive low-frequency sounds (<50Hz) that could be attributed to this lava-seawater contact. We also detected biological choruses and delphinid vocalizations,which could be influenced by the volcanic eruption. We encourage the continuity of these passive acoustic monitoring effortscombined with other methods to study the recovery of this protected area. Moreover, validation of sounds related to volcanicproducts reaching the sea could help to safely monitor remote areas susceptible of these drastic events.