Seafloor Seismic Noise at Central Eastern Mediterranean Sites

Abstract

The Mediterranean region is densely populated, and many social and industrial activities take place on its coasts. As expected for a region of recent geological evolution, it is an area highly exposed to natural hazards such as seismicity and volcanic eruptions (e.g., Le Pichon and Angelier, 1979; Mazzoli and Helman, 1994). Near‐shore and offshore geophysical monitoring is needed to ensure rapid warning in the coastal areas and to mitigate the effects of natural disasters. There is a lack of seismological stations in the offshore areas and a need to integrate land networks with permanent seafloor seismometers. An international endeavor has taken place at global scale to establish permanent underwater networks (e.g., OOI in USA, NEPTUNE in Canada, and DONET in Japan; Favali et al. , 2010). In Europe, with European Multidisciplinary Seafloor and water‐column Observatory (EMSO, http://www.emso-eu.org; Favali and Beranzoli, 2009; Person et al. , 2014) there is an effort to establish a permanent underwater infrastructure for continuous multiparametric monitoring at sites placed on the European continental margin. GEOSTAR‐class observatories have already operated temporarily at some of the EMSO sites (Favali et al. , 2006a,b, 2011, 2013). These observatories can operate from shallow waters to deep sea, down to 4000 meter water depth, and simultaneously monitor a broad spectrum of geophysical and environmental processes. They, if cabled, can transmit data in real time that can be integrated with data from on‐land networks (Favali et al. , 2006b, 2011, 2013). In this work, we focus on the seismic signals acquired by GEOSTAR‐class seafloor observatories in four sites of the Central Eastern Mediterranean area that are important for earthquake and volcanic hazard assessments: the western Ionian and the southern Tyrrhenian Seas (Fig. 1a); the Marmara Sea and the Gulf of Corinth (Fig. 1b). These sites are …