Tsunami generation potential of a strike‑slip fault tip in the westernmost Mediterranean

Abstract

This study was supported by the Spanish projects DAMAGE (CGL2016-80687-R AEI/FEDER), FAUCES (CTM2015-65461-C2-1-R), RNM148, B-RNM-301-UGR18 and AGORA P18-RT-3275 Junta de Andalucia. The authors appreciate the IHS-Kingdom educational license. Research partially funded by the Programa Operativo FEDER Andalucia 2014-2020, call made by the University of Jaen 2018. The ICM-CSIC authors acknowledge Severo Ochoa funding from the Spanish government through the "Severo Ochoa Centre of Excellence" accreditation (CEX2019-000928-S). ; Tsunamis are triggered by sudden seafloor displacements, and usually originate from seismic activity at faults. Nevertheless, strike-slip faults are usually disregarded as major triggers, as they are thought to be capable of generating only moderate seafloor deformation; accordingly, the tsunamigenic potential of the vertical throw at the tips of strike-slip faults is not thought to be significant. We found the active dextral NW–SE Averroes Fault in the central Alboran Sea (westernmost Mediterranean) has a historical vertical throw of up to 5.4 m at its northwestern tip corresponding to an earthquake of Mw 7.0. We modelled the tsunamigenic potential of this seafloor deformation by Tsunami-HySEA software using the Coulomb 3.3 code. Waves propagating on two main branches reach highly populated sectors of the Iberian coast with maximum arrival heights of 6 m within 21 and 35 min, which is too quick for current early-warning systems to operate successfully. These findings suggest that the tsunamigenic potential of strike-slip faults is more important than previously thought, and should be taken into account for the re-evaluation of tsunami early-warning systems. ; Spanish project DAMAGE CGL2016-80687-R ; Spanish project FAUCES CTM2015-65461-C2-1-R ; AGORA P18-RT-3275 ; Programa Operativo FEDER Andalucia 2014-2020 ; University of Jaen ; Spanish government through the "Severo Ochoa Centre of Excellence" accreditation CEX2019-000928-S RNM148 B-RNM-301-UGR18