Tsunami Generation Potential of a Strike-slip Fault Tip in the Westernmost Mediterranean

Abstract

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 justify the re-evaluation of tsunami early-warning systems worldwide.

Coastal Environmental Impact of Geohazards in the Area of the Habibas Islands (Western Algeria, Alboran): Insights from GIS-Analysis and Remote Sensing

“…Moreover, seismites have as well been evidenced in western Oranie and the large distribution of the observed deformations within western Oranie (100 km of coastline) suggests a strong source of energy [29], [52]. Finally, the 2016 Alboran seismic sequence with the first shock of magnitude reminds the potential for strong earthquakes in the region with a well-demonstrated threat for tsunami waves reaching the western coast of Algeria not only for thrusting events but for strike-slipping motions as well [16], [53].…”

Simulation of tsunami induced by a submarine landslide in a glaciomarine margin: the case of Storfjorden LS-1 (southwestern Svalbard Islands)

“…It is widely known that how a tsunami wave propagates is highly dependent on the morphology of the seafloor (Urlaub et al, 2013;Estrada et al, 2021). The model shows that tsunami waves propagate elliptically with respect to the northeast-southwest elongated seafloor shape of the landslide relief.…”

“…This new dipole is created when the faster sliding mass reaches the slower one and both masses merge producing a significant impact in the available displaced sediment thickness (100 m) of the distal moving mass. The increase in thickness would contribute to increasing the pressure in the water column, causing the uplift in the water surface and the enhancement of the tsunami waves (Ramadan et al, 2018;Ercilla et al, 2021). Thus, our study demonstrates that a proper understanding of landslide dynamics at their initial stages (or first motion) and of their deformation during the run-out is a crucial requirement for understanding the characteristics of the initial tsunami waves and the effects that those characteristics have on their evolution.…”

“…landslides (generating single or multiple trough and crest pairs) versus faults (generating a single or crest wave) (e.g. Macías et al, 2015;Ercilla et al, 2021;Estrada et al, 2021;Bécel et al, 2017).…”

“…The Storfjorden LS-1 modelling has demonstrated that the shelf seafloor morphology is a decisive factor: it influences the propagation velocity of the tsunami waves, the variations in wave amplitude (shoaling effect) and the impact of coastal arrivals (Iglesias et al, 2012;Estrada et al, 2021;Salaree and Okal, 2020).…”