Probabilistic tsunami hazard in the Mediterranean Sea

Abstract

[1] Estimating the occurrence probability of natural disasters is critical for setting construction standards and, more generally, prioritizing risk mitigation efforts. Tsunami hazard in the Mediterranean region has traditionally been estimated by considering so-called "most credible" scenarios of tsunami impact for limited geographical regions, but little attention has been paid to the probability of any given scenario. We present here the first probabilistic estimate of earthquake-generated tsunami hazard for the entire Mediterranean Sea. We estimate the annual probability of exceeding a given tsunami amplitude at any coastal location in the region by applying a Monte Carlo based technique. Earthquake activity rates are estimated from the observed seismicity, and tsunami impact is derived from deterministic tsunami wave propagation scenarios. The highest hazard is in the eastern Mediterranean owing to earthquakes along the Hellenic Arc, but most of the Mediterranean coastline is prone to tsunami impact. Our method allows us to identify the main sources of tsunami hazard at any given location and to investigate the potential for issuing timely tsunami warnings. We find that the probability of a tsunami wave exceeding 1 m somewhere in the Mediterranean in the next 30 years is close to 100%. This underlines the urgent need for a tsunami warning system in the region.

Tsunami hazard assessment in El Salvador, Central America, from seismic sources through flooding numerical models.

“…Tsunami hazard assessment can be approached by both probabilistic (PTHA, Probabilistic Tsunami Hazard Assessment) and deterministic methods. When PTHA is performed, it is often considered as an extension of probabilistic seismic hazard assessment (PSHA) (Annaka et al, 2007;Burbidge et al, 2008;González et al, 2009;Grezio et al, 2010;Sørensen et al, 2012;Power et al, 2012), obtaining seismic return periods for potential tsunamigenic earthquakes and incorporating the aleatory uncertainties on the fault and tidal level parameters.…”

Synthetic tsunami waveform catalogs with kinematic constraints

“…For the case of the Azores-Gibraltar plate boundary, rigidity has been differently evaluated in a significant way: Johnston (1996) uses µ = 6.5×10 10 Pa. Since µ = ρ V 2 S , Stich et al (2007) propose a slightly higher value µ = 7.0 × 10 10 Pa. Heinrich et al (1994) assume a lower value, µ = 4×10 10 Pa. The choice of this parameter will influence the result in terms of tsunami hazard.…”

“…In situations where the effects of smaller tsunami events are also important (e.g. interaction with harbours or other coastal structures), probabilistic hazard assessments can give a better insight into expected amplitudes and recurrence times (Geist and Parsons, 2006;Power et al, 2007;González et al, 2009;Sørensen et al, 2012;Omira et al, 2015).…”

Implementation and Challenges of the Tsunami Warning System in the Western Mediterranean

“…Because this context is rather complex along the North African margin, the choice was made to draw a simplified fault system discretized into unit sources corresponding to the major structural trends of the area. The unit source database used a comprehensive bibliography including seismicity catalogs, focal mechanisms, seismotectonic works (e.g., PONDRELLI et al 2004;Á lvarez Gómez et al 2011), seismic reflection profiles (e.g., DÉVERCHÈRE et al 2005), bathy/topo data, satellite imagery, etc., to propose an exhaustive geodynamic framework (extending beyond works such as LORITO et al 2008or SORENSEN et al 2012. Fault traces shown on Fig.…”