César R. Ranero

Institut de Ciències del Mar (CSIC-ICM)

A new study led by the Institut de Ciències del Mar (CSIC) and ICREA has revealed the location of the boundary between the European and African tectonic plates in the Alboran Sea. The work also evaluates its potential capacity to produce large earthquakes that could trigger devastating tsunamis. The work defines for the first time the complex geometry of this active faults system and demonstrates that the system has absorbed most of the deformation from plate collision in this region during the last 5 million years.

Although the geological structure of the Alboran Sea subsurface has been extensively studied since the 1970s, until now the data were not sufficiently precise to understand the tectonics of the area.

However, using modern methodologies has made it possible to characterize in detail a system of active faults that extends over 300 kilometers long and is now considered the most important, in terms of deformation accumulation, in the Iberian Peninsula. Until now, it was unknown whether the Alboran Sea had large active faults, as well as the exact location of the tectonic boundary where the European and African plates collide. This knowledge is key to reassess the seismic and tsunami risk to which the coastal areas of the western Mediterranean are exposed.

In another study by the same group analyse the tsunamigenic potential of this plate boundary and suggest that this may be greater than previously thought. Most previous studies on seismic and tsunami risk did not correctly consider these large faults due to lack of data, so the risk had been underestimated. These new studies are a first appraisal of the seismic and tsunami potential of these large faults, which until now were almost completely unknown and must be thoroughly evaluated in future studies.