Active tectonics in the Ionian Sea realm: Subduction or collision?

The region spanning across the Ionian Sea margins in the Mediterranean is geologically complex and comparatively little evaluated, due to limited available seismic data. The poorly understood tectonic structure is however related to seismic hazard that has struck surrounding countries with devastating results in historical time.

The region contains large fault systems that extend on and offshore and are associated with dramatic lateral changes in deformation rates. However, the kinematics and activity of the main faults are poorly defined and the system are inadequately mapped.

Current knowledge we can not differentiate whether fault systems are part of a mega-thrust subduction plate boundary, or they are located above on an overriding plate, or are part of a different tectonic system, let alone we can precisely define the location, geometry and extent of plate boundary faults.

We have collected new seismic data (1.5 to 5 km long streamer) and reprocessed existing seismic data (4.5 km long streamer data) along the Ionian Sea realm during the last 10 years to study and map those system. Recently, we have been provided with industry-quality (10.5 km long streamer) lines to study remaining regions of the margins and deep basins of the region.

Our new data set provides an extensive coverage, and our new seismic images document abundant deformation that can not be easily explained by existing models of subduction-zone type of deformation, and we propose a model in which the current tectonic activity is the result of the embryonic collision process between Africa and Europe, and where the current dominant geodynamic driving forces are not longer related to slabs subducting under the continent that were previously controlling the evolution of the Mediterranean Realm.