Great earthquakes and the possibility to generate destructive tsunamis are geohazards of key societal concern, as they may impact world economies, disturb submarine structures and affect coastal populations with the associated risk for local populations. We still have in our mind catastrophic episodes, such as the giant events of the Sumatra earthquake and tsunami in 2004 in the Indian Ocean of magnitude (Mw) 8.7, and the Tohoku-Oki earthquake and tsunami in 2011 in the north west of Japan, of magnitude (Mw) 9-9.1. Nevertheless, seismic events of moderate to large magnitude (Mw 6-7.3) in areas of low to moderate tectonic deformation, and with long recurrence intervals, such as the Alboran Sea in the Western Mediterranean, might also have a significant effect. The Alboran Sea is a Neogene basin locates between Iberian and Nubia plates. Miocene deformation related to roll-back of Tethys oceanic lithosphere was followed by a compressive regime, which lasted from Pliocene until today, including the development of strike-slip and thrust faults. Seismicity is characaterised by earthquakes of low to moderate magnitude, although large historical (MSK VIII-X) and instrumental earthqaukes also ocurred in the region. On the 25th January 2016, a Mw 6.4 earthquake hit the area offshore the city of Al-Hoceima on the Moroccan coast. THis is the largest event ever recorded in the Alboran Sea. The source of the 2016 seismic event is the Al-Idrissi Fault System (AIFS), a 100-km-long crustal-scale boundary with left-lateral strike-slip displacement. The occurrence of the Mw 6.4 earthquake supports that the AIFS is currently growing through propagation and linkage of its segments on the basis of our recent published article in Nature Communications(Gràcia et al., 2019). In the frame of the STRENGTH project, we aim to: 1) Map the earthquake rupture of the 2016, as well the releasing and restraining bends along the Al-Idrissi Fault System (AIFS) segments and related faults using the vehicle HOV Ariane (IFREMER, Fr) that includes microbathymetry using an Autonomous Underwater Vehicle (AUV) and visual ground-truthing using a Remotely Operated Vehicle (ROV); 2) Characterize the crustal domains across the AIFS, the West Alboran and North African domains using Ocean Bottim Seismographs (OBS) in collaboration with GEOMAR (Kiel, Germany); 3) Sample Quaternary stratigraphic sequences across tectonic domains using the extra-long CALYPSO piston core onboard the RV Marion Dufresne (IFREMER, Fr). We will also use existing MEBo drilling cores (MARUM, Germany) recently acquired to complement the seismo-stratigraphy; 4) Perform analogue and numerical of the NS Faults to understand their growth and the potential evolution; 5) Accomplish tsunami models (Hy-Sea, INGV-It) of the largest and potentially tsunamigenic structures of teh Alboran Sea, such as the AIFS, Alboran Ridge Fault System, Carboneras Fault System and Yusuf Fault System; and 6) Quantify the seismic potential & seismic hazard of the area, on the basis of empirical relationships and numerical models (e.g. SHERIFF). The results of STRENGTH project will have national and international impact on the Marine Geosciences community. Our results in the frame of STRENGTH project will allow a significant progress by introducing and adapting new advanced techniques to obtain micro-bathymetry, seafloor images and obtaining more realistic models of seismic hazards and tsunami modelling

Presentation of Research Projects initiated in 2020 at ICM

Peer reviewed