@article {Gracia2012a, title = {{Acoustic and seismic imaging of the Adra Fault (NE Alboran Sea): in search of the source of the 1910 Adra earthquake}}, journal = {Natural Hazards and Earth System Science}, volume = {12}, number = {11}, year = {2012}, month = {nov}, pages = {3255{\textendash}3267}, publisher = {European Geosciences Union}, abstract = {Recently acquired swath-bathymetry data and high-resolution seismic reflection profiles offshore Adra (Almer{\'\i}a, Spain) reveal the surficial expression of a NW-SE trending 20 km-long fault, which we termed the Adra Fault. Seismic imaging across the structure depicts a sub-vertical fault reaching the seafloor surface and slightly dipping to the NE showing an along-axis structural variability. Our new data suggest normal displacement of the uppermost units with probably a lateral component. Radiocarbon dating of a gravity core located in the area indicates that seafloor sediments are of Holocene age, suggesting present-day tectonic activity. The NE Alboran Sea area is characterized by significant low-magnitude earthquakes and by historical records of moderate magnitude, such as the Mw Combining double low line 6.1 1910 Adra Earthquake. The location, dimension and kinematics of the Adra Fault agree with the fault solution and magnitude of the 1910 Adra Earthquake, whose moment tensor analysis indicates normal-dextral motion. The fault seismic parameters indicate that the Adra Fault is a potential source of large magnitude (Mw <= 6.5) earthquakes, which represents an unreported seismic hazard for the neighbouring coastal areas.{\textcopyright} 2013 IEEE.}, issn = {1684-9981}, doi = {10.5194/nhess-12-3255-2012}, url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-84881091009\&partnerID=tZOtx3y1 http://digital.csic.es/handle/10261/64147}, author = {Gr{\`a}cia, E. and Bartolome, R. and Lo Iacono, C. and Moreno, X. and Stich, D. and Mart{\'\i}nez-Diaz, J. J. and Bozzano, G. and Martinez-Loriente, S. and Perea, H. and Diez, S. and Masana, E. and Danobeitia, J. J. and Tello, O. and Sanz, J. L. and Carre{\~n}o, E.} } @article {Bartolome2012, title = {{Evidence for active strike-slip faulting along the Eurasia-Africa convergence zone: Implications for seismic hazard in the southwest Iberian margin}}, journal = {Geology}, volume = {40}, number = {6}, year = {2012}, month = {apr}, pages = {495{\textendash}498}, abstract = {New seismic imaging and seismotectonic data from the southwest Iberian margin, the site of the present-day boundary between the European and African plates, reveal that active strike slip is occurring along two prominent lineaments that have recently been mapped using multibeam bathymetry. Multichannel seismic and subbottom profiler images acquired across the lineaments show seafloor displacements and active faulting to depths of at least 10 km and of a minimum length of 150 km. Seismic moment tensors show predominantly WNW-ESE rightlateral strike-slip motion, i.e., oblique to the direction of plate convergence. Estimates of earthquake source depths close to the fault planes indicate upper mantle (i.e., depths of 40-60 km) seismogenesis, implying the presence of old, thick, and brittle lithosphere. The estimated fault seismic parameters indicate that the faults are capable of generating great magnitude (Mw >= 8.0) earthquakes. Such large events raise the concomitant possibility of slope failures that have the potential to trigger tsunamis. Consequently, our findings identify an unreported earthquake and tsunami hazard for the Iberian and north African coastal areas. {\textcopyright} 2012 Geological Society of America.}, issn = {0091-7613}, doi = {10.1130/G33107.1}, url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-84862119131\&partnerID=tZOtx3y1}, author = {Bartolome, R. and Gr{\`a}cia, E. and Stich, D. and Martinez-Loriente, S. and Klaeschen, D. and de Lis Mancilla, F. and Lo Iacono, C. and Danobeitia, J. J. and Zitellini, N.} } @article {LoIacono2012a, title = {{Large, deepwater slope failures: Implications for landslide-generated tsunamis}}, journal = {Geology}, volume = {40}, number = {10}, year = {2012}, month = {aug}, pages = {931{\textendash}934}, abstract = {Deepwater landslides are often underestimated as potential tsunami triggers. The North Gorringe avalanche (NGA) is a large (\~{}80 km3 and 35 km runout) newly discovered and deepwater (2900 m to 5100 m depth) mass failure located at the northern fl ank of Gorringe Bank on the southwest Iberian margin. Steep slopes and pervasive fracturing are suggested as the main preconditioning factors for the NGA, while an earthquake is the most likely trigger mechanism. Near-fi eld tsunami simulations show that a mass failure similar to the NGA could generate a wave >15 m high that would hit the south Portuguese coasts in \~{}30 min. This suggests that deepwater landslides require more attention in geo-hazard assessment models of southern Europe, as well as, at a global scale, in seismically active margins. {\textcopyright} 2012 Geological Society of America.}, issn = {0091-7613}, doi = {10.1130/G33446.1}, url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-84868693659\&partnerID=tZOtx3y1}, author = {Lo Iacono, C. and Gr{\`a}cia, E. and Zaniboni, F. and Pagnoni, G. and Tinti, S. and Bartolome, R. and Masson, D. G. and Wynn, R. B. and Lourenco, N. and Pinto de Abreu, M. and Danobeitia, J. J. and Zitellini, N.} } @article {Sallares2009, title = {{Relative contribution of temperature and salinity to ocean acoustic reflectivity}}, journal = {Geophysical Research Letters}, volume = {36}, number = {20}, year = {2009}, month = {oct}, pages = {L00D06}, abstract = {Marine seismic data display laterally coherent reflectivity from the water column that is attributed to fine-scale oceanic layering. The amplitude of the different reflections is the expression of acoustic impedance contrasts. between neighbouring water masses, and therefore water reflectivity maps the ocean{\textquoteright}s vertical sound speed and density (i.e., temperature and salinity) variations. Here we determine the relative contribution of each parameter by computing the temperature and salinity partial derivatives of sound speed and density, and using them to estimate reflection coefficients from a real oceanographic dataset. The results show that the mean contribution of density variations is 5-10\%, while 90-95\% is due to sound speed variations. On average, 80\% of reflectivity comes from temperature contrasts. Salinity contribution averages 20\%, but it is highly variable and reaches up to 40\% in regions prone to diffusive convection such as the top of the Mediterranean Undercurrent in the Gulf of Cadiz. Copyright 2009 by the American Geophysical Union.}, issn = {0094-8276}, doi = {10.1029/2009GL040187}, url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-72149084920\&partnerID=tZOtx3y1}, author = {Sallar{\`e}s, V. and Biescas, B. and Buffett, G. and Carbonell, R. and Danobeitia, J. J. and Pelegr{\'\i}, J. L.} } @article {Biescas2008, title = {{Imaging meddy finestructure using multichannel seismic reflection data}}, journal = {Geophysical Research Letters}, volume = {35}, number = {11}, year = {2008}, month = {jun}, pages = {L11609}, abstract = {This work illustrates the great potential of multichannel seismic reflection data to extract information from the finestructure of meddies with exceptional lateral resolution (10-15 m). We present seismic images of three meddies acquired in the Gulf of Cadiz (SW Iberian Peninsula), which consist of concentric reflectors forming oval shapes that sharply contrast with the background oceanic structure. The seismic images reveal the presence of different regions within the meddies that are consistent with those observed in historical temperature (T) and salinity (S) data. The core region, characterized by smooth T and S variations, is weakly reflective. The double-diffusive upper and lower boundaries and the lateral-interleaving outer edges, characterized by stronger T and S contrasts, display strong reflectivity bands. These new observations clearly show differences between layers developed at the upper and lower boundaries that can contribute to th knowledge of mixing processes and layering formation in oceans. Copyright 2008 by the American Geophysical Union.}, issn = {0094-8276}, doi = {10.1029/2008GL033971}, url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-49849096389\&partnerID=tZOtx3y1}, author = {Biescas, B. and Sallar{\`e}s, V. and Pelegr{\'\i}, J. L. and Mach{\'\i}n, F. and Carbonell, R. and Buffett, G. and Danobeitia, J. J. and Calahorrano, A.} }