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[ES] Debido a la falta de datos, los estudios disponibles hasta ahora infravaloraban el riesgo sísmico y de tsunamis de estas grandes fallas. Ahora, un nuevo trabajo liderado por el Instituto de Ciencias del mar del CSIC demuestra que esta zona ha absorbido casi toda la deformación del choque de placas en esta región, [CAT] A causa de la manca de dades, els estudis disponibles fins ara infravaloraven el risc sísmic i de tsunamis d’aquestes grans falles. Ara, un nou treball liderat per l’Institut de Ciències del Mar del CSIC demostra que aquesta zona ha absorbit gairebé tota la deformació del xoc de plaques a aquesta regió

20 pages, 3 figures, A marine hazard is a potentially damaging event, phenomenon or activity in the marine environment that may cause loss of human life, social and economic disruption or environmental degradation. In the last 30 years, natural and human-induced hazards have caused over 1.6 million victims and the economic losses average 300 thousand million dollars per year. Marine hazards are amongst the most devastating ones. Here we present the research challenges we face as a society to achieve a safer ocean whereby human communities and the environment are better protected from the most outstanding biological, climatic and geological threats. We advocate for the implementation of a multi-hazard research strategy with emphasis on trans-disciplinary collaboration, development of improved observational infrastructures and data-sharing platforms, multi-hazard warning and management, and effective transfer of information to stakeholders and authorities to enhance impact mitigation

19 pages, 8 figures, supporting information https://doi.org/10.1029/2020JB019854.-- Data Availability Statement. The WESTMED data are archived at PANGAEA repository (https://doi.pangaea.de/10.1594/PANGAEA.921252), GEBCO bathymetry grid (https://doi.org/10.5285/a29c5465‐b138‐234d‐e053‐6c86abc040b9), and SRTM bathymetry/topography grid (https://doi.org/10.5067/MEaSUREs/SRTM/SRTMGL1.003), In continental settings, seismic failure is generally restricted to crustal depth. Crustal structure is therefore an important proxy to evaluate seismic hazard of continental fault systems. Here we present a seismic velocity model across the Gibraltar Arc System, from the Eurasian Betics Range (South Iberian margin), across offshore East Alboran and Pytheas (African margin) basins, and ending onshore in North Morocco. Our results reveal the nature and configuration of the crust supporting the coexistence of three different crustal domains: the continental crust of the Betics, the continental crust of the Pytheas Basin (south Alboran Basin) and onshore Morocco, and a distinct domain formed of magmatic arc crust under the East Alboran Basin. The magmatic arc under the East Alboran Basin is characterized by a velocity structure containing a relatively high‐velocity lower crust (~7 km/s) bounded at the top and base by reflections. The lateral extension of this crust is mapped integrating a second perpendicular wide‐angle seismic profile along the Eastern Alboran basin, together with basement samples, multibeam bathymetry, and a grid of deep‐penetrating multichannel seismic profiles. The transition between crustal domains is currently unrelated to extensional and magmatic processes that formed the basin. The abrupt transition zones between the different crustal domains support that they are bounded by crustal‐scale active fault systems that reactivate inherited structures. Seismicity in the area is constrained to upper‐middle crust depths, and most earthquakes nucleate outside of the magmatic arc domain, This work is supported by the Cluster of Excellence “The Future Ocean”, within the framework of the Excellence Initiative by the Deutsche Forschungsgemeinschaft (DFG) on behalf of the German federal and state governments. Efforts benefitted from funding of the German Science Foundation (DFG Grants GR1964/12‐1, RA 925/2‐1+2‐2, and RE 873/17‐1). The TOPOMED cruise was part of the EUROMARGINS and TOPO‐EUROPE initiatives of the EUROCORES Programme of the European Science Foundation (ESF). This study benefitted from an EU Marie Skłodowska‐Curie Individual Fellowship to L. Gómez de la Peña (H2020‐MSCA‐IF‐2017 796013). The Spanish Science and Innovation Ministry funded C. R. Ranero through the project FRAME CTM2015‐71766‐R and G. Booth‐Rea through the project PID2019‐107138RB‐I00. This is a contribution of the Barcelona Center for Subsurface Imaging, Grup de Recerca 2017 SGR 1662, Generalitat de Catalunya, With the funding support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S), of the Spanish Research Agency (AEI)

In continental settings, seismic failure is generally restricted to crustal depth. Crustal structure is therefore an important proxy to evaluate seismic hazard of continental fault systems. Here we present a seismic velocity model across the Gibraltar Arc System, from the Eurasian Betics Range (South Iberian margin), across offshore East Alboran and Pytheas (African margin) basins, and ending onshore in North Morocco. Our results reveal the nature and configuration of the crust supporting the coexistence of three different crustal domains: the continental crust of the Betics, the continental crust of the Pytheas Basin (south Alboran Basin) and onshore Morocco, and a distinct domain formed of magmatic arc crust under the East Alboran Basin. The magmatic arc under the East Alboran Basin is characterized by a velocity structure containing a relatively high‐velocity lower crust (~7 km/s) bounded at the top and base by reflections. The lateral extension of this crust is mapped integrating a second perpendicular wide‐angle seismic profile along the Eastern Alboran basin, together with basement samples, multibeam bathymetry, and a grid of deep‐penetrating multichannel seismic profiles. The transition between crustal domains is currently unrelated to extensional and magmatic processes that formed the basin. The abrupt transition zones between the different crustal domains support that they are bounded by crustal‐scale active fault systems that reactivate inherited structures. Seismicity in the area is constrained to upper‐middle crust depths, and most earthquakes nucleate outside of the magmatic arc domain. Key Points New velocity model reveals the lithospheric structure under the Betics (South Iberia), the Alboran Basin and the North African margin The East Alboran Basin is floored by magmatic arc crust, while the southern area of the Alboran Basin is floored by continental crust Seismic activity is constrained to the upper‐middle continental crust. Crustal domains are likely bounded by active faults

El jurat, format per Isabel Cacho, Frederic Bartumeus, Francisco J. Doblas, Josep Peñuelas i Silvia Acinas acorda per unanimitat atorgar el premi de ciències ambientals i de la Terra al treball d’investigació científica Upper-plate rigidity determines depth-varying rupture behaviour of megathrust earthquakes dels autors Valentí Sallarès i César R. Ranero, de l’Institut de Ciències del Mar de Barcelona (CSIC) i ICREA, publicat a la revista Nature el 2019. Aquest treball proposa un nou model amb un canvi de paradigma en considerar l’elasticitat dels materials en el comportament dels terratrèmols, de manera que es millora substancialment la previsió de tsunamis

Se puede descifrar el comportamiento de los grandes terremotos en función de la profundidad y estimar su potencial para generar tsunamis de forma más precisa. Un estudio liderado por investigadores del Consejo Superior de Investigaciones Científicas (CSIC) ha desarrollado un modelo que permite predecir características clave de los terremotos así como cuantificar su peligrosidad y su potencial para generar tsunamis. El estudio, elaborado por científicos del Instituto de Ciencias del Mar, se publica en la revista Nature. [...]

American Geophysical Union (AGU) Fall Meeting, 9-13 December 2019, San Francisco, Over the last decades researchers have emphasized on the important role that elastic properties - particularly rigidity - and structural features play in the ¿anomalous¿ shallow rupture of tsunami earthquakes. Yet, we have little understanding on the depth-distribution of such properties and how they influence the rupture of these particular events. Here, we focus on the rupture zone of the 1992 Nicaragua tsunami earthquake (Mw ~7). This event occurred ~20 km down-dip of the megathrust interface but it released large seismic moment near the trench, triggering a devastating tsunami. We analyze the elastic and structural properties of the rupture area from a set of 2D coincident wide-angle (WAS) and multichannel seismic (MCS) lines acquired across and along the rupture area of the 1992 event. We have jointly inverted refracted and reflected travel-times (TT) from both WAS and MCS data to derive P-wave velocity (Vp) information of the overriding plate and the geometry of the megathrust. Combining MCS TTs of reflected arrivals at the megathrust with the ensemble of WAS TTs allowed to enhance the tomographic resolution of our results. This way, we are able to retrieve small-scale topographic variations of the plate interface that would have been omitted with the inversion of WAS TT alone. From Vp we derive other elastic parameters namely, density, S-wave velocity and rigidity using well-established empirical relationships. The results obtained from two parallel sections across the megathrust show that, despite minor local variations, the down-dip distribution of megathrust elastic properties does not present significant variations, sharing a similar trend with depth. The depth-dependence of these properties is consistent with the along-dip distribution of megathrust elastic properties inferred from many other subduction zones of the Pacific, Indonesia, and the Caribbean. We finally use the inferred down-dip distribution of rigidity to compute the slip and the rupture time of the 1992 event. The results agree remarkably well with the estimates of rupture times derived from the inversion of surface waves spectra of the event. These results demonstrate that the along-dip variation of rigidity in the plate interface is key in the up-dip rupture of megathrust earthquakes, particularly, that of tsunami earthquakes