Description: In August and September of 2006 the seismic WESTMED project was conducted in the Western Mediterranean aboard the German RV "Meteor" during the cruise M69/2. Profile 01 (p01) was recorded sucessfully in the Alboran Sea on 11 onshore stations and 16 offshore stations (ocean-bottom seismometers and hydrophones - OBS/OBH). The offshore stations were distributed every 4.5 km. Shoots were fired offshore along a ~150 km line, using two 32-litres BOLT air-guns array operated at 140 bar, fired every 60 s (~200 m). Total length of the seismic line is 360 km, running from the Gulf of Almeria, Spain southward approaching Morocco. Seismic segy data are reduced at 6 km/s. Please note that records from landstations start at 0 sec while OBS and OBH start at -2 sec.

Description: In May of 2019 the US American research vessel Marcus G. Langseth shot a seismic profile along the Emperor Seamounts in the northwest Pacific Ocean. Shots were recorded on 29 ocean-bottom-seismometers (OBS) of the US American Pool and GEOMAR Helmholtz Centre for Ocean Research Kiel. Seismic data in SEGY format of the GEOMAR OBS are here available from PANGAEA Datacenter. Please note that the data have a time offset of 1 sec and a reduction velocity of 8 km/s. The SEGY data from the US American OBS are available at the Incorporated Research Institution for Seismology (IRIS) (see also link in station file) under the network code ZU. The seismic survey was funded by the US American National Science Foundation (Awards OCE17-37243, OCE17-37245).

Description: We present the results of our analysis of the seismogenic and tsunamigenic structure of the Alboran Basin (westernmost Mediterranean). In particular, we upload two different types of files: 1) the 3D model of a fault plane and 2) the results of the numerical tsunami simulations for the 4 main faults in the area, the Alboran Ridge Fault System (ARFS), the Carboneras Fault System (CFS), the Yusuf Fault System (YFS) and the Al-Idrissi Fault System (AIFS). In order to perform a first approach to the tsunamigenic potential of these active structures, different models have been run with different input parameters (see metadata description). The fault plane has been obtained based on the analysis of active seismic data collected in the area, and the tsunami simulations have been obtained using the HySEA code. For details about the method, and the discussion of the different parameters used in the models, please see the related article "A first appraisal of the seismogenic and tsunamigenic potential of the largest fault systems of the westernmost Mediterranean" (Gómez de la Peña et al., Marine Geology, 2022).

Description: In May of 2019 the US American research vessel Marcus G. Langseth shot seismic profile p01 across the Emperor Seamounts in the northwest Pacific Ocean. Shots were recorded on 27 ocean-bottom-seismometers (OBS) of the US American Pool and GEOMAR Helmholtz Centre for Ocean Research Kiel. Seismic data in SEGY format of the GEOMAR OBS are here available from PANGAEA Datacenter. Please note that the data have a time offset of 1 sec and a reduction velocity of 8 km/s. The SEGY data from the US American OBS are available at the Incorporated Research Institution for Seismology (IRIS) under the network code ZU. The seismic survey was funded by the US American National Science Foundation (Awards OCE17-37243, OCE17-37245).

Description: Complex multifault earthquake ruptures involving secondary faults emphasize the necessity to characterize their seismogenic potential better and study their relationship with major faults to improve the seismic hazard assessment of a region. High-resolution geophysical data were interpreted to make a detailed characterization of the Averroes Fault and the North Averroes Faults, which are poorly known secondary right-lateral strike-slip faults located in the central part of the Alboran Sea (western Mediterranean). These faults appear to have evolved since the Pliocene as part of a distributed dextral strike-slip shear zone in response to local strain engendered by the diverging movement of the Carboneras Fault to the north, and the Yusuf and Alboran Ridge faults to the south. In addition, the architecture of these faults suggests that the Averroes Fault may eventually link with the Yusuf fault, thus leading to a higher seismogenic potential. Therefore, these secondary faults represent a hitherto unrecognized seismogenic hazard since they could produce earthquakes up to moment magnitude (Mw) 7.6. Our results highlight the importance of the role played by secondary faults in a specific kinematic framework. Their reciprocal linkage and their mechanical relationship with the main faults could lead to future complex fault ruptures. This information could improve fault source and earthquake models used in seismic and tsunami hazard assessment in this and similar regions.

Description: The Alboran Basin in the westernmost Mediterranean hosts the orogenic boundary between the Iberian and African plates. Although numerous geophysical studies of crustal structure onshore Iberia have been carried out during the last decade, the crustal structure of the Alboran Basin has comparatively been poorly studied. We analyze crustal‐scale images of a grid of new and reprocessed multichannel seismic profiles showing the tectonic structure and variations in the reflective character of the crust of the basin. The nature of the distinct domains has been ground‐truthed using available basement samples from drilling and dredging. Our results reveal four different crustal types ‐domains‐ of the Alboran Basin: a) a thin continental crust underneath the West Alboran and Malaga basins, which transitions to b) a magmatic arc crust in the central part of the Alboran Sea and the East Alboran Basin, c) the North‐African continental crust containing the Pytheas and Habibas sub‐basins, and d) the oceanic crust in the transition towards the Algero‐Balearic Basin. The Alboran Basin crust is configured in a fore‐arc basin (West Alboran and Malaga basins), a magmatic arc (central and East Alboran), and a back‐arc system in the easternmost part of the East Alboran Basin and mainly Algero‐Balearic Basin. The North‐African continental crust is influenced by arc‐related magmatism along its edge, and was probably affected by strike‐slip tectonics during westward migration of the Miocene subduction system. The distribution of active tectonic structures in the current compressional setting generally corresponds to boundaries between domains, possibly representing inherited lithospheric‐scale weak structures.

Description: Highlights • New high-resolution bathymetry and MCS images of the Palomares margin are presented. • Main geomorphological and tectonic features along the margin are analyzed. • Bathymetry is mainly controlled by erosive and halokinesis processes. Abstract The Palomares continental margin is located in the southeastern part of Spain. The margin main structure was formed during Miocene times, and it is currently part of the wide deformation zone characterizing the region between the Iberian and African plates, where no well-defined plate boundary occurs. The convergence between these two plates is here accommodated by several structures, including the left lateral strike–slip Palomares Fault. The region is characterized by sparse, low to moderate magnitude (Mw 〈 5.2) shallow instrumental earthquakes, although large historical events have also occurred. To understand the recent tectonic history of the margin we analyze new high-resolution multibeam bathymetry data and re-processed three multichannel seismic reflection profiles crossing the main structures. The analysis of seafloor morphology and associated subsurface structure provides new insights of the active tectonic features of the area. In contrast to other segments of the southeastern Iberian margin, the Palomares margin contains numerous large and comparatively closely spaced canyons with heads that reach near the coast. The margin relief is also characterized by the presence of three prominent igneous submarine ridges that include the Aguilas, Abubacer and Maimonides highs. Erosive processes evidenced by a number of scars, slope failures, gullies and canyon incisions shape the present-day relief of the Palomares margin. Seismic images reveal the deep structure distinguishing between Miocene structures related to the formation of the margin and currently active features, some of which may reactivate inherited structures. The structure of the margin started with an extensional phase accompanied by volcanic accretion during the Serravallian, followed by a compressional pulse that started during the Latemost Tortonian. Nowadays, tectonic activity offshore is subdued and limited to few, minor faults, in comparison with the activity recorded onshore. The deep Algero-Balearic Basin is affected by surficial processes, associated to halokinesis of Messinian evaporites.

Description: About 25% of the Earth’s mid-ocean ridges spread at ultraslow rates of less than 20 mm/yr. However, most of these ultraslow spreading ridges are located in geographically remote areas, which hamper investigation. Consequently, how the crust forms and ages at such spreading centres, which traditionalmodels predict to be magma-starved and cold, remains poorly understood. One of the most accessible ultra-slow spreading centres is the Mid Cayman Spreading Centre (MCSC), in the Caribbean Sea, with spreading rates of ~15-17 mm/yr.CAYSEIS project was proposed to survey the Cayman Trough area in order to obtain new data that constraints the nature of the crust, tectonic structures, lithologies outcropping and hydrothermal processes taking place in this area. Understanding the sub-seabed geophysical structure of the MCSC is key to understanding not only the lithologies and structures exposed at the seabed, but more fundamentally, how they are related at depth and what role hydrothermal fluid flow plays in the geodynamics of ultraslow spreading. CAYSEIS was a joint and multidisciplinary programme of German, British and US American top tier scientists designed for the obtaining of a new high-quality dataset, including 3D Wide-Angle Seismic (WAS), magnetic, gravimetric and seismological data.During the CAYMAN project, we took leverage of the CAYSEIS dataset to invert a 3D tomographic model of the Cayman Trough lithosphere using the Tomo3D code (Meléndez et al., 2015; 2019). This is one of the first times that the Tomo3D code is used for 3D inversion of real datasets. Thus, we are checking our results comparing them with tomographic inversions of 2D lines and testing the different parameters to obtain the more accurate and higher resolution model as possible. The results of this experiment will show not only the lithospheric structure along and across the MSCS, including the exhumed Ocean Core Complexes in the surrounding areas, but the 3D lithospheric configuration of the region which is important to understand the crustal formation processes and the evolution of ultra-slow spreading settings.