Gràcia, Eulàlia ... et al.-- Inciativa Ibérica para el Estudio de las Fallas Activas, Tercera Reunión Ibérica sobre Fallas Activas y Paleosismología IBERFAULT 2018 - Third Iberian Meeting on Active Faults and Paleoseismology, 11-13 June 2018, Alicante, Spain.-- 4 pages, 4 figures, Here we present an overview of the three largest continental strike-slip fault systems in the Alboran Basin: Carboneras, Yusuf and Al-Idrissi. Our dataset results from an integration of different types of acoustic and seismic data acquired during five marine cruise during the past 10 years. A multiscale approach utilizing newly acquired AUV near-bottom bathymetry (1-m resolution), shipboard bathymetry, high-resolution seismics (Sparker) and deep penetration multichannel seismics (MCS) data is used. According to fault trend, geometry and time of activity, fault systems are divided in different segments. These large fault systems are able to generate Mw>6.0 to 7.4 earthquakes, which may represent a significant seismic hazard to the neighbourin areas, We acknowledge financial support from MINECO through Projects EVENT (CGL2006-12861-C02-02), SHAKE (CGL2011-30005-C02-02), ESF >TopoEurope> TOPOMED (CGL2008-03474-E/BTE), INSIGHT (CTM2015-70155-R)., Peer Reviewed

Inciativa Ibérica para el Estudio de las Fallas Activas, Tercera Reunión Ibérica sobre Fallas Activas y Paleosismología IBERFAULT 2018 - Third Iberian Meeting on Active Faults and Paleoseismology, 11-13 June 2018, Alicante, Spain.-- 4 pages, 2 figures, Large earthquakes, submarine landslides and their occasional tsunami originated are geohazards of great societal concern because of the impact on the world economies and coastal populations. Dramatic examples of such events include the 2004 northern Sumatra and 2011 Tohoku earthquakes and tsunamis. However, earthquakes of magnitude > 7.0 in areas of relatively slow tectonic deformation and with long recurrence intervals, such as the external part of the Gulf of Cadiz, might also have a significant impact as the well-known case of the destructive 1755 Lisbon earthquake, related submarine landslides, and resulting tsunami. Although the Gulf of Cadiz is one of the highest geohazard zones in Europe, we currently lack appropriate understanding of both the rupture areas and stress-state of the faults and sediments in which such catastrophic events originated. The relatively great water depths, poor accuracy on the location of moderate-to¬-high magnitude earthquakes, lack of understanding of subsurface hydrology and the few constraints on ages of the sedimentary sequences hinder an appropriate understanding of location and characteristics of earthquake ruptures and associated submarine landslides in the Gulf of Cadiz. Our hypothesis is that such understanding can only be developed by using ultra-high resolution (UHR) tools capable of providing the characterization of faults, submarine landslides, and fluid escape structures while being able to work in deep waters such as those of the external Gulf of Cadiz. INSIGHT tackles this problem by using state-of ¬the-art UHR techniques such as microbathymetry, 2D high-resolution seismic data, and sampling using piston cores. We aim at 1) Map in detail the active faults with largest seismogenic potential, 2) Accurately determine the seismic parameters of these faults, 3) Characterize associated submarine landslides, 4) Assess the likelihood of recent submarine landslides activation, and finally, 5) Evaluate the seismogenic and tsunamigenic potential of the largest tectonic sources, We acknowledge financial support from MINECO through Project INSIGHT (CTM2015-70155-R), Peer Reviewed

20th International Sedimentological Congress (ISC), 13-17 August 2018, Quebec City, Canada.-- 1 page, The Marques de Pombal landslide deposit, with its estimated volume of 1.3 km2, is located in the Alentejo Basin, the Northern section of the Gulf of Cadiz (SW Iberian Margin). Gravity core analyses sampled in the Marques de Pombal depositional area reveal that multiple landslide and turbidity events contributed to the deposit formation1,2. Considering the moderate-to-large-magnitude seismic activity of the area, earthquakes are the main triggering candidate for the mass wasting events. The Great Lisbon catastrophic earthquake of 1755 may also have contributed to the landslide’s deposit. This work reconstructs the sedimentary, stratigraphic and geotechnical conditions of the area of interest before the 1755 earthquake and aims to evaluate the development of excess pore pressure in order to balance pre-conditioning factors vs triggering mechanisms in onset of slope failure. Seismic profiles, swath bathymetry deep-towed side-scan sonar mosaics and well and log data from the IODP 339 expedition have been used to construct a stratigraphic model of the slope failure area. Gravity core samples are used to understand development of permeability, compressibility and strength with burial depth. These data are used to build a numerical finite elements model, which aims to determine the relationship between continental margin development and its hydrogeological evolution, This work was supported and financed by the SLATE (H2020-MSCA-ITN-2016-721403)–“Submarine landslides and their impact on continental margins ”European Training Network and the Spanish project “ImagiNg large SeismogenuIc and tsunamiGenic structures of the Gulf of Cadiz with ultra-High resolution Technologies” (INSIGHT(CTM2015-70155-R), Peer Reviewed

20th International Sedimentological Congress (ISC), 13-17 August 2018, Quebec City, Canada.-- 1 page, An updated version of the submarine landslide database of the Mediterranean Sea1 contains 955 MTDs and 2608 failure scars showing that submarine landslides are ubiquitous features along Mediterranean continental margins. Their distribution reveals that major deltaic wedges display the larger submarine landslides, while tectonically active margins are characterized by relatively small failures. In all regions, landslide size distributions display power law scaling for landslides > 1 km3. We find consistent differences on the exponent of the power law depending on the tectonic setting. Active margins present steep slopes of the frequency-magnitude relationship whereas passive margins tend to display gentler slopes. This pattern likely responds to the common view that tectonically active margins have numerous but small failures, while passive margins have larger but fewer failures. Available age information suggests that failures exceeding 1000 km3are infrequent and may recur every ~40 kyr. Smaller failures that can still cause significant damage might be relatively frequent, with failures> 1 km3likely recurring every 40 years. This comprehensive database highlights that our knowledge of submarine landslide dynamics within time is limited to a few tens of thousands of years. Available data suggest that submarine landslides may preferentially occur during lowstand periods, but no firm conclusion can be made on this respect, as only 149 landslides (out of 955 included in the database) have relatively accurate age determinations. The temporal pattern and changes in frequency-magnitude distribution suggest that sedimentation patterns and pore pressure development have had a major role in triggering slope failures and control the mass wasting sediment flux to the deep basin, This work was supported and financed by the SLATE (H2020-MSCA-ITN-2016-721403) “Submarine landslides and their impact on continental margins” European Training Network and the Spanish project “ImagiNg large SeismogenIc and tsunamiGenic structures of the Gulf of Cadiz with ultra-High resolution Technologies” (INSIGHT (CTM2015- 70155-R), Peer Reviewed

20th International Sedimentological Congress (ISC), 13-17 August 2018, Quebec City, Canada.-- 1 page, The relationship between submarine active seismogenic faults and associated slope failures, especially in low-convergence areas, is still poorly known. Here we present a case study from the SW Iberian Margin, at the boundary between the African and Eurasian plates. Despite low plate convergence (4-5 mm/yr), this area has been the source of the largest earthquakes and tsunamis in western Europe1, such as the 1969 Earthquake (Mw8) and the 1 November 1755 Lisbon Earthquake (estimated Mw8.5). Here we present AUV-and shipboard-bathymetry maps, high-resolution sidescan sonar data, multichannel seismic profiles and sediment cores that allow us to characterize, with unprecedented resolution, the relationship between the fault system and related slope failures. The Marques de Pombal Fault is an active 50-km-long west-verging monocline thrust cutting through the Plio-Quaternary units2. Deformation is accommodated by thrusting and folding. Sidescan sonar maps across the MPF reveal a large (260 km2) translational landslide and debris flow. Successive slope failures located at the base of the fault scarp provide evidence of cyclic fault activity. The most recent slide (230 yr BP), may have been triggered by the 1755 Lisbon earthquake. By dating previous slide deposits, we obtained a recurrence period of 2000 yr3, suggesting cyclic activity of the Marques de Pombal Fault, We thank funding by ETNSLATE (H2020-MSCA-ITN-2016-721403) & INSIGHT (CTM2015-70155-R) projects, Peer Reviewed

IV Reunión Ibérica sobre Fallas Activas y Paleosismología, del 7 al 10 de septiembre de 2022 en Teruel.-- 3 pages, 1 figure, [EN] The southwest Iberia margin hosted the 1755 Lisbon earthquake and ensuing tsunami, one of the most destructive natural events in European history. Here we present a plausible source and mechanism responsible for this event combining geophysical data and numerical tsunami modelling. Our results show that an intra-plate, lithospheric-scale thrust fault located at the Horseshoe Abyssal Plain coincides with the location and focal mechanisms of the largest regional earthquakes and is likely to have suitable dimensions and fault-rock properties to account for the magnitude of the 1755 event. The tsunami simulations with the Horseshoe Abyssal plain Thrust as the source reproduce reported tsunami energy propagation patterns, arrival-times and run up heights more successfully than any other proposed source, [ES] El margen suroeste de Iberia es la región donde ocurrió el terremoto de Lisboa de 1755 y el posterior tsunami, uno de los eventos naturales más destructivos de la historia europea. Aquí presentamos una fuente plausible y un mecanismo responsable de este evento que combina datos geofísicos y modelos numéricos de tsunamis. Nuestros resultados muestran que un cabalgamiento de escala litosférica intraplaca ubicado en la llanura abisal de Horseshoe coincide con la ubicación y los mecanismos focales de los terremotos instrumentales más grandes ocurridos en la región, y es probable que tenga las dimensiones y propiedades de roca de falla adecuadas para explicar la magnitud del evento de 1755. Las simulaciones de tsunami con el Horseshoe Abyssal Plain Thrust como fuente reproducen los patrones de propagación de la energía del tsunami, los tiempos de llegada y las alturas máximas de ola con más éxito que cualquier otra fuente propuesta, This work has been done in the framework of projects INSIGHT (CTM2015-70155-R) and STRENGHT (PID2019-104668RB-I00), and with the funding support of the ‘Severo Ochoa Centre of Excellence’ accreditation, of the Spanish “Ministerio de Ciencia, Innovación y Universidades”. 2020-2023 (CEX2019-000928-S). First author’s work was done in the framework of the “Juan de la Cierva-Incorporación” (IJCI-2017-33838) and “Severo Ochoa 2020 Postdoctoral Extension” (PEF-SO-03) fellowships, Peer reviewed

Gas in Marine Sediments Conference (GIMS), 23-27 October 2023, Cádiz, Spain, Mud volcanoes (MVs) are expulsion features ubiquitously present in areas of tectonic convergence both on land and on the seafloor. Eruptions are deemed crucial to understand the regional geology and fluid- sediment interactions. However, the main drivers behind these sporadic bursts in activity still remain fairly obscure. It is hypothesized that different events can trigger MVs eruptions, therefore originating a plethora of different effects with corresponding ejecta, channeled through the main conduits. Of all the MVs triggers, earthquakes (EQs) are the only ones for which a direct cause-effect relationship has been already established (e.g. Menapace et al., 2017). The Gulf of Cadiz (GoC) has arguably one of the best settings for the study of MVs and paleoseismology, due to the presence of an accretionary wedge with active fluid and solid expulsion structures (>90 MVs, at least three major transform faults, several pockmarks fields) and because of the numerous large magnitude EQs happened in the past, which are well preserved in the sedimentological record (Gracia et al., 2010). Recently, three major seagoing expeditions led by MARUM and the ICM-CSIC set out to investigate the episodicity and nature of MVism in the GoC (Menapace et al., 2021), as well as its relationship with the tectonic and seismic history of the region. We present here the main results from the aforementioned expeditions, which contributed to shed new light on the fluid and solid cycles of the SW Iberian Margin with an unprecedented level of detail, highlighting how a plethora of different processes is, in fact, fueled by and contributing to the GoC mud volcanism, This study was funded by the H2020 MSCA-IF action [GA No. 101018321] and by the Austrian Science Fund (FWF) [M 3146-N] and acknowledges the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S). Data from the “ImagiNg large SeismogenIc and tsunamiGenic structures of the Gulf of Cadiz with ultra-High resolution Technologies (INSIGHT)” project were used [GA No. CTM2015-70155-R], Peer reviewed