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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)

Neolithic is a period characterized by the development of new technologies and a broader use of organic and inorganic materials. Some of the metallic minerals were used for making ornaments and pigments before their use as metals (copper or iron ores are a clear example of this exploitation). Galena (lead sulfide) is not usually mentioned in this period, but a new research find a frequent presence of blocks of galena since the Early Neolithic in several Catalan sites. Just in one case was found as a grave-good (female grave in Masdervenger, Tarragona), but most of them come from domestic context. Galena is not a good material to be worked using knapping methods due to its cubic crystals and fracture properties: one of the striking features is a fine cleavage. Nor does it have properties that make possible to use it as a fire starter, to generate a spark. However, its metallic luster and weight could attract the attention of the people. This early contact with galena however did not drive to a metallic use of lead. It is intriguing the fact that lead beads were common (hundreds) in southern France Chalcolithic, where a similar pattern of galena use during the Neolithic (since Early Chasséen) is also known; on the contrary just only one lead bead was found in Catalonia (Cova de L'Heura, Tarragona) and ist lead isotope signature matches the local lead mines. This paper includes a provenance study by Lead Isotope Analysis (using MC-ICP-MS ) to understand the local pattern of exploitation of galena, with the Molar-Belmunt-Falset mines in Tarragona and The Martorell/Begues mines in Barcelona as the main and only areas supplying the galena during the Neolithic.

European Geosciences Union (EGU) General Assembly 2018, 8-13 April 2018, Vienna, Austria.-- 1 page., The deep structure of the Alboran Basin (westernmost Mediterranean) has been under debate since the first surveys in the late 1980’s. Although the regional crustal and upper mantle structure has been extensively studied recently (i.e. global tomography, receiver function analysis or full-waveform inversion) the lithosphere underneath the Alboran Basin remains inadequately imaged, as the resolution of the crustal model is limited due to sparse data, inhibiting a precise characterization of the crust underneath the basin. The deep structure of the Alboran Basin is directly linked to the seismogenic potential of this area, as the main faults seem to be located at the edges of the crustal domains. Thus, an accurate seismic characterization of the crustal domains of the Alboran Basin and the transition between them is key to improve our understanding of the seismogenic potential of the faults in this complex area. Based on multichannel seismic reflection studies (i.e. TOPOMED project), with seafloor and basement groundtruthing through available drill and dredge samples, four different crustal domains have been defined for the area: (i) a thin continental domain (West Alboran and Malaga basins), (ii) the magmatic arc domain (East Alboran Basin), (iii) the North-African continental domain (South Alboran, Pytheas and Habibas basins) and (iv) oceanic crust (Algero-Balearic Basin). Unfortunately, basement dredges and well data are scarce, and, to a better understand of the deep structure of the Alboran Basin, wide-angle seismic deep-penetrating data are needed. Here we present the velocity and density model obtained from the inversion of profile P01 (WESTMED project), running from the south of Iberia (Almeria) to the north African margin (east of Nador). This profile includes 24 ocean bottom hydrophones and seismometers (OBH/OBS) with a spacing

The Western Mediterranean Sea is a natural laboratory to study the processes of continental extension, rifting and back-arc spreading in a convergent setting caused by rollback of fragmented subducting oceanic slabs during the latest phase of consumption of the Tethys ocean, leading to rapid extension in areas characterized by a constant convergence of the African and European Plates since Cretaceous time. Opening of the Algerian-Balearic Basin was governed by a southward and westward retreating slab 21 to 18 Myr and 18 to15 Myr ago, respectively. Opening of the Tyrrhenian Basin was controlled by the retreating Calabrian slab 6 to 2 Myr ago. Yet, little is known about the structure of the rifted margins, back-arc extension and spreading. Here we present results from three onshore/offshore seismic refraction and wide-angle lines and two offshore lines sampling passive continental margins of southeastern Spain and to the south of the Balearic promontory and the structure of the Tyrrhenian Basin to the north of Sicily. Seismic refraction and wide-angle data were acquired in the Algerian-Balearc Basin during a cruise of the German research vessel Meteor in September of 2006 and in the Tyrrhenian Sea aboard the Spanish research vessel Sarmiento de Gamboa in July of 2015. All profiles sampled both continental crust of the margins surrounding the basins and extend roughly 100 km into the Algerian-Balearic and the Tyrrhenian Basins, yielding constraints on the nature of the crust covering the seafloor in the basins and adjacent margins. Crust in the Algerian-Balearic basin is roughly 5-6 km thick and the seismic velocity structure mimics normal oceanic crust with the exception that lower crustal velocity is 24 km under SE Spain and the Balearic Islands, displaying typical features and structure of continental crust. Offshore Sicily, continental crust reaches 22 km. However, the Tyrrhenian Basin indicates a lithosphere with velocities increasing continuously from3 km/s to 7.5 km/s, mimicking features attributed to un-roofed and hence serpentinized mantle. Therefore, even though the opening of both basins was controlled by slab rollback, the resulting structures of the basins indicate striking differences. It is interesting to note that the continent/ocean transition zone of the margins did not show any evidence for high velocity lower crustal rocks, in contrast to what has been sampled in Western Pacific arc/back-arc systems.

The analysis of background seismic noise variations in the proximity of river channels has revealed as a useful tool to monitor river flow, even for modest discharges. Nevertheless, this monitoring is usually carried on using temporal deployments of seismic stations. The CANF seismic broad-band station, acquiring data continuously since 2010 and located inside an old railway tunnel in the Central Pyrenees, at about 400 m of the Aragón River channel, provides an excellent opportunity to enlarge this view and present a long term monitoring of a mountain river. Seismic signals in the 2-10 Hz band clearly related to river discharges have been identified in the seismic records. Discharge increases due to rainfall, large storms resulting in floods and snowmelt periods can be discriminated from the analysis of the seismic data. Up to now, two large rainfall events resulting in large discharge and damaging floods have been recorded, both sharing similar properties which can be used to implement automatic procedures to identify seismically potentially damaging floods. Another natural process that can be characterized using continuouly acquired seismic data is mountain snowmelt, as this process results in characteristic discharge patterns which can be identified in the seismic data. The time occurrence and intensity of the snowmelt stages for each season can be identified and the 5 seasons available so far compared to detect possible trends The so-called fluvial seismology can also provide important clues to evaluate the beadload transport in rivers, an important parameter to evaluate erosion rates in mountain environments. Analyzing both the amplitude and frequency variations of the seismic data and its hysteresis cycles, it seems possible to estimate the relative contribution of water flow and bedload transport to the seismic signal. The available results suggest that most of the river-generated seismic signal seems related to bed load transportation, while water turbulence is only significant above a discharge thres.hold, Founding: MISTERIOS project, CGL2013-48601-C2-1-R

In recent years the analysis of background seismic noise variations in the proximity of river channels has revealed as a useful tool to monitor river flow, even for modest discharges. Nevertheless, this monitoring is usually carried on using temporal deployments of seismic stations. The LC.CANF seismic broad-band station, acquiring data continuously since 2011 and located inside an old railway tunnel in the Central Pyrenees, at about 400 m of the Aragón River channel, provides an excellent opportunity to enlarge this view as it offers a long term monitoring of a mountain river. Data from this site, located at higher distance from the river channel than is most of fluvial seismology experiments, can provide additional clues on the discrimination between vibrations related to turbulent water flow and and those generated by bedload transport. Up to now, two large rainfall events resulting in large discharge and damaging floods have been recorded, both sharing similar properties and hence making possible the identification of such hazards from the sole inspection of seismic data. The time occurrence and intensity of the snowmelt stages for each season have been identified and analyzed from the characteristics of the associated seismic records. In particular, the spectrograms of such episodes show a rich pattern of intensity and spectral variations. The availability of data covering 6 snow seasons allos to compare their variations in a long term scale. Since 2015 we are operating 2 additional stations located beside the Cinca and Segre Rivers, also in the Pyrenean range. First results confirm that the river-generated signal can be identified in the seismic data, even if it is often overlapped with wind-generated signal. Our objective is now to implement automatic procedures to identify seismic signals generated by large floods using data from seismic stations located near mountain rivers. On the other hand, we want to develop synthetic models of the seismic signal expected from bedload transport and water flow turbulence, with the final aim of using seismic data to estimate the bedload charge transported and hence constrain erosion studies in mountain environments. ., (Founding: MISTERIOS project, CGL2013-48601-C2-1-R)

We present a new 3-D shear velocity model of the western Mediterranean from the Pyrenees, Spain, to the Atlas Mountains, Morocco, and the estimated crustal and lithospheric thickness. The velocity model shows different crustal and lithospheric velocities for the Variscan provinces, those which have been affected by Alpine deformation, and those which are actively deforming. The Iberian Massif has detectable differences in crustal thickness that can be related to the evolution of the Variscan orogen in Iberia. Areas affected by Alpine deformation have generally lower velocities in the upper and lower crust than the Iberian Massif. Beneath the Gibraltar Strait and surrounding areas, the crustal thickness is greater than 50 km, below which a high-velocity anomaly (>4.5 km/s) is mapped to depths greater than 200 km. We identify this as a subducted remnant of the NeoTethys plate referred to as the Alboran and western Mediterranean slab. Beneath the adjacent Betic and Rif Mountains, the Alboran slab is still attached to the base of the crust, depressing it, and ultimately delaminating the lower crust and mantle lithosphere as the slab sinks. Under the adjacent continents, the Alboran slab is surrounded by low upper mantle shear wave velocities (Vs, This research was funded by the U.S. National Science Foundation EAR- 0808939. The deployment of the IberArray broadband seismic network is part of the CONSOLIDER-Ingenio 2010 TOPO-IBERIA (CSD2006-00041: Geosciences in Iberia: Integrated studies on Topography and 4-D Evolution) grant from the Spanish Ministry of Science and Innovation. Additional funding was provided by the Spanish ministry under grants CGL2010-17280, CGL2006-01171,CGL2009-09727, and CGL2007-63889,and by Generalitat de Catalunya under grant 2009 SGR 6.

The analyses of wide-angle reflections of controlled source experiments and receiver functions calculated from teleseismic events provide consistent constraints of an over-thickened crust beneath the Rif Cordillera (North Morocco). Regarding active source data, we investigate now offline arrivals of Moho-reflected phases recorded in RIFSIS project to get new estimations of 3D crustal thickness variations beneath North Morocco. Additional constrains on the onshore-offshore transition are derived from onland recording of marine airgun shots from the coeval Gassis-Topomed profiles. A regional crustal thickness map is computed from all these results. In parallel, we use natural seismicity data collected throughout TopoIberia and PICASSO experiments, and from a new RIFSIS deployment, to obtain teleseismic receiver functions and explore the crustal thickness varia- tions with a H-κgrid–search approach. The use of a larger dataset including new stations covering the complex areas beneath the Rif Cordillera allow us to improve the resolution of previous contributions, revealing abrupt crustal changes beneath the region. A gridded surface is built up by interpolating the Moho depths inferred for each seismic station, then compared with the map from controlled source experiments. A remarkably consistent image is observed in both maps, derived from completely independent data and methods. Both approaches document a large modest root, exceeding 50 km depth in the central part of the Rif, in contrast with the rather small topographic elevations. This large crustal thickness, consistent with the available Bouguer anomaly data, favor models proposing that the high velocity slab imaged by seismic tomography beneath the Alboran Sea is still attached to the lithosphere beneath the Rif, hence pulling down the lithosphere and thickening the crust. The thickened area corresponds to a quiet seismic zone located between the western Morocco arcuate seismic zone, the deep seismicity area beneath western Alboran Sea and the superficial seismicity in Alhoceima area. Therefore, the presence of a crustal root seems to play also a major role in the seismicity distribution in northern Morocco.

The Iberian Peninsula and Morocco, separated by the Alboran Sea and the Algerian Basin, constitute the westernmost Mediterranean. From north to south this region consists of the Pyrenees, the result of interaction between the Iberian and Eurasian plates; the Iberian Massif, a region that has been undeformed since the end of the Paleozoic; the Central System and Iberian Chain, regions with intracontinental Oligocene-Miocene deformation; the Gibraltar Arc (Betics, Rif and Alboran terranes) and the Atlas Mountains, resulting from post-Oligocene subduction roll-back and Eurasian-Nubian plate convergence. In this study we analyze data from recent broad-band array deployments and permanent stations on the Iberian Peninsula and in Morocco (Spanish IberArray and Siberia arrays, the US PICASSO array, the University of Munster array, and the Spanish, Portuguese, and Moroccan National Networks) to characterize its lithospheric structure. The combined array of 350 stations has an average interstation spacing of ∼60 km, comparable to USArray. We have calculated the Rayleigh waves phase velocities from ambient noise for short periods (4 s to 40 s) and teleseismic events for longer periods (20 s to 167 s). We inverted the phase velocities to obtain a shear velocity model for the lithosphere to∼200 km depth. The model shows differences in the crust for the different areas, where the highest shear velocities are mapped in the Iberian Massif crust. The crustal thickness is highly variable ranging from∼25 km beneath the eastern Betics to∼55km beneath the Gibraltar Strait, Internal Betics and Internal Rif. Beneath this region a unique arc shaped anomaly with high upper mantle velocities (>4.6 km/s) at shallow depths (

The complex tectonic interaction processes between the European and African plates at the Western Mediterranean since Mesozoic times have left marked imprints in the present-day crustal architecture of this area, particularly as regarding the lateral variations in crustal and lithospheric thicknesses. The detailed mapping of such variations is essential to understand the regional geodynamics, as it provides major constraints for different seismological, geophysical and geodynamic modeling methods both at lithospheric and asthenospheric scales. Since the 1970s, the lithospheric structure beneath the Iberian Peninsula and its continental margins has been extensively investigated using deep multichannel seismic reflection and refraction/wide-angle reflection profiling experiments. Diaz and Gallart (2009) presented a compilation of the results then available beneath the Iberian Peninsula. In order to improve the picture of the whole region, we have now extended the geographical area to include northern Morocco and surrounding waters. We have also included in the compilation the results arising from all the seismic surveys performed in the area and documented in the last few years. The availability of broad-band sensors and data-loggers equipped with large storage capabilities has allowed in the last decade to boost the investigations on crustal and lithospheric structure using natural seismicity, providing a spatial resolution never achieved before. The TopoIberia-Iberarray network, deployed over Iberia and northern Morocco, has provided a good example of those new generation seismic experiments. The data base holds∼300 sites, including the permanent networks in the area and hence forming a unique seismic database in Europe. In this contribution, we retrieve the results on crustal thickness presented by Mancilla and Diaz (2015) using data from the TopoIberia and associated experiments and we complement them with additional estimations beneath the Rif Cordillera arising from more recent deployments. We have now included also the sparse results in the region previously published, with the aim of checking the consistency of the results, hence giving more strength to the retained features. Combining the Moho depth values coming from controlled source and natural seismicity experiments has finally allowed us to build up a high quality grid of the region at crustal scale, which is completed in the non-sampled areas by the wide-scale CRUST1.0 model. The final picture evidences the geodynamic diversity of the area, including crustal imbrication in the Pyrenean range, a large and relatively undisturbed Variscan Massif in the center of Iberia and a probable delamination process beneath the Gibraltar Arc. Crustal thicknesses range from values around 15 km in continental margins (Cantabrian margin and Valencia Trough) to depths exceeding 50 km beneath the Pyrenees and the Rif Cordillera. A new 3D model of those variations is presented here to illustrate and summarize such large variations

The IberArray instrumental platform, part of the TopoIberia project, has provided a huge increase on the geophysical datasets available to constrain the structure and dynamics of the mantle beneath the Iberian Peninsula. Receiver Functions have allowed to map accurately large crustal thickness variations. Volume and surface wave tomographies have been obtained for the crust and the upper mantle, allowing to define the geometry of the highvelocity slab beneath Alboran. The 410-km and 660-km discontinuities have been investigated using novel crosscorrelation/stacking techniques. Finally, the measurement and interpretation of the anisotropic parameters has provided a new insight on the asthenospheric flow., Este trabajo ha recibido financiación procedente proviene del Ministerio de Economía y Competitividad (MINECO) mediante los proyectos CSD 2006-00041 (TopoIberia), Red TopoIberia-Iberarray CGL2014-54582-REDC] y de la subvención de la Generalitat de Catalunya 2009SGR996.

In recent years the analysis of background seismic noise variations in the proximity of river channels has revealed as a useful tool to monitor river flow, even for modest discharges. We will focus here in the application of this methodology to study the snowmelt cycle in an Pyrenean valley during the last 5 years, using data from the seismic geophysical station located inside the Canfranc Underground Laboratory (Central Pyrenees). Diaz et al. (2014) first identified in the seismic data the signature of river flow increases associated to snowmelt episodes in the catchment area of the Aragon River, based on the marked correlation between the seismic energy variations in the 2-8 Hz frequency band and the estimated variations in water resources from snowfall. The analysis of seismic data during the snowmelt periods allows to identify a clear 24h cycle, with energy increasing from about 14:00 GMT, remaining at a relatively high level for 12 hours and then smoothly vanishing. The spectrogram reveals richer information, as clear variations in the frequency content can be detected during the time intervals in which the amplitude of the seismic signal remains constant. The data available so far allow to compare the evolution of snowmelt in five seasons with very different hydrological behavior. The 2011 and 2012 seasons have been dry, with snow volumes 30-50 % beneath the average values, while the 2013, 2014 and in particular the 2015 seasons have been largely above the mean. Those variations are reflected in the seismic data, which allow to monitor the time occurrence of the main snowmelt stages for each season and to estimate the intensity of the different snowmelt episodes. Therefore, seismic data can be useful for long term monitoring of snowmelt in Alpine-style mountains.

The seismic experiments conducted in northern Morocco during the last decade have provided detailed information on the geometry of the crust beneath the Rif Cordillera. In the mainframe of the RIFSIS project, 2D models of velocity / depth along two 300 km-long profiles oriented NS and EW, have revealed the presence of a thickened area, with depths of Moho near 50 km under the External Rif. The crustal geometry of this area has also been investigated using passive seismic data using methods based on the analysis of receiver functions and obtaining consistent values. The origin of the thickening under the External Rif is related to the slab of Alboran, which would still be connected to the lithosphere under this area, hence causing the crustal deformation., La financiación para este trabajo proviene del Ministerio de Economía mediante los proyectos CGL2009-09727 (RIFSIS), CSD 2006-00041 (TopoIberia), CGL2007-63889 (SIMA), CGL2008-3474 (TopoMed) y de la subvención de la Generalitat de Catalunya 2009SGR996. Hemos utilizado también datos del proyecto PICASSO, financiado por el proyecto EAR0808939 de la NSF de Estados Unidos

The northwestem part of the Iberian Peninsula is of low to moderate magnitude within the seismotectonic context of the Euro-Mediterranean region. However, a significant increase of the seismic activity has taken place since 1995. Several crises occurred in Lugo province, with a main earthquake of magnitude 5,3 in 1997. The poor coverage from permanent stations monitoring the area has traditionally made difficult any rigorous analysis of this activity. Hence, we undertook a detailed study of the local seismicity between 1999 and 2002, based on the deployment of a temporary seismic array. More than 500 local events were collected during this periodo The seismicity is scattered over the NW Iberian Peninsula including the continental platform. The highest concentration of events is located in the Southern and Eastern part of Galicia, decreasing progressively towards the western part of Asturias. The most active seismic focus is located near the epicentre of the 1997 earthquake (SW of Becerreá, Lugo). The detection of a poorly-known 'background seismicity' through all the NW Iberian Peninsula is another important finding of this work. The results allow to differentiate two seismotectonic domains within NW Iberia: the Atlantic and the Cantabrian domains. In the Atlantic one the seismicity seems to be associated mainly to a NNE-SSW fault system. Lower activity has been found in the Cantabrian domain were the active faults are generally NNW-SSE oriented. The most active zone coincides with the limit between these two zones., Este trabajo ha sido realizado en el marco de los proyectos "GASPI" (AMB98-1012-C02-02) y MARCONI (REN2001-1734-C03-02/MAR) Carlos López agradece la financiación aportada por el progrma "Formación de Personal Investigador" del Ministerio de Cienciea y Tecnologia de España.

The Gibraltar arc and associated broad seismogenic zone that includes the southern Iberian Peninsula and northern part of the Morocco, hosts the convergent boundary between the European and African Plates. The area is characterized by low to moderate magnitude shallow earthquakes, although large historical events have also occurred. The crustal deformation is reflected by the topographic features. Characteristic topographic features are the Beticorogen in Iberia and in Morocco the Atlas Mountains and the Rif Cordillera. The latter two orogenic belts are the response of different geodynamic processes acting at lithospheric scale caused by the complex plate interaction. The zone delineates an arcuate arc system known as the Gibraltar arc limiting to the west Alboran basin. The area is characterized by a relatively large amount of earthquake activity at various depths and with broad spectra of focal mechanisms. Within the last decade a large international effort has been devoted to the area. Key multi-seismic projects have been developed that aim to constrain the structure, composition and tectonic scenario from south of the Atlas to the Betics, across the Rif Cordillera and the Alboran basin. The multidisciplinary research program included: natural source (earthquakes) recording with temporal deployments of broad band (BB) instrumentation and, controlled source seismic acquisition experiments where spatially dense recording of wide-angle seismic reflection shot gathers were acquired. The natural source experiments consisted ofa transect from Merzouga across the Gibraltar Arc and into the Iberian Peninsula (until south of Toledo) and, a nearly regular grid of BB instruments. The controlled source data-sets were able to constrain the crustal structure and provide seismic P-wave propagation velocity models from the coast across the Rif and the Atlas. From south to north the crust features a relatively moderate crustal root beneath the Middle Atlas which can reach 40 km clearly differing from the 35 km thickness value observed at both sides of this root. Travel time inversion results position the crustal root just south of the High Atlas defining a thrusted mantle wedge and, also a limited crustal imbrication is suggested in the Middle Atlas. The most surprising feature is a prominent and unexpected crustal root (over 50 km) located beneath the external Rif and identified by both the wide-angle data and receiver function studies. To the east of this feature the crust thins rapidly by 20 km across the Nekkor fault zone, suggested to be related to the sharp change in crustal thickness.

Since the 1970s, the lithospheric structure beneath the Iberian Peninsula and its continental margins has been extensively investigated using deep multichannel seismic reflection and refraction / wide-angle reflection profiling by different international research teams. The revision of the acquisition experiments and the interpretation methods used along those decades allows to get a beautiful insight on the evolution of active seismic methodologies, from the use of a limited number of analog dataloggers interpreted using 1D reflectivity methods, to the deployment of hundreds to thousands of digital equipments along a single profile inverted using ray theory. On the other hand, the compilation of all the available models reveals the seismic properties of the different tectonic domains sampled, which have a great geodynamical diversity. The investigated areas include crustal imbrication in the Pyrenean range, a large and relatively undisturbed Variscan Massif in the center of Iberia and areas of complex and still not completely understood geodynamics in the Alboran crust domain. This results in Moho depths ranging from around 10 km beneath the Atlantic to values exceeding 50 km in some parts of the Pyrenees or the Rif Cordillera. The compilation of the inferred Moho depths along the interpreted profiles has allowed to obtain a Moho depth model which has been extensively used to contrain numerical modeling studies at crustal and lithospheric scales in a key area of the Western Mediterranean.

The most characteristic topographic features of Morocco are the Atlas Mountains and the Rif Coordillera. These two orogenic belts are the response of different geodynamic processes acting at lithospheric scale caused by a unique driver, the collision between two tectonic plates. Both are located within the diffuse plate boundary zone separating Africa and Europe. The boundary zone is characterized by a relatively broad zone of deformation that includes Mountain chains in southern Iberia, the Betics and the Rif cordillera in Morocco. The zone delineates the arcuate arc system of Gribraltar. Within the last decade a large international effort have been devoted to the area mostly leaded by Spanish groups with the collaboration of international research teams (including scientist form Europe and USA). Key multi-seismic projects have been developed that aim to constrain the structure, composition and tectonic scenario from south of the Atlas to the Betics, across the Rif cordillera and the Alboran basin. The multidisciplinary research program includes: natural source (earthquakes) recording with temporal deployments of broad band (BB) instrumentation and, controlled source seismic acquisition experiments where, spatially dense recording of wide-angle seismic reflection shot gathers were acquired. The passive experiments consisted on: a transect from Merzouga across the Gibraltar arc and into the Iberian peninsula (untill south of Toledo); a nearly regular grid of BB which was achieve by multiple deployments of a number of BB. The controlled source datasets were able to constrain the crustal structure and provide seismic P-wave propagation velocity models from the coast across the Rif and the Atlas. Travel-time inversion of the controlled source seismic data across the Atlas constraints a crustal root to the south of the High Atlas, and reveals mantle wedge. A limited crustal imbrication also appears in the Middle Atlas. The crustal thickness, does not exceeded 40 km in the root zone and is less than 35 km elsewhere. Approaching the Rif, the controlled source data reveals a prominent crustal root over 50 km depth which is located where the topography does not exceed 1400 m. These features indicate that complex structure and processes beneath the crust play a key role in supporting the particular geometry of the surface topography of this part of the western Mediterranean. On one hand the Atlas is being supported by the mantle, on the other the abrupt change in crustal thickness at the Nekkor fault and the deep Rif crustal root can be attributed to interaction of the subducting Alboran slab with the North African Neo-Tethys passive margin.

The Rif cordillera forms, together with the Betic ranges, one of the tightest orogenic arcs on Earth. This continental boundary zone is dominated now by the slow convergence between Nubia and Eurasia, but with clear evidences of extensional tectonics. One of the missing elements to constrain the complex geodynamics of the Gibraltar Arc System is the knowledge of the crustal architecture beneath northern Morocco. In the last decade a major effort has been done in this sense, from active and passive seismics. We compile here the recent results available from the Rif domains. Two 330 km long wide angle DSS profiles were recorded end of 2011 across the Rif in NS and EW transects within the Rifsis project, complemented by onshore recordings of the Gassis-WestMed marine profiles. At the same period, BB seismic arrays were deployed in the area within Topo-Iberia and Picasso projects, allowing receiver function analyses of crustal depths. The ray-tracing modeling of the Rifsis profiles reveal a large Moho step and an area of crustal thickening both in EW and NS directions, grossly coincident with the Bouguer gravity anomalies. The deployment logistics allowed that all the stations recorded all the shots, thus providing useful offline data. We will use here all available in-line and offline data to provide a map of the crustal thickness in northern Morocco. We combined two approaches: i) a hyperbolic time reduction applied to the seismic data, resulting in low-fold stacks in which the reflections from the Moho should appear as subhorizontal lines; ii) the arrival times of the observed PmP phases allow, assuming a mean crustal velocity, to assign a midpoint crustal thickness to each lecture. Although some uncertainties may be inherent to those approaches, a large crustal root, reaching more than 50 km, is well documented in the central part of the Rif Cordillera, close to the zone where the Alboran slab may still be attached to the lithosphere. We also compared these results with those from receiver functions recalculated for the Topo-Iberia and Picasso stations, as well as for a new seismic BB array installed in late 2013 to densify the available dataset. The derived crustal depths confirm a deep crustal root beneath the central Rif and a rapid thinning eastward of Nekkor fault, even if some observed differences deserve further analyses.

The knowledge of the anisotropic properties beneath the Iberian Peninsula and Northern Morocco has been dramatically improved since late 2007 with the analysis of the data provided by the dense IberArray broad-band seismic network deployed in the Topo-Iberia project, the increasing number of permanent stations operating in Morocco, Portugal and Spain, and the contribution of smaller scale/higher resolution experiments. The first Topo-Iberia de-ployment in the Betics-Alboran zone has evidenced a spectacular rotation of the fast polarization direction (FPD) along the Gibraltar arc following the curvature of the Rif-Betic chain. This result has been interpreted as an evidence of mantle flow deflected around the high velocity slab beneath the Alboran Sea Arc. Data from the second Topo-Iberia deployment and from additional deployments in the Moroccan Meseta and the western High Atlas have shown a rather uniform N100ºE FPD beneath the Variscan Central Iberian Massif, consistent with global mantle flow models taking into account contributions of surface plate motion, density variations and net lithosphere rotation. The results from the last deployment of the IberArray network presented here cover the northern part of the Iberian Peninsula and also show a rather uniform FPD orientation close to N100ºE, confirming the previous interpretation. However, the degree of anisotropy changes significantly, from delay times values around 0.5 s beneath NW Iberia to values reaching 2.0s in its NE corner. The anisotropic parameters retrieved from single events providing high quality data also show significant differences for stations located in the Variscan units of NW Iberia, suggesting that the region includes multiple anisotropic layers or complex anisotropy systems.

With the wide availability of broad-band sensors and dataloggers equipped with large storage capabilities, a new approach in crustal and lithospheric seismology has become possible. One of the best examples in Europe of such kind of new generation experiments is provided by the Iberarray observatory platform designed in the framework of the TopoIberia. The IberArray seismic pool was composed by 70+ BB stations, covering the study area in 3 deployments with a site-density of 60km x 60km. The data base holds ~300 sites, including the permanent networks in the area. Hence it forms a unique seismic database in Europe that allows for multiple analyses to constrain the complex geodinamics of the Western Mediterranean. The scientific explotation of this large database is still on progress, but the main results are already available and have lead to the publication of an Special Issue devoted to the Iberian Geodynamics in Tectonophysics. We will highlight here some of the results coming from different techniques.The SKS splitting analysis has provided a spectacular image of the rotation of the fast velocity direction along the Gibraltar Arc. In central and northern Iberia, the fast polarization directions are close to EW, consistently with global mantle flow models considering contributions of surface plate motion, density variations and net lithosphere rotation. Those results suggest an asthenospheric origin of the observed anisotropy related to present-day mantle flow. Receiver functions have revealed the crustal thickness variations beneath the Atlas, Rif and southern Iberia, evidencing a relevant crustal root beneath the Rif, in agreement with recent, high-density active seismic experiments. The Variscan Iberian massif shows a flat Moho discontinuity, while the areas reworked in the Alpine orogeny show a slightly thicker crust. Beneath N Iberia, the imbrication of the Iberian and Eurasian crusts results in complex receiver functions. Depths exceeding 45 km are observed along the Pyrenean range, while the crust thins to values of 26-28 km close to the Atlantic coasts. It is interesting to note that this Moho topography can be compared to the Moho map derived from active seismic profiling, as many deep profile are available on the area. The geometry of the 410-km and 660-km discontinuities has been investigated using novel cross- correlation/stacking techniques, which have revealed significant changes in the transition zone thickness which needs to be explained geodynamically. Ambient noise tomography has allowed to identify the main sedimentary basins and to discriminate between the Variscan and the Alpine reworked areas. Local body-wave tomography in North Morocco has improved the location of the small magnitude events on the area and the details of the crustal structure. Finally, teleseismic tomography has confirmed, using an independent data set, the presence of a high-velocity slab beneath the Gibraltar Arc. It is worthy to note that only the fruitfully collaboration of different research teams from Europe, Africa and North America has made possible to get those results

The Benford’s Law (BL) states that the distribution of first significant digits is not uniform but follows a logarithmic frequency distribution. Even if a remarkable wide range of natural and socioeconomical data sets, from stock market values to quantum phase transitions, fit this peculiar law, the conformity to it has deserved few scientific applications, being used mainly as a test to pinpoint anomalous or fraudulent data. We developed a procedure to detect the arrival of seismic waves based on the degree of conformity of the amplitude values in the raw seismic trace to the BL. The signal is divided in time windows of appropriate length and the fitting of the first digits distribution to BL is checked in each time window using a conformity estimator.We document that both teleseismic and local earthquakes can be clearly identified in this procedure and we compare its performance with respect to the classical STA/LTA approach. Moreover, we show that the conformity of the seismic record to the BL does not depend on the amplitude of the incoming series, as the occurrence of events with very different amplitudes result in quite similar degree of BL fitting. On the other hand, we show that natural or man-made quasi-monochromatic seismic signals, surface wave trains or engine-generated vibrations can be identified through their very low BL estimator values, when appropriate interval lengths are used. Therefore, we conclude that the degree of conformity of a seismic signal with the BL is primarily dependent on the frequency content of that signal.

Topo-Iberia has been a large-scale Spanish project running from 2007 to 2013 that integrated more than 150 researchers on Earth Sciences. One of its key assets was the management of an observatory platform, named IberArray, aimed to provide new geophysical datasets (seismic, GPS, MT) to constrain the structure of Iberia with unprecedented resolution. The IberArray seismic pool was composed by 70+ BB stations, covering the study area in 3 deployments with a site-density of 60km x 60km. The data base holds ~300 sites, including the permanent networks in the area. Hence it forms a unique seismic database in Europe that allows for multiple analyses to constrain the complex geodinamics of the Western Mediterranean. A summary of new results coming from different techniques is presented here. The SKS splitting analysis has provided a spectacular image of the rotation of the fast velocity direction along the Gibraltar Arc. In central and northern Iberia, the fast polarization directions are close to EW, consistently with global mantle flow models considering contributions of surface plate motion, density variations and net lithosphere rotation. Those results suggest an asthenospheric origin of the observed anisotropy related to present-day mantle flow. Receiver functions have revealed the crustal thickness variations beneath the Atlas, Rif and southern Iberia, evidencing a relevant crustal root beneath the Rif, in agreement with recent, high- density active seismic experiments. The Variscan Iberian massif shows a flat Moho discontinuity, while the areas reworked in the Alpine orogeny show a slightly thicker crust. Beneath N Iberia, the imbrication of the Iberian and Eurasian crusts results in complex receiver functions. Depths exceeding 45 km are observed along the Pyrenean range, while the crust thins to values of 26-28 km close to the Atlantic coasts. The geometry of the 410-km and 660-km discontinuities has been investigated using novel cross-correlation/stacking techniques. Ambient noise tomography allows to identify the main sedimentary basins and to discriminate between the Variscan and the Alpine reworked areas. Local body-wave tomography in North Morocco has improved the location of the small magnitude events on the area and the details of the crustal structure. Teleseismic tomography has confirmed, using an independent data set, the presence of a high-velocity slab beneath the Gibraltar Arc.

[EN] An archaeological excavation was carried out on the sites of Pla de Tabac I due to the planned expansion of the rubble landfill site in the municipality of Montoliu de Lleida. Thirty Bronze Age structures (silos, ovens/combustion structures and possible post holes) were excavated., [CA] Amb motiu del projecte d’ampliació del Dipòsit Controlat de Terres i Runes del terme municipal de Montoliu de Lleida, es realitzà una intervenció arqueològica al jaciment del Pla de Tabac I. En aquest jaciment s’excavaren un total de 30 estructures arqueològiques (sitges, forns/estructures de combustió i possibles forats de pal), atribuïbles a un assentament del bronze antic.

Since late 80's a large amount of Deep Seismic Sounding (DSS) transects have been acquired within the microcontinent of Iberia and it margins. This data infrastructure has provided a wealth of knowledge on the strucrure of the crust and lithosphere of the Iberia peninsula, new information on the crustal parameters (Vp, Vs, Poisson's ratio), topography of the Moho discontinuity, the detailed internal architecture of tectonic terranes and orogenic belts, and settled very strong constraints on its geodynamic evolution. The normal incidence seismic imaging effort was initiated by the ESCI program mainly in two key areas. One in the northwestern Iberian to study the crustal structure of the external Variscides, which delineated the geometry of the foreland thrust and fold belt (Cantabrian Zone) and the transition to the hinterland areas (Narcea Antiform area). It revealed high amplitude dipping reflections within the Paleozoic rocks sequences and the flat and ramp geometries of the Cantabrian Zone detachment. The second ESCI Initiative targeted the Betic orogen in order to image the crust belonging to two different crustal domains. The terrane to the north, the crust of the Variscan Iberian Massif and the terrane to the south that corresponded to the Alpine metamorphic complexes of the Betics. These data unveiled the differences between both crustal terranes. In early 2000's and under EUROPROBE's umbrela the most complete transect of the Variscan Orogen was acquired across the SW Ibreria, revealing the anatomy of a transpresive orogen affected by mantle plume during the Carboniferous. The seismic profile samples three major tectonic terranes: the South Portuguese Zone, the Ossa-Morena Zone, and the Central Iberian Zone, which were accreted in Late Paleozoic times. These terranes show a distinctive seismic signature, as do the sutures separating them. The geometry of the sutures appear to be modified by strike slip movements. The upper crust appears to be decoupled from the lower crust suggesting a differences in the distribution of the stress. An unexpected finding was a 1-2 s thick 175 km long high-amplitude conspicuous reflective band a sill-like structure. This was interpreted as an intrusion of mafic magmas in a mid-crustal decollement, a result of the interaction of a mantle plume with an oblique collision/transpression tectonic setting. The data acquired in its margins as part of numerous projects has enrich the knowledge on the ocean continent transition, the lithospheric transition from the Variscan Iberian Massif to the Jurassic oceanic crust, has contained the development of the Valencia trough, has aimed to unravel the complex geodynamics of the Alboran basin. The aim of this work is to revisit the scientific contribution of the high resolution deep seismic sounding to the knowledge of the Iberian Microcontinent and it surroundings.

The westernmost Mediterranean comprises the Iberian Peninsula and Morocco, separated by the Alboran Sea and the Algerian Basin. From north to south this region consists of the Pyrenees, resulting from Iberia-Eurasia collision; the Iberian Massif, which has been undeformed since the end of the Paleozoic; the Central System and Iberian Chain, regions with intracontinental Oligocene-Miocene deformation; the Gibraltar Arc (Betics, Rif and Alboran terranes), resulting from post-Oligocene subduction roll-back; and the Atlas Mountains. We analyzed data from recent broad-band array deployments and permanent stations in the area (IberArray and Siberia arrays, the PICASSO array, the University of Munster array, and the Spanish, Portuguese and Moroccan National Networks) to characterize its lithospheric structure. The combined array of 350 stations has an average interstation spacing of ~60 km. We calculated the Rayleigh waves phase velocities from ambient noise (periods 4 to 40 s) and teleseismic events (periods 20 to 167 s). We inverted the phase velocities to obtain a shear velocity model for the lithosphere to ~200 km depth. Our results correlate well with the surface expression of the main structural units with higher crustal velocity for the Iberian Massif than for the Alpine Iberia and Atlas Mountains. The Gibraltar Arc has lower crustal shear velocities than the regional average at all crustal depths. It also shows an arc shaped anomaly with high upper mantle velocities (>4.6 km/s) at shallow depths (

Topo-Iberia has been a large-scale Spanish project running from 2007 to 2013 that integrated more than 150 researchers on Earth Sciences. One of its key assets was the management of an observatory platform, named IberArray, aimed to provide new geophysical datasets (seismic, GPS, MT) to constrain the structure of Iberia with unprecedented resolution. The IberArray seismic pool was composed by 70+ BB stations, covering the study area in 3 deployments with a site-density of 60km x 60km. The data base holds ~300 sites, including the permanent networks in the area. Hence it forms a unique seismic database in Europe that allow for multiple analyses to constrain the complex geodinamics of the Western Mediterranean. A summary of new results coming from different techniques is presented here. The SKS splitting analysis has provided a spectacular image of the rotation of the fast velocity direction along the Gibraltar Arc. In central and northern Iberia, the fast polarization directions are close to EW, consistently with global mantle flow models considering contributions of surface plate motion, density variations and net lithosphere rotation. Those results suggest an asthenospheric origin of the observed anisotropy related to present-day mantle flow. Receiver functions have revealed the crustal thickness variations beneath the Rif and southern Iberia, including a crustal root beneath the Rif. The Variscan Iberian massif shows a flat Moho discontinuity, while the areas reworked in the Alpine orogeny show a slightly thicker crust. Beneath N Iberia, the imbrication of the Iberian and Eurasian crusts results in complex receiver functions. Depths exceeding 45 km are observed along the Pyrenean range, while the crust thins to values of 26-28 km close to the Atlantic coasts. The geometry of the 410-km and 660- km discontinuities has been investigated using novel cross-correlation/stacking techniques. Ambient noise tomography allows to identify the main sedimentary basins and to discriminate between the Variscan and the Alpine reworked areas. Local body-wave tomography in North Morocco has improved the location of the small magnitude events on the area and the details of the crustal structure. Teleseismic tomography has confirmed, using an independent data set, the presence of a high-velocity slab beneath the Gibraltar Arc.

The Benford's Law (BL) states that the distribution of first significant digits is not uniform but follows a logarithmic frequency distribution. Even if a remarkable wide range of natural and socioeconomical data sets, from stock market values to quantum phase transitions, fit this peculiar law, the conformity to it has deserved few scientific applications, being used mainly as a test to pinpoint anomalous or fraudulent data. We developed a procedure to detect the arrival of seismic waves based on the degree of conformity of the amplitude values in the raw seismic trace to the BL. The signal is divided in time windows of appropriate length and the fitting of the first digits distribution to BL is checked in each time window using a conformity estimator. We document that both teleseismic and local earthquakes can be clearly identified in this procedure and we compare its performance with respect to the classical STA/LTA approach. Moreover, we show that the conformity of the seismic record to the BL does not depend on the amplitude of the incoming series, as the occurrence of events with very different amplitudes result in quite similar degree of BL fitting. On the other hand, we show that natural or man-made quasi-monochromatic seismic signals, surface wave trains or engine-generated vibrations can be identified through their very low BL estimator values, when appropriate interval lengths are used. Therefore, we document that the degree of conformity of a seismic signal with the BL is primarily dependent on the frequency content of that signal.