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We exploit the data from five seismic transects deployed across the Pyrenees to characterize the deep architecture of this collisional orogen. We map the main seismic interfaces beneath each transect by depth migration of P-to-S converted phases. The migrated sections, combined with the results of recent tomographic studies and with maps of Bouguer and isostatic anomalies, provide a coherent crustal-scale picture of the belt. In the Western Pyrenees, beneath the North Pyrenean Zone, a continuous band of high density/velocity material is found at a very shallow level (~10 km) beneath the Mauleon basin and near Saint-Gaudens. In the Western Pyrenees, we also find evidence for northward continental subduction of Iberian crust, down to 50–70 km depth. In the Eastern Pyrenees, these main structural features are not observed. The boundary between these two domains is near longitude 1.3 °E, where geological field studies document a major change in the structure of the Cretaceous rift system, and possibly a shift of its polarity, suggesting that the deep orogenic architecture of the Pyrenees is largely controlled by structural inheritance. The PYROPE (Pyrenean Observational Portable Experiment) project was supported by the Agence Nationale de la Recherche (ANR) Blanc Programme (project PYROPE, ANR-09- BLAN-0229). We also acknowledge SISMOB, the French seismic mobile pool (a component of the RESIF consortium - http://seismology.resif.fr), for providing us with the seismological instrumentation for the temporary deployments. Field work has been also partially funded by the Spanish Ministry of Economy and Competitiveness through Project MISTERIOS (CGL2013-48601-C2-2-R). Peer reviewed

During the last decades, the availability of Synthetic Aperture Radar (SAR) satellite missions, such as the ERS-1/2 and ENVISAT ones operating at C-band who have worked since 1992 to 2011, as well as the X-band COSMOSkyMed and TerraSAR-X constellations, up to the brand new Sentinel-1 mission, have strongly contributed to SAR data diffusion and popularity in the generation of different studies at different scales and in different research fields. One of the most popular SAR technique is the one referred to as Differential SAR Interferometry (DInSAR), which allows measuring with centimeter accuracy the Earth's surface deformation entity related to both natural and man-made hazards. Nowadays, with the increasing of SAR data availability provided by Sentinel-1 constellation of Copernicus European Program, which is composed by two twin satellites operating in C-band since 2014 and 2016, with a repeat pass of 6 days and with a global (i.e. worldwide) data acquisition policy, the SAR EO scenario is becoming more and more operational, thus mainly providing support for natural hazards monitoring. This allows, in theory, and disposing of sufficient computing power, the EO community to monitor, for instance, the deformation of every volcano or to obtain co-seismic displacement maps in a short time frame and anywhere in the world. Accordingly, in this work, we present a fully automatic and fast processing service for the generation of co-seismic displacement maps by using Sentinel-1 data. The implemented system is completely unsupervised and is triggered by the all significant (i.e. larger than a defined magnitude) seismic event registered by the online catalog as those provided by the United States Geological Survey (USGS) and the National Institute of Geophysics and Volcanology of Italy (INGV). The service has been specifically designed to operate for Civil Protection purposes. The generated DInSAR measurements are made available to the geoscience community through the EPOS Research Infrastructure and they will contribute to the creation of a global database of co-seismic displacement maps. Finally, it is worth noting that the developed system relies on widely common IT methods and protocols and is not specifically tied to a defined computing architecture, thus implying its portability, in view also of the European Commission Data and Information Access Services (DIAS) where satellite data (mainly Sentinel) and processing facilities are co-located to reduce the data transfer time during their processing.

Virtual Research Environments (VREs), also known as science gateways or virtual laboratories, assist researchers in data science by integrating tools for data discovery, data retrieval, workflow management and researcher collaboration, often coupled with a specific computing infrastructure. Recently, the push for better open data science has led to the creation of a variety of dedicated research infrastructures (RIs) that gather data and provide services to different research communities, all of which can be used independently of any specific VRE. There is therefore a need for generic VREs that can be coupled with the resources of many different RIs simultaneously, easily customised to the needs of specific communities. The resource metadata produced by these RIs rarely all adhere to any one standard or vocabulary however, making it difficult to search and discover resources independently of their providers without some translation into a common framework. Cross-RI search can be expedited by using mapping services that harvest RI-published metadata to build unified resource catalogues, but the development and operation of such services pose a number of challenges. In this paper, we discuss some of these challenges and look specifically at the VRE4EIC Metadata Portal, which uses X3ML mappings to build a single catalogue for describing data products and other resources provided by multiple RIs. The Metadata Portal was built in accordance to the e-VRE Reference Architecture, a microservice-based architecture for generic modular VREs, and uses the CERIF standard to structure its catalogued metadata. We consider the extent to which it addresses the challenges of cross-RI search, particularly in the environmental and earth science domain, and how it can be further augmented, for example to take advantage of linked vocabularies to provide more intelligent semantic search across multiple domains of discourse.

AbstractThe ability to predict the magnitude of an earthquake caused by deep fluid injections is an important factor for assessing the safety of the reservoir storage and the seismic hazard. Here, we propose a new approach to evaluate the seismic energy released during fluid injection by integrating injection parameters, induced aseismic deformation, and the distance of earthquake sources from injection. We use data from ten injection experiments performed at a decameter scale into fault zones in limestone and shale formations. We observe that the seismic energy and the hydraulic energy similarly depend on the injected fluid volume (V), as they both scale as V3/2. They show, however, a large discrepancy, partly related to a large aseismic deformation. Therefore, to accurately predict the released seismic energy, aseismic deformation should be considered in the budget through the residual deformation measured at the injection. Alternatively, the minimal hypocentral distance from injection points and the critical fluid pressure for fault reactivation can be used for a better prediction of the seismic moment in the total compilation of earthquakes observed during these experiments. Complementary to the prediction based only on the injected fluid volume, our approach opens the possibility of using alternative monitoring parameters to improve traffic-light protocols for induced earthquakes and the regulation of operational injection activities.

We present an unsupervised and automatic system for volcano deformation monitoring via the Copernicus Sentinel-1 data. The system relies on the Parallel Small BAseline Subset (P-SBAS) approach, permitting us to generate updated displacement time series at every new Sentinel-1 acquisition over a selected area of interest in a fast and accurate way. The service is currently operative to monitor the main active Italian volcanoes in the framework of cooperation with the Italian Department of Civil Protection. The system is potentially extendable to every area on the Earth, thus making it suitable for surface displacement monitoring of a large variety of phenomena. Finally, the obtained results are made available to the scientific community through the EPOS Research Infrastructure.

Ground penetrating radar (GPR) named “Roteg” was used to detect known and unknown passages of Divaska Jama and Trhlovca caves in SW Slovenia. “Roteg’s” main characteristics are an extraordinary high power output (20 MW) and high voltage on antennas (up to 20 kV), which allows penetration more than ten times deeper than common GPRs. During the measurement we used 3-m long antennas (50 MHz) with a central frequency of 50 MHz and we clearly detected the reflections from the depth of 200 m after data processing. During field survey 22 profiles were completed with a total length of 4487.97 m. Pretnerjeva and Žibernova Dvorana chambers in Divaska Jama were well visible on radarograms. New big cavities, which were detected below profiles P18, P21 and P22, are almost all at the same level of 350 – 400 m a.s.l. There is another group of cavities at a level of 420 – 450 m a.s.l., which corresponds to Trhlovca. Both cave groups are separated by the gap which extends in the vertical direction, and probably presents a tectonic zone, which is as well visible on the radarograms. By the use of “Roteg” at the karst surface we were able to detect known caves, new - unknown caves and tectonic zones up to 200 m below the surface. Key words: ground penetrating radar, caves, karst, Divaska Jama, Trhlovca, Slovenia. Dolocitev rovov Divaske jame v JZ smeri za Trhlovco z uporabo zelo mocnega nizkofrekvencnega georadarja Nizkofrekvencni georadar (GPR), imenovan »Roteg«, smo uporabili pri zaznavi znanih in neznanih rovov Divaske jame in Trhlovce v JZ Sloveniji. »Rotegove« glavne znacilnosti so izjemna moc (20 MW) in visoka napetost do 20 kV na antenah, kar omogoca penetracijo, ki je vec kot desetkrat globlja, kot jo dosežejo obicajni georadarji. Med meritvami smo uporabili 3 m dolgi anteni (50 MHz) s srediscno frekvenco 50 MHz. Tako smo po obdelavi podatkov jasno zaznali odboje iz globine 200 m. Med terenskimi meritvami smo izmerili 22 profilov s skupno dolžino 4490 m. Pretnerjeva in Žibernova dvorana v Divaski jami sta bili dobro vidni na georadarskih profilih. Nove velike jame, ki smo jih zaznali pod profili P18, P21 in P22, so skoraj vse na istem nivoju, 350–400 m nad morjem. Druga skupina jam na nadmorski visini 420–450 m ustreza Trhlovci. Obe skupini jam sta loceni z vrzeljo v navpicni smeri, ki je verjetno tektonska cona in je dobro vidna na georadarskih profilih. Z uporabo »Rotega« na kraskem povrsju smo dolocili znane jame, nove neznane jame in tektonske cone do globine 200 m pod povrsjem. Kljucne besede: georadar (GPR), jame, kras, Divaska jama, Trhlovca, Slovenija.

International audience; The availability of GPS survey data spanning 22 years, along with several independent velocity solutions including up to 16 years of permanent GPS data, presents a unique opportunity to search for persistent (and thus reliable) deformation patterns in the Western Alps, which in turn allow a reinterpretation of the active tectonics of this region. While GPS velocities are still too uncertain to be interpreted on an individual basis, the analysis of range-perpendicular GPS velocity profiles clearly highlights zones of extension in the center of the belt (15.3 to 3.1 nanostrain/year from north to south), with shortening in the forelands. The contrasting geodetic deformation pattern is coherent with earthquake focal mechanisms and related strain/stress patterns over the entire Western Alps. The GPS results finally provide a reliable and robust quantification of the regional strain rates. The observed vertical motions of 2.0 to 0.5 mm/year of uplift from north to south in the core of the Western Alps is interpreted to result from buoyancy forces related to postglacial rebound, erosional unloading, and/or viscosity anomalies in the crustal and lithospheric root. Spatial decorrelation between vertical and horizontal (seismicity related) deformation calls for a combination of processes to explain the complex present-day dynamics of the Western Alps.

Abstract We use new analogue modelling experiments to analyse the development of pull-apart basins in an upper crust characterised by the presence of pre-existing discrete fabrics. As in previous models, lateral movement of rigid basal plates induced strike-slip deformation of a sand-pack. Local extension allowing the formation of a pull-apart basin was produced by the step-over geometry of the master faults; in this area, a basal silicone layer was introduced to distribute deformation and reproduced a weaker crust in the basin. Conditions of neutral, overlapping and underlapping interacting master faults were reproduced. The model upper crust, modelled by a sand mixture, was characterised by the presence of pre-existing structures; the orientation of these inherited heterogeneities was systematically varied in different experiments. Model results indicate that, depending on their orientation with respect to the strike-slip displacement, pre-existing structures can be reactivated both within and at the margins of the pull-apart basins. Inside the basin, reactivation occurs when the pre-existing structures are orthogonal or sub-orthogonal to the strike-slip displacement; in this case, the pre-existing fabrics delay the development and linkage of cross-basin faults and increase the complexity of the deformation pattern giving rise to a new set of faults characterised by an atypical trend. Pre-existing fabrics oblique to the local extension direction may be partly reactivated in the central part of the basin as segments of cross-basin faults. At the margins of the pull-apart, reactivation occurs if the fabrics spatially coincide with the lateral boundaries of the silicone layer. In these conditions, reactivation allows a faster development of the border faults, which are less segmented than in the homogenous models; this also results in a more regular final geometry of the pull-apart.

The large and continuous availability of Sentinel-1 satellite data is a key factor for developing operational monitoring services at both local and global scale. In this work we present a national scale DInSAR analysis of the Italian territory. To this aim we exploit the Parallel Small BAseline Subset (P-SBAS) approach that allows us to generate large spatial scale deformation maps and corresponding displacement time series in an efficient, automatic and systematic way. Achieved results demonstrate the high capability of Sentinel-1 and DInSAR technique to become effective tools for monitoring the ground displacements at wide spatial scale, with important implications in risk management and mitigation.