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[EN] Web platforms and cloud computing are revolutionizing the remote sensing methodologies and improve significantly the capacity to analyze the Earth surface. Here, we present the Geohazard Exploitation Platform (GEP) of the European Space Agency (ESA) and, particularly, an application of the P-SBAS service of this platform on the Lisbon metropolitan area. The analysis was developed as part of the project RISKCOAST that deals with coastal hazards, seeking to test diverse methodologies to monitor them. The region of Lisbon is a pilot area of this project because different surficial and coastal processes impact it. To analyze this region, we generated through GEP a deformation map over 3,000 km2 of the Portuguese coast where 2.8 million people live. Thanks to GEP we generated the map in only 24h. This deformation map serves us to recognize several places with ground instability problems. The main processes identified associated to those unstable terrains were landfill and sediment consolidation, active landslides and local subsidence most probably related to groundwater withdrawal. As far as we know, most of the detected deformations were not registered so far. We also detected deformations of unknown origin. Furthermore, we determined that an area previously affected by ground subsidence in the 90’s appears to be currently stable. The mentioned findings show how different processes due to the interaction of human activities and infrastructures with the ground can affect metropolitan areas. In the case of Lisbon metropolitan area, the municipalities can use the obtained information to know and to anticipate future issues regarding building and infrastructure damage. In this sense, this research is an example of how new InSAR technologies such as the modern cloud analytic platforms can serve to identify and monitor surficial processes in an easy way to prevent problems associated to unstable ground., The research was supported by the European Regional Development Fund (ERDF) through the project “RISKCOAST” (SOE3/P4/E0868) of the Interreg SUDOE Programme.

Properly assessing the hazard of landslides begins with mapping and characterising them from a geological perspective. Although landslides have demonstrated a worldwide impact and are the second most damaging geohazard in Spain (after floods), there is still little social awareness about them. This fact evidences the necessity of additional efforts for the study of these natural phenomena. The integration of an innovative remote sensing technique, like satellite radar interferometry, with geomorphological and geological methods has demonstrated to be an effective multi-technique approach for landslide research. The present Ph.D. Thesis is developed in this framework and improves the knowledge of landslides by applying such combination of methodologies. Two critical and interesting areas in the Province of Granada (Southern Spain) have been selected for study: the Sierra Nevada Range and the Rules Reservoir. The Sierra Nevada is a high-elevation mountain range where some landslides have been unreported or unnoticed, despite being susceptible to slope movements. In this case, Differential Synthetic Aperture Radar (DInSAR) and Landscape Analysis techniques were integrated to optimise landslide mapping and provide an updated landslide inventory map of the range. The Landscape Analysis was based on the identification of river anomalies by the double normalised channel steepness (ksnn) index, a novel derivation from the conventional normalised steepness index (ksn) that reduced the active tectonics signal of the area. The visual exploration of ksnn anomalies and the unstable ground areas obtained from DInSAR velocity maps evidenced 28 new landslides. This mapping reveals a significant increase of the area affected by landslides (33.5%) compared with the previous inventory from the Geological and Mining Institute of Spain (IGME-CSIC) (14.5%). A relevant finding of this study is the identification, for the first time, in the Sierra Nevada, of two landslide typologies: Deep-Seated Gravitational Slope Deformations (DGSDs) and rockslides. Their diffuse boundaries, homogeneous lithology (schists), and previous glacial morphologies made delimiting these landslides difficult, but the utilised techniques greatly facilitated the process. The geomorphological observations made in the field and the exploration of maps (e.g. slope, hillshade, aspect, rugosity) derived from high-resolution Digital Elevation Models (DEMs) were fundamental procedures for accurately defining the landslides’ boundaries, as well as to describe landslide-related morphologies. Due to the large size and typology of these landslides, attempts were made to provide a first insight about their hazard and potential impacts in the region. The Rules Reservoir is one of the most strategic infrastructures in the Province of Granada, with well-known slope instability problems during and after its construction. In this case, DInSAR techniques were applied in the reservoir’s slopes to derive ground velocity maps that revealed three active landslides. The thorough geomorphological investigation, based on field observations and photo-interpretation of historical aerial images, allowed to distinguish between rotational (Lorenzo-1 and Rules Viaduct landslides) and translational (El Arrecife Landslide) landslide typologies, as well as to identify surficial damages related to their activity. The DInSAR-derived times series of accumulated displacement (TSs) revealed a correlation between the acceleration of the rotational landslides’ movement and drawdowns of the reservoir water level. Due to their dimensions, rotational character and minor accelerations, a rapid slope failure and sudden collapse into the reservoir is not expected from the Lorenzo-1 and Rules Viaduct landslides. However, they pose a risk to nearby infrastructures due to the retrogressive evolution of these landslides: the Lorenzo-1 Landslide is already affecting the N-323 National Road, while the Rules Viaduct Landslide may be provoking deformation on the southern sector of the Rules Viaduct (A-44 Highway). Regarding the El Arrecife Landslide, its translational character implies a greater potential hazard and further efforts were made to characterise this landslide. The El Arrecife Landslide is located in the western slope of the Rules Reservoir and it was identified by using DInSAR data, as the poorly defined boundaries of the landslide made its recognition in the landscape challenging. This landslide was analysed by a multitechnique approach to provide a rapid characterisation and comprehensive understanding of its structure, volume and historical activity. The structural field surveys enabled the identification of many foliation orientations of the rocks (phyllites) and a kinematic analysis revealed the most probable orientation to cause a planar slope failure. The estimated location of the surface of rupture allowed determining the extremely large volume of the landslide (14.7 million m3). The short-term activity of the landslide (last 5 years) was evidenced by DInSAR, while geophysical data based on Ground Penetrating Radar (GPR) data revealed its medium-term activity (last 22 years). Both techniques evidenced a vertical movement of the landslide around 2 cm/yr. Photogrammetric techniques based on the Structure-for-Motion (SfM) method were also applied, but no rapid shallow movements were detected during the analysed period (14 years). Besides having an overall translational movement, the landslide’s foot is composed by smallersize rotational landslides. The DInSAR TSs indicated that variations in the reservoir water level do not affect the overall landslide body, but drawdowns of the water level do accelerate the movement of these rotational slides. Therefore, the most significant hazard of the El Arrecife Landslide is related to such rotational slides, that have been causing damage to the N-323 National Road for several decades and are expected to persist. Although improbable, the possibility of a rapid and sudden acceleration of the entire landslide and subsequent collapse into the reservoir cannot be underestimated, given its translational kinematics and large size. It is therefore crucial to consider the response of this landslide to possible hazardous scenarios derived from extraordinary events, such as drastic reservoir water level drawdowns, intense precipitation, or an earthquake., La cartografía y caracterización geológica de los movimientos de ladera son el primer paso para la evaluación de su peligrosidad. A pesar del impacto que generan a nivel mundial y de ser el segundo peligro geológico más dañino en España (después de las inundaciones), todavía existe poca concienciación social sobre los movimientos de ladera. Este hecho evidencia la necesidad de realizar esfuerzos adicionales para el estudio de estos fenómenos naturales. La aplicación de un enfoque multi-técnica que combine métodos innovadores de teledetección, como la interferometría de satélite radar, con métodos geomorfológicos y geológicos ya ha demostrado ser muy eficaz para la investigación de movimientos de ladera. La presente Tesis Doctoral se desarrolla en este marco y mejora el conocimiento de los movimientos de ladera aplicando dicha combinación de técnicas. El estudio de esta tesis se ha focalizado en zonas críticas y de interés de la Provincia de Granada (Sur de España): Sierra Nevada y el Embalse de Rules. Sierra Nevada es una cadena montañosa de gran altitud, en la que algunos movimientos de ladera no han sido identificados, a pesar de ser susceptible a ellos. En este caso, se integraron técnicas de Interferometría Diferencial de Radar de Apertura Sintética (DInSAR) y de Análisis del Relieve para optimizar la cartografía de movimientos de ladera y proporcionar un inventario actualizado de estos. El Análisis del Relieve se basó en la identificación de anomalías en ríos, utilizando el índice de pendiente doble normalizada (ksnn), una novedosa derivación del índice de pendiente normalizada convencional (ksn), mediante el cual se redujo la influencia de la tectónica activa de la zona. Así, se detectaron 28 nuevos movimientos de ladera mediante la visualización de anomalías del índice ksnn y de las zonas inestables del terreno obtenidas de los mapas de velocidad DInSAR. La nueva cartografía revela un aumento significativo de la superficie afectada por movimientos de ladera (33.5%) en comparación con el inventario anterior del Instituto Geológico y Minero de España (IGME-CSIC) (14.5%). Otro hallazgo importante ha sido la identificación, por primera vez en Sierra Nevada, de dos tipos de movimientos de ladera: Deformaciones Gravitacionales Profundas de Ladera (DGSDs) y deslizamientos en roca. Los límites difusos, la litología homogénea (esquistos) y las morfologías glaciares dificultaron la delimitación de estos movimientos, pero las técnicas utilizadas facilitaron enormemente el proceso. Las observaciones geomorfológicas realizadas en campo y la exploración de mapas (p. ej. pendiente, sombreado, orientación, rugosidad) derivados de Modelos Digitales de Elevación (DEMs) de alta resolución fueron fundamentales para definir con precisión los límites de los movimientos de ladera, así como para describir sus morfologías. Debido al gran tamaño y a la tipología de estos movimientos, se ha proporcionado una visión preliminar sobre su peligrosidad y posible impacto en la región. El Embalse de Rules es una de las infraestructuras más estratégicas de la Provincia de Granada y bien conocido por los problemas de inestabilidad del terreno que ocurrieron durante y después de su construcción. En este caso, se aplicaron técnicas DInSAR en las laderas del embalse para obtener mapas de velocidad del terreno, que revelaron la existencia de tres deslizamientos activos. La exhaustiva investigación geomorfológica basada en observaciones de campo y fotointerpretación de imágenes aéreas históricas, permitió distinguir entre dos tipologías de deslizamientos: rotacionales (Lorenzo-1 y Viaducto de Rules) y traslacionales (El Arrecife), así como identificar daños superficiales relacionados con la actividad de estos. Las series temporales de desplazamiento acumulado (TSs) derivadas de DInSAR revelaron una correlación entre la aceleración del movimiento de los deslizamientos rotacionales y los descensos del nivel de agua del embalse. Las dimensiones, el carácter rotacional y las leves aceleraciones de estos deslizamientos, hacen que sea poco probable que se produzca un colapso repentino y rápido de las laderas en el embalse. Sin embargo, estos suponen un riesgo para las infraestructuras cercanas por su evolución retrogresiva: el Deslizamiento Lorenzo-1 ya está afectando a la Carretera Nacional N-323, mientras que el Deslizamiento del Viaducto de Rules puede estar deformando el tramo sur del Viaducto de Rules (Autovía A-44). En cuanto al Deslizamiento de El Arrecife, su carácter traslacional lo hace potencialmente más peligroso, lo cual ha motivado realizar una caracterización más detallada del mismo. El Deslizamiento de El Arrecife está situado en la ladera occidental del Embalse de Rules y se identificó gracias a los datos DInSAR, ya que sus límites poco definidos dificultaron su reconocimiento en el paisaje. Este deslizamiento ha sido analizado mediante un enfoque multi-técnica para elaborar una caracterización rápida y una comprensión exhaustiva de su estructura, volumen y actividad histórica. Mediante el trabajo de campo estructural, se pudieron identificar varias orientaciones de la foliación de las rocas (filitas), y se obtuvo la orientación más probable para generar una rotura planar de la ladera mediante un análisis cinemático. También se estimó la estimación de la superficie de rotura, determinando así el volumen extremadamente grande del deslizamiento (14.7 millones de m3). Los datos DInSAR mostraron la actividad a corto plazo del deslizamiento (5 años), mientras que los datos geofísicos obtenidos de Radar de Penetración Terrestre (GPR) revelaron su actividad a medio plazo (últimos 22 años). Con ambas técnicas se obtuvo un movimiento vertical del deslizamiento de alrededor de 2 cm/año. También se aplicaron técnicas fotogramétricas basadas en el método ‘Structurefor- Motion’ (SfM), pero no se detectaron movimientos rápidos superficiales durante el periodo analizado (14 años). Además de su movimiento traslacional general, el pie del deslizamiento está formado por deslizamientos rotacionales de menor tamaño. Las series temporales (TS) derivadas de DInSAR indican que las variaciones en el nivel de agua del embalse no afectan a todo el cuerpo del deslizamiento, pero los descensos del nivel del embalse sí que aceleran el movimiento de los movimientos rotacionales del pie. Por lo tanto, el peligro más significativo del deslizamiento de El Arrecife está relacionado con estos deslizamientos rotacionales, que ya han estado generando daños en la Carretera Nacional N-323 durante varias décadas y se espera que persistan. Aunque es improbable, la posibilidad de una aceleración rápida y repentina de todo el deslizamiento y su posterior colapso en el embalse no debe descartarse, debido a su cinemática traslacional y tamaño. Por lo tanto, es de vital importancia considerar la respuesta de este deslizamiento ante posibles escenarios peligrosos derivados de acontecimientos extraordinarios, tales como una reducción drástica del nivel de agua del embalse, precipitaciones intensas o un terremoto., Tesis Univ. Granada., B-RNM-305-UGR18, A-RNM-508- UGR20, and P18-RT-3632 (‘RADANDALUS’) from the European Regional Development Fund (ERDF)/Junta de Andalucía-Consejería de Transformación Económica, Industria, Conocimiento y Universidades, The ERDF through the project ‘RISKCOAST’ (SOE3/P4/E0868) of the Interreg SUDOE Programme and the project ‘MORPHOMED’ (PID2019-107138RB-I00) from the Spanish Ministry of Science (MCIN)/State Research Agency (SRA). The work of Jorge Pedro Galve was also funded by the ‘Ramón y Cajal’ Programme (RYC-2017-23335) of the Spanish Ministry of Science, Access to the Geohazard Exploitation Platform (GEP) of the European Space Agency (ESA) was provided by the NoR Projects Sponsorship (Project ID: 63737)

[EN] Within the framework of the IGME-CSIC Department of Geological Hazards and Climate Change, the OBTIER research group was created in July 2021 and currently has 22 members, including scientific and technical staff, as well as young people with contracts linked to competitive national and international research projects. The main objective of the group is to provide society with scientific information, methods, tools and solutions to mitigate the impact of geohazards and the effects of Climate Change. OBTIER is currently leading 6 competitive projects (4 European and 2 national), as well as several projects in agreement with other national and international administrations. It is an active member of the EuroGeoSurveys Earth Observation Expert Group and the ASGMI Geological Hazards Group. OBTIER offers society a wide range of capabilities on: earthquakes, tsunamis, landslides, land subsidence, volcanic eruptions, droughts and floods. In 2021, the group published an article in Science entitled: Mapping the global threat of land subsidence with significant media coverage around the world.

[EN] The SAR Interferometry techniques, Persistent Scatterer Interferometry (PSI) among them, are nowadays known as important tools for monitoring Earth surface movements. Several regional and national Ground Motion Services based on PSI already exist. Moreover, since 2022 the European Ground Motion Service will be operational and will annually provide an updated displacement map over the whole Europe. This will suppose a big amount of ground displacement measurements along the European territory. For each measurement EGMS will provide the annual velocity and the time series of deformation covering the period 2014 to one year prior to each delivery. In this context, it will be more and more necessary having tools to ease the management, analysis, and interpretation, of those wide areas and huge amount of data. We present here a first step in this direction: the ADATools are a set of tools to automatically have secondary, and more operational, products derived from a PSI map. Starting from a fast extraction of the most significant Active Deformation Areas (ADA), with the ADAFinder tool, then we can have a preliminary classification of the most probable phenomena (landslides, subsidence, settlements, or sinkholes) that is behind the detected movement, with the ADAClassifier tool. Moreover, LOS2hv tool allows to derive the horizontal (east-west) and vertical components of the movement in case we have maps of ascending and descending geometries. Finally, it is presented a product that analyzes the local displacement gradients to generate potential damage maps in urban areas. The tools will be presented thorough some results obtained on an area of the Granada County with the use of Sentinel-1 data. All the results have been achieved within the framework of the Riskcoast Project (financed by the Interreg Sudoe Program through the European Regional Development Fund, ERDF)., This work was mainly supported by the European Regional Development Fund (ERDF) through the project “RISKCOAST” (SOE3/P4/E0868) of the Interreg SUDOE Programme.

The InSAR technique has been proved to be a powerful tool in order to detect, monitoring and analyse movements related to geological phenomena. Its application ranges from regional/national scale to a very detailed scale, up to a single building analysis. Moreover, since 2014, the free and constant availability of Sentinel-1 data has been helping the tendency of using more and more this technique in the institutional risk management activities. Many European and national projects have been financed in order to investigate and improve the processing performances and broaden the operational use and application of the results. In this work, we present the first results developed in the framework of the project Riskcoast (SOE3/P4/E0868) over an area of around 4 km 2 in Andalucía (Spain), including the city and the coast of Granada. Riskcoast has been funded by the Interreg Sudoe Programme through the European Regional Development Fund (ERDF). The presented work is as an example of multi scale (medium to large) application of InSAR for geohazard applications. The velocity map including the estimation of the displacement time series have been produced over the whole area by processing 139 radar images of the Sentinel-1 (A and B). Starting from those results a rapid and semi-automatic extraction of the most significant active displacement areas (ADA) has been performed. Then, after a classification of the detected areas, a more detailed analysis has been done over some selected costal landslides. Over those landslides a damage mapping has been generated based on field surveys, and then analysed together with the spatial gradient of displacement derived by the InSAR results. The Riskcoast project will be introduced and the first results presented. Powered by TCPDF

The European Space Agency’s Geohazard Exploitation Platform (GEP) (https://geohazardstep.eu/#!) is a web-based platform through users can perform independent analysis by exploiting satellite data. This platform hosts several thematic apps that allow to identify, monitor and asses hazard related to geological processes such as volcanism, land subsidence or landslides. The Sentinel-1 CNR-IREA SBAS service is one of these thematic apps that consists on a Differential SAR Interferometry (DInSAR) processing chain for the generation of Earth deformation time series and mean velocity maps of surface ground displacement. In the last decades, DInSAR techniques have proved to be powerful tools to detect and monitor active processes related to geological ground instability issues. In this context, the Sentinel-1 GEP service seems to be a promising way to perform independent and high temporal resolution DInSAR analysis from any part of the world in just 24 hours.

The Rules Reservoir is located in the Guadalfeo River to the south of Sierra Nevada (Betic Chain, SE Spain). This reservoir has a storage capacity of 117 hm3 and it supplies water to the populations, subtropical crops and greenhouses in the coast of Granada. The construction of the reservoir presented difficulties due to the instability of the substrate. Such instability is still active and it has been evidenced by several studies but not in great detail. We have analysed the area by means of InSAR techniques to confirm the existence of ground displacement due to landsliding. We produced a surface velocity map and displacement time series in the reservoir surrounding slopes by processing 139 radar images of the Sentinel-1 (A and B) satellite on ascending orbits from 10 March 2015 to 20 September 2018. A methodology developed in the CTTC (Centre Tecnològic de Telecomunicacions de Catalunya) was used to process the images and measure the surface displacements., NO ACK.

EGU General Assembly 2019, Vienna (Austria) 7-12 April 2019

El graben asimétrico de Albuñuelas se localiza en el extremo sureste de la cuenca intramontañosa de Granada. Su estructura se define por un sistema de fallas normales E-O que hunden el bloque de depósitos sedimentarios neógenos y que intersectan con un sistema de pliegues asimétricos vergentes al norte. Los rasgos estructurales observados permiten reconstruir la evolución del graben asimétrico y vincularla a la evolución geológica regional de la Cordillera Bética. Los datos interpretados de los perfiles de los ríos y de los sedimentos recientes cerca de la falla principal sur (Falla de Albuñuelas) sugieren revisar su actividad The Albuñuelas asymmetric graben is located in the southeastern end of the Granada intramontane basin. Its structure is defined by a conjugate system of E-W normal faults that down-drop the Neogene sedimentary deposits and cross-out a system of north-vergent asymmetric folds. The observed structural features allow the reconstruction of the asymmetric graben evolution and its linkage to the regional geologic evolution of the Betic Chain. The interpreted data from the river profiles and the recent sediments related to the main southern fault (Albuñuelas Fault) suggest the need of revision of its activity

El graben asimétrico de Albuñuelas se localiza en el extremo sureste de la cuenca intramontañosa de Granada. Su estructura se define por un sistema de fallas normales E-O que hunden el bloque de depósitos sedimentarios neógenos y que intersectan con un sistema de pliegues asimétricos vergentes al norte. Los rasgos estructurales observados permiten reconstruir la evolución del graben asimétrico y vincularla a la evolución geológica regional de la Cordillera Bética. Los datos interpretados de los perfiles de los ríos y de los sedimentos recientes cerca de la falla principal sur (Falla de Albuñuelas) sugieren revisar su actividad, The Albuñuelas asymmetric graben is located in the southeastern end of the Granada intramontane basin. Its structure is defined by a conjugate system of E-W normal faults that down-drop the Neogene sedimentary deposits and cross-out a system of north-vergent asymmetric folds. The observed structural features allow the reconstruction of the asymmetric graben evolution and its linkage to the regional geologic evolution of the Betic Chain. The interpreted data from the river profiles and the recent sediments related to the main southern fault (Albuñuelas Fault) suggest the need of revision of its activity