Points and areas prone to earthquake-induced landslides in the CARM. Base information for Civil Protection

Se presenta un trabajo de aplicación para la definición de posibles escenarios de catástrofe sísmica, donde deben de incorporarse los movimientos de ladera, como información de base para la última revisión del Plan Especial de Protección Civil ante el Riesgo Sísmico en la Región de Murcia (SISMIMUR). Para ello se ha confeccionado un inventario adecuado y un mapa a escala 1:200.000 que contiene los puntos y zonas más susceptibles a este tipo de fenómenos inducidos por los terremotos en la CARM que pueden afectar a núcleos urbanos, infraestructuras lineales (carreteras y ferrocarriles), balsas mineras, cursos de agua y cuerpos de agua (embalses y lagos). En el análisis solo se han seleccionado los puntos definidos como desprendimientos s.l., tipología predominante en la zona de estudio y de mayores efectos de cara al escenario de la catástrofe sísmica posible. Aunque en la mayoría de las infraestructuras evaluadas están alejadas de movimientos de ladera inventariados, hay núcleos de población importantes como Lorca, Águilas o Caravaca de la Cruz, entre otras, así como algunos tramos del creciente entramado urbano del litoral murciano con zonas de susceptibilidad alta. El tramo más susceptible sería el situado en la carretera RM-520, entre Archena y Abarán.In this work, we present a methodology to define potential seismic scenarios including seismic-induced landslides as background information for the latest revision of the “Plan Especial de Protección Civil ante el Riesgo Sísmico en la Región de Murcia (SISMIMUR)”. We first made an adequate inventory and a map at 1:200,000 scale containing the points and areas more susceptible to this type of seismic-induced effects in the CARM which may affect urban areas, lifelines(roads and railways), tailing dams, waterways and bodies of water (reservoirs and lakes). For this analysis, only points defined as rockfalls s.l. have been selected, since they are the predominant type of landslide in the area and it is associated to the greatest effects regarding a potential seismic scenario. Although most of the infrastructures evaluated are far from the inventoried landslides, some areas with high susceptibility have been identified near major population centers, such as Lorca, Águilas, Caravaca de la Cruz, etc., and near of some growing urban fabric areas located along the Murcia province coast. According to this study, the most vulnerable section would be located in the RM-520 road between Archena and Abarán

Regional subsidence modelling in Murcia city (SE Spain) using 1-D vertical finite element analysis and 2-D interpolation of ground surface displacements

Subsidence is a hazard that may have natural or anthropogenic origin causing important economic losses. The area of Murcia city (SE Spain) has been affected by subsidence due to groundwater overexploitation since the year 1992. The main observed historical piezometric level declines occurred in the periods 1982–1984, 1992–1995 and 2004–2008 and showed a close correlation with the temporal evolution of ground displacements. Since 2008, the pressure recovery in the aquifer has led to an uplift of the ground surface that has been detected by the extensometers. In the present work an elastic hydro-mechanical finite element code has been used to compute the subsidence time series for 24 geotechnical boreholes, prescribing the measured groundwater table evolution. The achieved results have been compared with the displacements estimated through an advanced DInSAR technique and measured by the extensometers. These spatio-temporal comparisons have showed that, in spite of the limited geomechanical data available, the model has turned out to satisfactorily reproduce the subsidence phenomenon affecting Murcia City. The model will allow the prediction of future induced deformations and the consequences of any piezometric level variation in the study area.This work has been supported by the Spanish Ministry of Economy and Competitiveness and EU FEDER funds under projects ESP2013-47780-C2-2-R and TEC2011-28201-C02-02 and by the project 15224/PI/10 from the Regional Agency of Science and Technology in Murcia. The European Space Agency (ESA) Terrafirma project funded all the SAR data processing with the SPN technique

Exploitation of satellite A-DInSAR time series for detection, characterization and modelling of land subsidence

In the last two decades, advanced differential interferometric synthetic aperture radar (A-DInSAR) techniques have experienced significant developments, which are mainly related to (i) the progress of satellite SAR data acquired by new missions, such as COSMO-SkyMed and ESA’s Sentinel-1 constellations; and (ii) the development of novel processing algorithms. The improvements in A-DInSAR ground deformation time series need appropriate methodologies to analyse extremely large datasets which consist of huge amounts of measuring points and associated deformation histories with high temporal resolution. This work demonstrates A-DInSAR time series exploitation as valuable tool to support different problems in engineering geology such as detection, characterization and modelling of land subsidence mechanisms. The capabilities and suitability of A-DInSAR time series from an end-user point of view are presented and discussed through the analysis carried out for three test sites in Europe: the Oltrepo Pavese (Po Plain in Italy), the Alto Guadalentín (Spain) and the London Basin (United Kingdom). Principal component analysis has been performed for the datasets available for the three case histories, in order to extract the great potential contained in the A-DInSAR time serie

Performance of TerraSAR-X for urban subsidence monitoring: Murcia case study

This paper presents an analysis of the performance of TerraSAR-X for subsidence monitoring in urban areas. The city of Murcia has been selected as a test-site due to its high deformation rate and the set of extensometers deployed along the city that provide validation data. The obtained results have been compared with those obtained from ERS/ENVISAT data belonging to the same period and validated with the in-situ measurements.Postprint (published version

Geometrical and geotechnical characterization of the earth fissures appeared in the Guadalentín Valley (southeastern Spain) after the September 2012 flooding

Two earth fissures appeared in Murcia province (southeastern Spain) after the flood occurred because of a heavy downpour on 28 September 2012. In this area, located within the Guadalentín Valley, up to 212 L m−2 was reported that day. More than 200 agricultural exploitations were destroyed by the flooding, with a devastating effect on many infrastructures, such as a main A-7 highway bridge that collapsed in this event. The earth fissures appeared after this flooding in the towns of Puerto Lumbreras and Totana. The first fissure showed a straight-line direction approximately parallel to the main geological structures of the Guadalentín Valley. The total length of the fissure was 400 m and was 2 to 3 m in depth. The soil in the fissure is classified as a low-plasticity silt with some sand and clay, ML, according to the Unified Soil Classification System. From the sieve and hydrometer tests, the percentage of silt in these samples was between 48 % and 68 %, the clay content between 12 % and 30 % and the sand content between 2 % and 40 %. The plasticity index was smaller than 9.2 for all the samples. To evaluate the piping and internal erosion susceptibility of the soil, pinhole, crumb and geochemical tests were done on the collected samples. A result of non-dispersive soil was obtained from crumb and pinhole tests. Nevertheless, the pH, sodium adsorption ratio and exchangeable sodium percentage tests showed that some samples could be affected by the dispersion of the soil. Also, the collapsible potential of the soil was studied, showing negative results for all the samples except for that collected at the southern end of the fissure, which showed a medium to high potential. Concerning the Totana fissure, it appeared with different branches and holes instead of as a rectilinear pattern. The total length of the fissure was 190 m, with the soil characterized as a silty soil. Lastly, INSAR data, GPS, GPR and land subsidence maps were used to study the possible origin of these fissures.This research has been supported by the Spanish Ministry of Economy and Competitiveness, the State Agency of Research and the European Funds for Regional Development (grant no. TEC2017-85244-C2-1-P), UNESCO (grant no. ICGP641), the Universidad de Alicante (grant no. GRE17-11), and the Universidad de Alicante (grant no. GRE18-15)

Application of multi-sensor advanced DInSAR analysis to severe land subsidence recognition: Alto Guadalentín Basin (Spain)

Multi-sensor advanced DInSAR analyses have been performed and compared with two GPS station measurements, in order to evaluate the land subsidence evolution in a 20-year period, in the Alto Guadalentín Basin where the highest rate of man-induced subsidence (> 10 cm yr−1) of Europe had been detected. The control mechanisms have been examined comparing the advanced DInSAR data with conditioning and triggering factors (i.e. isobaths of Plio-Quaternary deposits, soft soil thickness and piezometric level).This work is financially supported by the DORIS project (Ground Deformation Risk Scenarios: an Advanced Assessment Service) funded by the EC-GMES-FP7 initiative (Grant Agreement 423 no. 242212). ALOS PALSAR images were provided by the project JAXA-1209. Part of this work is supported by the Spanish Government under project TEC2011-28201-C02-02 and TIN2014-55413-C2-2-P and by the project 15224/PI/10 from the Regional Agency of Science and Technology in Murcia. Additional funding was obtained from the Spanish Research Program through the projects AYA2010-17448, ESP2013-47780-C2-1-R and ESP2013-47780-C2-2-Rand by the Ministry of Education, Culture and Sport through the project PRX14/00100

Radar interferometry techniques for the study of ground subsidence phenomena: a review of practical issues through cases in Spain

Subsidence related to multiple natural and human-induced processes affects an increasing number of areas worldwide. Although this phenomenon may involve surface deformation with 3D displacement components, negative vertical movement, either progressive or episodic, tends to dominate. Over the last decades, differential SAR interferometry (DInSAR) has become a very useful remote sensing tool for accurately measuring the spatial and temporal evolution of surface displacements over broad areas. This work discusses the main advantages and limitations of addressing active subsidence phenomena by means of DInSAR techniques from an end-user point of view. Special attention is paid to the spatial and temporal resolution, the precision of the measurements, and the usefulness of the data. The presented analysis is focused on DInSAR results exploitation of various ground subsidence phenomena (groundwater withdrawal, soil compaction, mining subsidence, evaporite dissolution subsidence, and volcanic deformation) with different displacement patterns in a selection of subsidence areas in Spain. Finally, a cost comparative study is performed for the different techniques applied.The different research areas included in this paper has been supported by the projects: CGL2005-05500-C02, CGL2008-06426-C01-01/BTE, AYA2 010-17448, IPT-2011-1234-310000, TEC-2008-06764, ACOMP/2010/082, AGL2009-08931/AGR, 2012GA-LC-036, 2003-03-4.3-I-014, CGL2006-05415, BEST-2011/225, CGL2010-16775, TEC2011-28201, 2012GA-LC-021 and the Banting Postdoctoral Fellowship to PJG

Contribución de la interferometría SAR diferencial (InSAR) al estudio de la subsidencia del terreno de la Vega Media del Segura (Murcia): experiencias y tendencias futuras

XVII Congreso de la Asociación Española de Teledetección. Murcia 3-7 octubre 2017La Vega Media del Segura (VMS) se localiza en el sector este de la Cordillera Bética. El valle está relleno por sedimentos recientes (Holoceno-Plioceno) potencialmente deformables que han sido depositados por la acción de los ríos Segura y Guadalentín. La extracción de agua subterránea de los niveles permeables que constituyen el acuífero conlleva la consolidación de los materiales deformables, dando lugar a asientos de la superficie del terreno. La Interferometría SAR diferencial (InSAR) es una técnica remota que permite monitorizar de forma efectiva y precisa amplias extensiones del territorio. En este trabajo se describe las diferentes experiencias llevadas a cabo por los autores en la VMS, que han permitido avanzar en el entendimiento del funcionamiento hidrogeológico del acuífero para la comprensión del comportamiento geomecánico del subsuelo, así como para monitorizar los desplazamientos del terreno desde el año 1994 usando imágenes ERS, ENVISAT y TerraSAR-X, contribuyendo de forma efectiva al estudio, caracterización y modelización del fenómeno. Por último, se describen las tareas futuras a desarrollar haciendo uso de nuevos sensores SAR con el fin de asegurar la continuidad de la información disponible para el estudio de este fenómeno a lo largo del tiempo.Departamento de Ingeniería Civil, Universidad de Alicante, EspañaGeohazards InSAR Laboratory and Modeling Group, Instituto Geológico y Minero de España, EspañaDepartamento de Física, Ingeniería de Sistemas y Teoría de la Señal, Universidad de Alicante, EspañaDepartamento de Teoria Senyal i Comunicacions, Universitat Politècnica de Catalunya, EspañaDepartment of Earth Sciences, Environment and Resources, University of Naples, EspañaDares Technology, Barcelona, Españ

Research Group on Earth Observation, Geological Risks and Climate Change (OBTIER)

[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.Peer reviewe