Detection of terrain changes in southern Denmark using persistent scatterer interferometry

Since 1991, a number of European satellites have acquired data of the Earth’s surface for environmental monitoring. In general, a satellite will orbit the Earth in about 1½ hours and it takes 35 days before an ERS or ENVISAT satellite repeats radar scanning of the same position. For younger generations of satellites, such as RADARSAT and TERRA, the scanning repeat interval has decreased to 24 and 11 days, respectively, so that hundreds of radar scenes of the same place, produced over the past c. 20 years, are now available

DInSAR analysis of aquifer compaction due to ground water extraction in the Segura River Basin

The aim of this work is to analyze the subsidence affecting the whole Segura River Basin (1900 km2) using Differential Interferometry (DInSAR). This technique is capable of estimating mean deformation velocity maps of ground surface and displacement time series from Synthetic Aperture Radar (SAR) images. The processing of some datasets acquired between 1992 and 2008 from ERS and ENVISAT sensors have allowed to detect the highest rates of groundwaterrelated subsidence recorded in Europe (>10 cm/yr). These data have been validated against ground subsidence measurements and correlated with subsidence triggering and conditioning factors by means of a Geographical Information System (GIS). Retrieved results have permitted to improve the knowledge of the mechanisms that control aquifer compaction due to ground water extraction and the associated effects in the buildings and infrastructures of exposed urban areas.Peer reviewe

Advanced interpretation of subsidence in Murcia (SE Spain) using A-DInSAR data – modelling and validation

Subsidence is a natural hazard that affects wide areas in the world causing important economic costs annually. This phenomenon has occurred in the metropolitan area of Murcia City (SE Spain) as a result of groundwater overexploitation. In this work aquifer system subsidence is investigated using an advanced differential SAR interferometry remote sensing technique (A-DInSAR) called Stable Point Network (SPN). The SPN derived displacement results, mainly the velocity displacement maps and the time series of the displacement, reveal that in the period 2004–2008 the rate of subsidence in Murcia metropolitan area doubled with respect to the previous period from 1995 to 2005. The acceleration of the deformation phenomenon is explained by the drought period started in 2006. The comparison of the temporal evolution of the displacements measured with the extensometers and the SPN technique shows an average absolute error of 3.9±3.8 mm. Finally, results from a finite element model developed to simulate the recorded time history subsidence from known water table height changes compares well with the SPN displacement time series estimations. This result demonstrates the potential of A-DInSAR techniques to validate subsidence prediction models as an alternative to using instrumental ground based techniques for validation.The European Space Agency (ESA) Terrafirma project has funded all the SAR data processing with the SPN technique as well as the subsidence interpretation and modelling work presented above. Additionally, this work has been partially financed by the Spanish Geological and Mining Institute (IGME) with the collaboration of the Regional Government of Murcia and the universities of Alicante (UA) and Rey Juan Carlos (URJC). This work has been also supported by the Spanish Ministry of Science and Research (MICINN) and EU FEDER under project TEC2008-06764-C02-02

Sistemas radar aplicados a la investigación de subsidencia y movimientos de ladera

En este trabajo se presentan los sistemas radar satélite y terrestres, así como los métodos de análisis de imágenes radar clásicos y avanzados para la investigación de los movimientos del terreno, haciendo énfasis en la subsidencia y los movimientos de ladera. Para ello en primer lugar se describen los distintos sensores radar disponibles así como las principales características de las imágenes radar generadas. A continuación se detallan los aspectos fundamentales de la interferometría diferencial, de los distintos métodos de interferometría diferencial avanzada y del radar terrestre. Finalmente se presentan los resultados obtenidos en distintas zonas de estudio: la subsidencia por explotación del acuífero en el área metropolitana de Murcia, la subsidencia minera y los movimientos de ladera de la Sierra de Cartagena, los movimientos de ladera de la cuenca del río Gállego y el deslizamiento del Portale

Radar systems applied to subsidence and landslides investigations

En este trabajo se presentan los sistemas radar satélite y terrestres, así como los métodos de análisis de imágenes radar clásicos y avanzados para la investigación de los movimientos del terreno, haciendo énfasis en la subsidencia y los movimientos de ladera. Para ello en primer lugar se describen los distintos sensores radar disponibles así como las principales características de las imágenes radar generadas. A continuación se detallan los aspectos fundamentales de la interferometría diferencial, de los distintos métodos de interferometría diferencial avanzada y del radar terrestre. Finalmente se presentan los resultados obtenidos en distintas zonas de estudio: la subsidencia por explotación del acuífero en el área metropolitana de Murcia, la subsidencia minera y los movimientos de ladera de la Sierra de Cartagena, los movimientos de ladera de la cuenca del río Gállego y el deslizamiento del Portalet.In this paper satellite and ground based radar systems are presented, as well as standard and advanced differential interferometry techniques, for subsidence and landslides research. In the fist part available radar sensors are described as well as the main characteristics of radar images (SAR images). Then the key aspects of standard differential interferometry, advanced differential interferometry and ground based radar are shown. Finally, results retrieved in different study areas are presented: subsidence due to ground water withdrawal in the metropolitan area of Murcia, mining subsidence and mass movements in Sierra de Cartagena, landslides in river Gállego basin and landslides in Portalet.Los resultados que se muestran en este trabajo han sido financiados por el Instituto Geológico y Minero de España, y los proyectos GMES Terrafirma de la Agencia Espacial Europea, el proyecto Galahad del Sexto Programa Marco, así como por los convenios de investigación existentes con la Región de Murcia