On the use of satellite Remote Sensing for detecting surface effects due to subsurface processes

Abstract

Nowadays, satellite Remote Sensing accounts for a wide range of instruments and sensors with an unprecedented capability to study the physical processes causing earthquakes, volcanic eruptions, slope instabilities, and the effects of human activities, like mining, aquifer exploitation, fluids extraction. Remote Sensing allows the systematic observation of the Earth surface covering large areas (up to hundreds km2), over long time period (up to annual scales). In particular, the novel generation of Synthetic Aperture Radar (SAR) and Optical missions have significantly improved the capability to detect changes in the scene and, thanks to innovative processing algorithms, to measure displacements with increased accuracies (up to mm scales). This is the case of Interferometric SAR (InSAR) and Advanced-InSAR techniques that demonstrated their effectiveness to investigate crustal faulting stemming from the detection of surface deformation patterns. Moreover, during a seismic sequence, satellite data are used to map damages in built areas and coseismic deformation due to the main earthquakes. In volcanic studies InSAR allows measuring pre-eruptive inflation, co-eruptive deflation and the post-eruptive response. The spatial-temporal evolution of volcanic processes, the “breathing” of a volcano, can be monitored with temporal series of InSAR interferograms using multitemporal InSAR techniques. The measured deformation can be used as a constraint for the formulation of the inverse problem, i.e., to retrieve information concerning the depth, size, shape of the magmatic source. Finally, natural and anthropogenic subsidence can be monitored over long temporal span in order to follow their evolution and possible impact on the environment.