Monitoring critical infrastructure and anthropogenic hazards in Malaga province (southern Spain) using SAR remote sensing

Land surface is in constant motion due to both natural causes and human activity. Over time, many measurement techniques have been developed to study the deformation of the earth's surface. Some of them, despite having different levels of accuracy, are slow and time consuming (e.g., classical geodetic techniques). The introduction of space geodesy techniques such as GNSS systems and SAR remote sensing have offered new opportunities for precision deformation control in the field of space geodesy. In particular, using satellite radar interferometry (InSAR) as an Earth Observation routine technique, the deformation of large areas of the terrain can be monitored providing displacements at a relatively low cost compared with other ground-based techniques. Nowadays, we are living in the golden age of InSAR as there has never been as much SAR data from different missions as there is today. Of particular importance is the Copernicus program of the European Commission and ESA, which provides us with an inexhaustible source of free SAR data with extraordinary potential for monitoring the earth's surface thanks to the constellation of Sentinel-1 SAR satellites. Thanks to the great capability of SAR remote sensing, many civil infrastructures can be monitored and inspected from space without the need for physical intervention on the ground, greatly reducing costs and execution time. The advanced InSAR time series algorithms allow us to investigate the displacements of these infrastructures with uncertainties of the order of 1 mm/year, interpreting time series of interferometric phases at coherent point reflectors (PS). The use of C-band SAR data from ERS-1/2, Envisat, and Sentinel-1 has allowed us to monitor the southeast of the province of Málaga in southern Spain during the last thirty years, obtaining a deformation pattern of some critical infrastructures in the area. We can highlight, among them: the Limonero dam inaugurated in 1983, whose reservoir regulates the avenues of the Guadalmedina river and serves as a water supplying source for the city of Malaga; the Málaga-Costa del Sol international airport, an important airport for Spanish tourism as it is the main airport serving the Costa del Sol; the Málaga harbor, an industrial area, or some roads and railways. Of special importance is an urban sector with an intensive overexploitation of aquifers. Due to the increase in population because of the expansion of the tourism industry in the Benalmádena coast and Torremolinos area, the aquifers are being affected after the intensive overexploitation of groundwater with the consequent subsidence of the terrain, continuous and increased over time. In this contribution, we show our results of the SAR remote sensing application in this area of the southern Spanish coast.