Analysis of the Lisbon metropolitan area using the P-SBAS service of the Geohazards Exploitation Platform

Abstract

[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.