A first approach for displacement analysis in Lisbon Downtown using PS-InSAR

Lisbon Downtown presents unique geomorphologic properties which makes it an area prone to terrain instability. Serious accidents have occurred there, namely, during the 1755 earthquake and a flooding event at the extension of a subway line, demanding a frequent monitorization for safety reasons and expense minimization. In this study, Permanent Scatterers technique is applied. The calculated displacement velocities are compared to those obtained from levelling operations. Possible causes for the discrepancy are presented in the paper. Besides a subsidence trend, a seasonal behaviour is also detected, probably related to aquifer recharge or tides. (C) 2014 The Authors. Published by Elsevier Ltd.