Ground Deformations in the Corinth Rift, Greece, Investigated Through the Means of SAR Multitemporal Interferometry

International audienceThe Corinth Rift is one of the narrowest and fastest extending continental regions worldwide and has one of the highest seismicity rates in the Euro-Mediterranean region. At its western termination, several active faults are located beneath the city of Patras and the surrounding area, a region of major socioeconomic importance for Greece. Displacement rates for the period 2002-2010 obtained from ascending and descending ASAR/ENVISAT multitemporal interferometry are combined with Global Positioning System measurements from permanent and campaign stations to produce a map of vertical and east-west ground velocities. Cross sections are produced in order to quantify the deformation rates with higher precision. In the vertical, the motion combines tectonic deformation, urban subsidence, and subsidence due to deltaic sediments compaction. In the city of Patras and through the gulf of Patras, the northern continuation of the 2008 Movri earthquake fault is connected to the oblique transform zone of Rio. Further east, our observations suggest the existence of postseismic deformation at Aigion in the 15 years following the M w = 6.2, 15 June 1995 Aigion earthquake. The inferred deforming zone, assuming a simple slow slipping model, is located at the western end of the 1995 fault, with radius~3.5 km, centroid depth 4 km, and cumulated postseismic moment representing 28% of the coseismic. Alluvial fan deltas subside due to their compaction with a gradient that increases toward the shore. Several of those deltas are located in the hanging-wall of active faults