Co-seismic deformation due to the Tohoku-Oki Earthquake measured by Envisat-ASAR data and GPS

On March 11th, 2011, 05:46 UTC, a giant earthquake of magnitude Mw=9.0 occurred off the Pacific coast of Tohoku, Honshu Island, Japan. Massive damage has been reported, mainly related to the subsequent tsunami. In this work we present first results concerning the displacement induced by the Tohoku-oki earthquake by using ASAR ENVISAT data acquired few days before and after the event. The work points out the reliability of ASAR ENVISAT data to provide interferometric-based displacement field even though the satellite is recently came into a new operative phase with degraded orbital control and SAR data were processed in an emergency framework soon after the acquisition without precise orbital records. After removing artefacts due to strong orbital errors, the interferometric deformation pattern is mainly related to the coseismic displacement and it results comparable to that provided by the GEONET GPS network which has an unique density of in situ measurements found elsewhere in the world.