Mt. Etna Ground Deformation Detected by SISTEM Approach Using GPS Data and Multiple SAR Sensors
Puglisi, Giuseppe1; Guglielmino, Francesco1; Cocorulllo, Chiara1; Sansosti, Eugenio2; Pepe, Susi2; Solaro, Giuseppe3; Casu, Francesco3; Ruch, Joel4; Zoffoli, Simona5
1Istituto Nazionale di Geofisica e Vulcanologia, ITALY; 2IREA, National Research Council (CNR), Napoli, ITALY; 3IREA, National Research Council (CNR), Napoli, Italy, ITALY; 4University of RomaTre, Rome, ITALY; 5Italian Space Agency (ASI), Rome, ITALY
Thanks to the availability of multiple SAR datasets acquired on Mt. Etna during the 2009-2010 time span, we adopted the SISTEM integration method in order to image the ground deformation affecting the volcano by considering information obtained from both SAR and GPS data. In particular we use both ascending and descending views of C-band ENVISAT and X-band Cosmo-SkyMed sensors, and the ascending view of L-band ALOS sensors. ALOS and COSMO-SkyMed SAR data have been acquired in the framework of SAR4Volcanoes research project, within a cooperation agreement between the Japan Aerospace Exploration Agency (JAXA) and ASI. The ENVISAT data have been acquired in the framework ESA CAT.1 5843 project. The SAR data have been analyzed by using a time series approach, based on the SBAS technique. Thanks to the availability of dense (105 benchmarks) geodetic in situ data collected during GPS surveys on Mt. Etna, it was possible to validate and integrate the SAR data with the GPS ground deformation data applying the SISTEM approach. The SISTEM approach simultaneously integrates all the available datasets (i.e. GPS displacement vectors on sparse benchmarks and SAR displacement maps), providing the high-resolution 3D displacement map by taking advantage of the positive features of each datasets, i.e. the availability of multiple view geometries of COSMO-SkyMed and ENVISAT data, together with the high temporal and spatial resolution of the COSMO-SkyMed data, the good coherence of ALOS L-band interferometric data, and the 3D displacements component provided by GPS with sub-cm accuracy level. We apply the SISTEM method to compute 3D high-resolution surface displacement maps of Mt. Etna related to ground deformations referring to 2009-2010 time-span. The SISTEM results are consistent with the geophysical and volcanological background knowledge of the dynamic of Mt. Etna during the 2009-2010 period, showing a general inflation of the entire volcanic edifice coupled with the ESE sliding of the eastern and southeastern flank. The displacement pattern resulting by applying the SISTEM integration method provides an accurate spatial characterization of ground deformation, well constrained by the multiple SAR data and ground GPS measurements.