Relatively to the Valle d’Aosta region test site, a space-borne analysis, using the DInSAR technique, was done using the ESA’s Grid Processing On-Demand (G-POD) service. The ASAR-Envisat dataset, available through the Virtual Archive 4 of ESA (by the Category-1A project, part of the ESA Geohazard Supersites initiative), was processed by using the G-POD service. The SAR dataset, made of 38 images acquired from ascending orbit (track 301) between June 2004 and November 2010, has been analyzed with the SBAS-DInSAR technique. The ASAR-Envisat satellite acquires images characterized by: - Band acquisition: C Band - Wavelength (cm): 5.6 - Incident angle (°): 23° - Azimuth/ground range resolution (m): ≈ 4/20 - Revisit time (days): 35 - Life status: 2002 – 2010 - Space agency: ESA Regarding the G-POD threshold setting of the SBAS processing, the following parameters were used: - Max Perpendicular Baseline (m): 400 - Max Temporal Baseline (days): 1500 - Ground Pixel Dimension (m): 40 - Coherence Threshold: 0.8 - Area of Interest (AOI): entire frame - REF point: Lat. 45.737049 – Lon. 7.31899 The achieved SBAS measurements are provided in geocoded coordinates (Lat./Lon. and UTM WGS84), and are reported in an ASCII file. The SBAS results, relevant to the entire frame (normally around 100x100 km), have an accuracy of 1 mm/yr concerning the mean velocity measurements, and 5 mm for the deformation measurements [Casu et al., 2006]

Relatively to the Grange Orgiera test site, a space-born analysis using the DInSAR technique, was done using the ESA’s Grid Processing On-Demand (G-POD) service, for a specific area of interest (AOI). The ASAR-Envisat dataset, available through the Virtual Archive 4 of ESA (by the Category-1A project, part of the ESA Geohazard Supersites initiative), was processes by using the G-POD service. The SAR dataset, made of 21 images acquired in ascending orbit (track 301) between April 2005 and October 2010, has been analyzed with the SBAS-DInSAR technique. The ASAR-Envisat satellite acquires images characterized by: - Band acquisition: C Band - Wavelength (cm): 5.6 - Incident angle (°): 23° - Azimuth/ground range resolution (m): ≈ 4/20 - Revisit time (days): 35 - Life status: 2002 – 2010 - Space agency: ESA Regarding the G-POD threshold setting of the SBAS processing, the following parameters were used: - Max Perpendicular Baseline (m): 400 - Max Temporal Baseline (days): 1500 - Ground Pixel Dimension (m): 80 - Coherence Threshold: 0.7 - Area of Interest (AOI): selected AOI close to the test site - REF point: Lat. 44.5838 – Lon. 7.1434 The achieved SBAS measurements are provided in geocoded coordinates (Lat/Lon and UTM WGS84), and are reported in an ASCII file. The SBAS results, relevant to the entire frame (normally around 100x100 km) have an accuracy of 1 mm/yr concerning the mean velocity measurements, and 5 mm for the deformation measurements [Casu et al., 2006].

The SAR ground deformation time series relevant to Grange Orgiera test site include deformation data obtained from ASAR-Envisat satellite acquisitions (images available in the framework of Category-1A project, part of the ESA Geohazard Supersites initiative), and elaborated by the ESA’s G-POD service with the SBAS technique. In particular provided 41555 measure points, for the observed period from April 2005 to October 2010, relative to the area of interest. The archive provide for each SBAS targets: - East and North UTM WGS84 coordinates (m); - Temporal interferometric coherence [CohT]; - Deformation velocity (cm/year) [Vel]; - Azimuth and Range coordinates [Az/Rg]; - Latitude and Longitude coordinates (deg) [Lat/Lon]; - Topography (m) [RT]; - Deformation Data (cm), related to the date of the exploited SAR images. The date of the exploited images are expressed as: [year+((month-1)*30+day)/365]. The SAR results, relevant to the entire frame (normally around 100x100 km), have an accuracy of 1 mm/yr concerning the mean velocity measurements, and 5 mm for the deformation measurements [Casu et al., 2006]. The deformation time series present a monthly temporal sampling, and provide long time series of deformation, allowing to follow the evolution of surface displacements over time.

The SAR ground deformation time series relevant to Valle d’Aosta region include deformation data obtained from ASAR-Envisat satellite acquisitions (images available in the framework of Category-1A project, part of the ESA Geohazard Supersites initiative), and elaborated by the ESA’s G-POD service with the SBAS technique. In particular, the analysis provided 23634 measure points, for the observed period from April 2004 to November 2010. The analysis provided for each SBAS targets: - East and North UTM WGS84 coordinates (m); - Temporal interferometric coherence [CohT]; - Deformation velocity (cm/year) [Vel.]; - Azimuth and Range coordinates [Az./Rg.]; - Latitude and Longitude coordinates (deg.) [Lat./Lon]; - Topography (m) [RT]; - Deformation Data (cm), related to the acquisition dates of the exploited SAR images. The dataset of the exploited images are expressed as: [year+((month-1)*30+day)/365]. The SBAS results, relevant to the entire frame (normally around 100x100 km), have an accuracy of 1 mm/yr concerning the mean velocity measurements, and 5 mm for the deformation measurements [Casu et al., 2006] The deformation time series present a monthly temporal sampling, and provide long time series of deformation, allowing to follow the evolution of surface displacements over time.

One of the aims of the Hammer project is to provide SAR deformation measurements. For this purpose, the Grid Processing On-Demand (G-POD) service was used to provide SAR deformation maps and associated time series for the test sites of Hammer. The G-POD SBAS-DInSAR service was developed through a collaboration between CNR-IREA and ESA-RSS, and is available from November 2014. The service is provided through a user-friendly web-interface, which allows users to perform the full SBAS-DInSAR chain, from RAW data focusing to displacement time series generation. G-POD can process the ESA’s ERS-1/2 and Envisat ASAR data retrieved throughout the Virtual Archive 4 (http://eo-virtual-archive4.esa.int/ in the framework of Supersite Initiative), and can generate single interferogram and/or a multi-temporal analyses. The G-POD service requires dataset selection over a specific area of interest (AOI) together with parameters and threshold setting (e.g. perpendicular baseline, temporal baseline, coherence threshold).