DInSAR deformation time series for monitoring urban areas: The impact of the second generation SAR systems

We investigate the capability improvement of the DInSAR techniques to map deformation phenomena affecting urban areas, by performing a comparative analysis of the deformation time series retrieved by applying the full resolution Small BAseline Subset (SBAS) DInSAR technique to selected sequences of SAR data acquired by the ENVISAT, RADARSAT-1 and COSMO-SkyMed (CSK) SAR data. The presented study, focused on the city of Napoli (Italy), allows us to quantify the dramatic increase of the DInSAR coherent pixel density achieved by exploiting the high resolution X-Band CSK SAR images with respect to the RADARSAT-1 and ENVISAT products, respectively; this permits us to analyze nearly all the structures located within the investigated urbanized area and, in many cases, also portions of a same building. © 2012 IEEE

An integrated approach for monitoring soil settlements at the VIrgo site

The Virgo detector, currently in its 2nd generation configuration Advanced Virgo (AdV), is a Michelson interferometer aimed at the gravitational waves research and at opening a new window on the study of the Universe. It is made of two orthogonal arms being each 3 kilometers long and is located at the site of the European Gravitational Observatory (EGO), in the countryside near Pisa, Italy. After the construction of the Virgo facilities completed in 2002, over the years a steady subsidence process has been observed as a consequence of the building and embankment overloads. In consideration of the subsoil characteristics, whose surface portion is mainly formed by a 25÷60 m thickness layer of clay with limited thin layers of sands, the evolution of settlements was expected and properly considered for the design of the civil engineering infrastructures, so that the vacuum tubes can be readjusted to keep the original alignment. However, along 15 years of time life, the initial estimates of the expected displacements were continuously compared with the observed effects. The measured settlements have been regularly monitored and adopted for implementing the necessary realignment activities. This paper reports the monitoring activities conducted over the years, mainly consisting of regular high accuracy levelling surveys, periodically integrated by GPS and classical theodolite measurements. These sets of measurement were adopted to perform the Virgo realignment procedure needed to keep the interferometer rigidly tied in a 3x3km plane. In order to improve the knowledge on the trend of the settlements affecting the Virgo infrastructures, an analysis based on differential interferometry using satellite Synthetic Aperture Radar (SAR) data has been performed and compared with the outcome from in-situ data

The evolution of the Sciara del Fuoco subaerial slope during the 2007 Stromboli eruption: Relation between deformation processes and effusive activity

Focusing on the Island of Stromboli, this research investigates whether airborne remote sensing systems, such as those based on digital photogrammetry and laser scanner sensors, can be adopted to monitor slope deformation and lava emplacement processes in active volcanic areas. Thanks to the capability of extracting accurate topographic data and working on flexible time schedules, these methods can be used to constrain the regular and more frequent measurements derived from satellite observations. This work is dedicated to the monitoring of Stromboli's volcanic edifice which is beneficial when obtaining quantitative data on the geometry of deformation features and the displaced (failures and landslides) and emplaced (lava flows) volumes. In particular, we focus on the capability of extracting average effusion rates from volume measurements that can be used to validate or integrate satellite-derived estimates. Since 2001, a number of airborne remote sensing surveys, namely Digital Photogrammetry (DP) and Airborne Laser Scanning (ALS), have been carried out on Stromboli's volcano to obtain high resolution Digital Elevation Models (DEM) and orthophotos with sub-meter spatial resolution and a time schedule suitable for monitoring the morphological evolution of the surface during the quiescent phases. During the last two effusive eruptions (2002–2003 and 2007) the surface modifications, created on the Sciara del Fuoco slope and on the crater area as a consequence of effusive activity, were quantified and monitored using the same methodologies. Thiswork, which is based on the results obtained from the multi-temporal quantitative analysis of the data collected from 2001 to 2007, mainly focuses on the 2007 eruption but also accounts for analogies and differences regarding the 2002–2003 event. The 2007 eruption on the Sciara del Fuoco slope from 27 February until 2 April, produced a compound lava field including a lava delta on the shoreline, discharging most of the lava into the sea. The comparison of the 2007 DEMs with a pre-eruption surface (2006 LIDAR survey) allowed for the evaluation of the total lava volume that accumulated on the subaerial slope while two syn-eruption DEMs were used to calculate the average effusion rates during the eruption. Since the evolution of a lava field produced during an eruption can be seen as a proxy for the magma intrusion mechanism, hypotheses are formulated on the connection between the lava discharge and the instabilities suffered by the slope

Analisi delle potenzialità dei dati satellitari ad alta risoluzione per la generazione di ortofoto

Perugi

GPS/GIS Integration: Theoretical and Application Problems

Ed. E.S.A