Milano, Italy
Milano, Italy

Time filter

Source Type

Bonforte A.,Italian National Institute of Geophysics and Volcanology | Guglielmino F.,Italian National Institute of Geophysics and Volcanology | Coltelli M.,Italian National Institute of Geophysics and Volcanology | Ferretti A.,Tele Rilevamento Europa | Puglisi G.,Italian National Institute of Geophysics and Volcanology
Geochemistry, Geophysics, Geosystems | Year: 2011

A study of the deformation pattern of Mount Etna volcano based on the results from the Permanent Scatterers (PS) technique is reported. Ground motion data provided by the interferometric synthetic aperture radar (InSAR) PS technique from 1995 to 2000 are compared and validated by GPS data. An analysis of the ascending and descending line of sight (LOS) components of ground velocities has yielded detailed ground deformation maps and cross sections. This analysis allows detection and constraint of discontinuities in the surface velocity field. LOS velocities have then been combined to calculate the vertical and horizontal (E-W) ground velocities. A wide inflation of the edifice has been detected on the western and northern flanks (over an area of about 350 km2). A seaward motion of the eastern and southern flanks has also been measured. PS data allows the geometry and kinematics of the several blocks composing the unstable flanks to be defined even in the highly urbanized areas, and their displacement rates have been measured with millimeter precision. This analysis reveals the extension of some features beyond their field evidences and defines new important features. The results of this work depict a new comprehensive kinematic model of the volcano highlighting the gravitational reorganization of the unbuttressed volcanic pile on its slippery clay basement on the southern flank, but an additional drag force due to a strong subsidence of the continental margin facing the Etna volcano is necessary to explain the PS velocity field observed on the eastern flank. Copyright © 2011 by the American Geophysical Union.

Rocca F.,Polytechnic of Milan | Prati C.,Polytechnic of Milan | Ferrettib A.,Tele Rilevamento Europa
Annals of GIS | Year: 2010

Space-borne synthetic aperture radar interferometry (INSAR) is a well-known widely used remote sensing technique to get precise (to the millimeter) surface deformation measurements on large areas (thousands of square kilometers) and high spatial density of measurement points (hundreds per square kilometer). A short review of the INSAR basics is dedicated to the readers who are not INSAR specialists. Then, an analysis of the improvement of ground motion measurement offered by multiple repeated space-borne SAR observations gathered by the new generation of satellites is given and compared with ground-based radar results. Examples from Cosmo-SkyMed and TERRASAR-X are shown and compared with C-band or L-band systems. Finally, the impact of the forthcoming C-band satellites like Sentinel 1 A, B is discussed. © 2010 Taylor & Francis.

Rucci A.,Tele Rilevamento Europa | Vasco D.W.,University of California at Berkeley | Novali F.,Tele Rilevamento Europa
Geophysical Journal International | Year: 2013

Combining interferometric synthetic aperture radar (InSAR) data from ascending and descending orbits we estimate both quasi-vertical and quasi-east-west displacements for a region in central Algeria, an area encompassing an active large-scale carbon dioxide storage project, the In Salah gas storage project. The surface deformation associated with the injection into three horizontal wells is clearly visible in the InSAR estimates. We find that the addition of the quasi-horizontal displacement data enables us to discriminate between source models producing similar vertical displacements. In particular, predictions from a model consisting of a distribution of volume changes restricted to the reservoir depth interval satisfies the quasivertical data but does not match the quasi-east-west displacement data. However, aperture changes on subvertical damage zones, intersecting each of the injection wells, give rise to displacements matching both the quasi-east-west and vertical components. In all cases, we can match the observations with the most significant volume and aperture changes in regions immediately surrounding the injection wells. © Published by Oxford University Press on behalf of The Royal Astronomical Society 2013.

Vasco D.W.,Lawrence Berkeley National Laboratory | Rucci A.,Polytechnic of Milan | Ferretti A.,Tele Rilevamento Europa | Novali F.,Tele Rilevamento Europa | And 4 more authors.
Geophysical Research Letters | Year: 2010

Interferometric Synthetic Aperture Radar (InSAR) data, gathered over the In Salah CO2 storage project in Algeria, provide an early indication that satellite-based geodetic methods can be effective in monitoring the geological storage of carbon dioxide. An injected mass of 3 million tons of carbon dioxide from one of the first large-scale carbon sequestration efforts, produces a measurable surface displacement of approximately 5 mm/year. Using geophysical inverse techniques, we are able to infer flow within the reservoir layer and within a seismically detected fracture/fault zone intersecting the reservoir. We find that, if we use the best available elastic Earth model, the fluid flow need only occur in the vicinity of the reservoir layer. However, flow associated with the injection of the carbon dioxide does appear to extend several kilometers laterally within the reservoir, following the fracture/fault zone. Copyright © 2010 by the American Geophysical Union.

Bock Y.,University of California at San Diego | Wdowinski S.,University of Miami | Ferretti A.,Tele Rilevamento Europa | Novali F.,Tele Rilevamento Europa | Fumagalli A.,Tele Rilevamento Europa
Geochemistry, Geophysics, Geosystems | Year: 2012

Coastal regions are increasingly affected by larger storms and rising sea level predicted by global warming models, aggravating the situation in the city of Venice where tidal-induced seasonal flooding coupled with natural and anthropogenic subsidence have been perennial problems. In light of accelerated efforts to protect Venice from the rise in sea level we assess land subsidence in the Venice Lagoon over the last decade. Through a combined analysis of GPS position time series from 2001.55 to 2011.00 for four stations installed by the Magistrato alle Acque di Venezia and thousands of observations of InSAR permanent scatterers using RADARSAT-1 images from 2003.3 to 2007.85, we determine that the northern lagoon subsides at a rate of 2-3 mm/yr, whereas the southern lagoon subsides at 3-4 mm/yr. The city of Venice continues to subside, at a rate of 1-2 mm/yr, in contrast to geodetic studies in the last decade of the 20th Century suggesting that subsidence has been stabilized. The GPS results indicate a general eastward tilt in subsidence and that the natural subsidence rate related to the retreat of the Adriatic plate subducting beneath the Apennines is at least 0.4-0.6 mm/yr. Our combined GPS and InSAR analysis demonstrates high spatial resolution in the vertical direction with a precision of 0.1-0.2 mm/yr with respect to a global reference frame. Continued efforts to secure the city of Venice from flooding must also take into account the significant local and regional subsidence rates as well as the expected rise in sea level. Copyright 2012 by the American Geophysical Union.

Belson A.,Tele Rilevamento Europa | Gervasi C.,Tele Rilevamento Europa
Hart's E and P | Year: 2010

Interferometric Synthetic Aperture Radar (InSAR), a remote sensing technique based on satellite radar systems circling the globe, is playing a key role in allowing reservoir modeling from space. The technique is capable of accurately measuring ground displacement and operators that are using the technology, include BP, ConocoPhillips, Devon, Eni, PDO, and Shell. Satellite radar sensors broadcast signals toward Earth and illuminated targets reflect back-scattered signals to the satellite where they are read and stored. A sequence of temporally spaced images can be acquired over the same area, as the radar satellites regularly retrace over the same orbit. SqueeSAR also enables the user to process this energy and detect ground displacement in DS areas where there are poor PS levels. InSAR is more advanced, handling multi-image datasets, identifying PS and DS groundpoints, and providing millimeter accuracy on ground displacement values.

Comola F.,Ecole Polytechnique Federale de Lausanne | Janna C.,University of Padua | Lovison A.,University of Padua | Minini M.,Tele Rilevamento Europa | And 2 more authors.
Geophysics | Year: 2015

When large volumes of fluids are removed from or injected into underground formations for, e.g., hydrocarbon and water production, CO2 storage, gas storage, and geothermal energy exploitation, monitoring of surface deformations coupled to numerical modeling improves our understanding of reservoir behavior. The ability to accurately simulate surface displacements, however, is often impaired by limited information on reservoir geometry, waterdrive strength, and fluid-geomechanical parameters characterizing the geologic formations of interest. We have investigated the ability of efficient global optimization (EGO) to reduce the parameter uncertainties usually affecting geomechanical modeling. EGO is used to identify the parameter set that minimizes the difference in land displacements obtained from synthetic aperture radar (SAR)-derived measurements and 3D geomechanical modeling. We have tested the approach on the Tengiz giant oil field, Kazakhstan, where large uncertainties affect our knowledge of geomechanical parameters and pore pressure evolution. SqueeSAR on ENVISAT and RADARSAT-1 images acquired between 2004 and 2007 provided a set of high-precision, high-areal-density subsidence measurements of the test site. Based on the available information, a 3D geomechanical model of the reservoir has been developed using the elastoplastic finite-element code GEPS3D. Our results indicated that EGO efficiently identifies the global optimum in the parameter space, yielding a significant reduction in the difference between modeled and measured land subsidence. The match between simulated and SAR-measured horizontal displacements was developed as validation of the EGO calibration, which thus proved an effective and rather inexpensive method for the simultaneous management of several uncertainties and the reliable quantification of the rock properties. © 2016 Society of Exploration Geophysicists.

Peltier A.,CNRS Paris Institute of Global Physics | Bianchi M.,Tele Rilevamento Europa | Kaminski E.,CNRS Paris Institute of Global Physics | Komorowski J.-C.,CNRS Paris Institute of Global Physics | And 2 more authors.
Geophysical Research Letters | Year: 2010

The Permanent Scatterers Synthetic Aperture Radar Interferometry (PSInSAR) is a technique, which aims at ground deformation mapping with millimetric precision. In the framework of the Globvolcano ESA project, we evaluated a PSInSAR derived approach to monitor ground deformation in highly active volcanic areas, based on the example of Piton de La Fournaise. The Permanent Scatterer (PS) velocities show two main areas of deformation: (1) the eastern flank displaying old lava flow subsidence (0.05-0.13 m.y-1); and (2) the summit cone highly disturbed by eruptions. The PS time series for the summit area agree with the cGPS trends with small long-term (weeks/months) ground displacements preceding eruptions (0.05-0.35 m.y-1) and large rapid ground displacements linked to eruptions. Despite some limitations, such as the loss of coherence during the most rapid ground displacements and lava flow emplacement, PSInSAR and its derived approach provide a reliable inference of the volcano ground deformation over large areas. Copyright 2010 by the American Geophysical Union.

Loading Tele Rilevamento Europa collaborators
Loading Tele Rilevamento Europa collaborators