151 research outputs found
Generation of large scale digital evaluation models via synthetic aperture radar interferometry
We investigate the possibility to generate a large-scale Digital Elevation Model by applying the Synthetic Aperture Radar interferometry technique and using tandem data acquired by the ERS-1/ERS-2 sensors. The presented study
is mainly focused on the phase unwrapping step that represents the most critical point of the overall processing chain. In particular, we concentrate on the unwrapping problems related to the use of a large ERS tandem data set that, in order to be unwrapped, must be partitioned. The paper discusses the inclusion of external information (even rough) of the scene topography, the application of a region growing unwrapping technique and the insertion of possible constraints on the phase to be
retrieved in order to minimize the global unwrapping errors. Our goal is the generation of a digital elevation model relative to an area of 300 km by 100km located in
the southern part of Italy. Comparisons between the achieved result and a precise digital terrain model, relative to a smaller area, are also included
Modeling of ALOS and COSMO-SkyMed satellite data at Mt Etna: implications on relation between seismic activation of the Pernicana fault system and volcanic unrest
We investigate the displacement induced by the 2–3 April 2010 seismic swarm (the largest event being of Ml
4.3 magnitude) by means of DInSAR data acquired over the volcano by the Cosmo-SkyMed and ALOS radar
systems. Satellite observations, combined with leveling data, allowed us to perform a high-resolution modeling
inversion capable of fully capturing the deformation pattern and identifying the mechanism responsible
for the PFS seismic activation. The inversion results well explain high gradients in the radar line of sight displacements
observed along the fault rupture. The slip distribution model indicates that the fault was characterized
by a prevailing left-lateral and normal dip–slip motion with no fault dilation and, hence, excludes that
the April 2010 seismic swarm is a response to accommodate the stress change induced by magma intrusions,
but it is due to the tectonic loading possibly associated with sliding of the eastern flank of the volcano edifice.
These results provide a completely different scenario from that derived for the 22 September 2002 M3.7
earthquake along the PFS, where the co-seismic shear-rupture was accompanied by a tensile mechanism
associated with a first attempt of magma intrusion that preceded the lateral eruption occurred here a
month later. These two opposite cases provide hints into the behavior of the PFS between quiescence and unrest
periods at Etna and pose different implications for eruptive activity prediction and volcano hazard assessment.
The dense pattern of ground deformation provided by integration of data from short revisiting
time satellite missions, together with refined modeling for fault slip distribution, can be exploited at different
volcanic sites, where the activity is controlled by volcano-tectonic interaction processes, for a timely evaluation
of the impending hazards
FIFTEEN YEARS OF ERS AND ENVISAT DInSAR OBSERVATIONS AT MT. ETNA (ITALY) BY USING THE SBAS APPROACH
We exploited the Small BAseline Subset (SBAS)
technique and computed ground displacement maps
and time series by inverting 283 interferograms
generated from the ascending and 289 from the
descending orbits to reveal Mt. Etna surface
deformation from 1992 to 2006. Our analysis shows
that the volcano experienced magmatic
inflation/deflation and radial spreading of the west,
south and east flanks. In particular, the summit area
vertical deformation inverted its sign after 2000 and
clearly shows a deflation effect related to the 2001 and
2002 eruptive and seismic events. On the contrary, the
horizontal signals revealed on the eastern and western
flanks present significant and consistent motions
toward east and west, respectively, during the
investigated interval. Overall, the presented results
show the complex and articulated deformation
behavior of Mt. Etna and remark the possible
coexistence of both gravity and magma forcing
Volcanic Risk System (SRV): ASI Pilot Project to Support The Monitoring of Volcanic Risk In Italy by Means of EO Data
The ASI-SRV(Sistema Rischio Vulcanico) project
started at the beginning of the 2007 is funded by the Italian
Space Agency (ASI) in the frame of the National Space Plan
2003-2005 under the Earth Observations section for natural
risks management. Coordinated by the Istituto Nazionale di
Geofisica e Vulcanologia (INGV), which is responsible at national
level for the volcanic monitoring, the project has as main
objective to develop a pre-operative system based on EO data
and ground measurements integration to support the volcanic
risk monitoring of the Italian Civil Protection Department. The
project philosophy is to implement specific modules which allow
to process, store and visualize through Web GIS tools EO derived
parameters considering three activity phases: 1) knowledge and
prevention; 2) crisis; 3) post crisis. In order to combine
effectively the EO data and the ground networks measurements
the system will implement a multi-parametric analysis tool,
which represents and unique tool to analyze contemporaneously
a large data set of data in “near real time”. The SRV project will
be tested his operational capabilities on three Italian Volcanoes:
Etna,Vesuvio and Campi Flegrei.I.N.G.V. - O.V. SEZIONE DI NAPOLI
I.R.E.A. - C.N.R.
E.S.A.
A.S.I.PublishedNapoli1.10. TTC - Telerilevamentoope
Volcanic Risk System (SRV): ASI Pilot Project to Support The Monitoring of Volcanic Risk In Italy by Means of EO Data
The ASI-SRV(Sistema Rischio Vulcanico) project
started at the beginning of the 2007 is funded by the Italian
Space Agency (ASI) in the frame of the National Space Plan
2003-2005 under the Earth Observations section for natural
risks management. Coordinated by the Istituto Nazionale di
Geofisica e Vulcanologia (INGV), which is responsible at national
level for the volcanic monitoring, the project has as main
objective to develop a pre-operative system based on EO data
and ground measurements integration to support the volcanic
risk monitoring of the Italian Civil Protection Department. The
project philosophy is to implement specific modules which allow
to process, store and visualize through Web GIS tools EO derived
parameters considering three activity phases: 1) knowledge and
prevention; 2) crisis; 3) post crisis. In order to combine
effectively the EO data and the ground networks measurements
the system will implement a multi-parametric analysis tool,
which represents and unique tool to analyze contemporaneously
a large data set of data in “near real time”. The SRV project will
be tested his operational capabilities on three Italian Volcanoes:
Etna,Vesuvio and Campi Flegrei
Excess path delays from sentinel interferometry to improve weather forecasts
A synthetic aperture radar can offer not only an accurate monitoring of the earth surface deformation, but also information on the troposphere, such as the total path delay or the columnar water vapor at high horizontal resolution. This can be achieved by proper interferometric processing and postprocessing of the radar interferograms. The fine and unprecedented horizontal resolution of the tropospheric products can offer otherwise unattainable information to be assimilated into numerical weather prediction models, which are progressively increasing their resolving capabilities. A number of tricks on the most effective processing approaches, as well as a novel method to pass from multipass differential interferometry products to absolute tropospheric columnar quantities are discussed. The proposed products and methods are assessed using real Sentinel-1 data. The experiment aims at evaluating the accuracy of the derived information and its impact on the weather prediction skill for two meteorological events in Italy. The main perspective of the study is linked to the possibility of exploiting interferometric products from a geosynchronous platform, thus complementing the inherent high resolution of SAR sensors with the required frequent revisit needed for meteorological applications
Volcanic Risk System (SRV): ASI Pilot Project to Support The Monitoring of Volcanic Risk In Italy by Means of EO Data
The ASI-SRV(Sistema Rischio Vulcanico) project
started at the beginning of the 2007 is funded by the Italian
Space Agency (ASI) in the frame of the National Space Plan
2003-2005 under the Earth Observations section for natural
risks management. Coordinated by the Istituto Nazionale di
Geofisica e Vulcanologia (INGV), which is responsible at national
level for the volcanic monitoring, the project has as main
objective to develop a pre-operative system based on EO data
and ground measurements integration to support the volcanic
risk monitoring of the Italian Civil Protection Department. The
project philosophy is to implement specific modules which allow
to process, store and visualize through Web GIS tools EO derived
parameters considering three activity phases: 1) knowledge and
prevention; 2) crisis; 3) post crisis. In order to combine
effectively the EO data and the ground networks measurements
the system will implement a multi-parametric analysis tool,
which represents and unique tool to analyze contemporaneously
a large data set of data in “near real time”. The SRV project will
be tested his operational capabilities on three Italian Volcanoes:
Etna,Vesuvio and Campi Flegrei
The 2004–2006 uplift episode at Campi Flegrei caldera (Italy): Constraints from SBAS-DInSAR ENVISAT data and Bayesian source inference
We investigate the 2004–2006 uplift phase of Campi
Flegrei caldera (Italy) by exploiting the archive of ascending
and descending ENVISAT SAR data acquired from
November 2002 to November 2006. The SBAS-DInSAR
technique is applied to generate displacement mean velocity
maps and time series. An appropriate post-processing step is
subsequently applied to map the areas whose temporal
deformation behavior is correlated with that of the
maximum uplift zone. Our results show that the
deformation also extends outside the volcanological limits
of the Neapolitan Yellow Tuff caldera, without significant
discontinuities. The DInSAR data are inverted by
considering a finite spheroid and an isotropic pointsource.
The inversion results suggest that the new uplift is
characterized by a source location similar to the previous
small uplift event of 2000 and to the long term subsidence
of the 1990’s. In particular, the source is located at a depth
of about 3.2 km and very close to the city of Pozzuoli (about
800 m offshore, to the SW); the associated volume variation
is about 1.1 106 m3/year.PublishedL073081.10. TTC - TelerilevamentoJCR Journalreserve
SOLE Project – Demonstration of a Multistatic and Multiband Coherent Radar Network
The aim of the NATO-SPS SOLE project is demonstrating the feasibility and the high performance of a radar network thanks to photonics. Indeed, the coherence offered by photonics makes the proposed distributed radar system capable of an efficient implementation of MIMO processing and ISAR imaging, enhancing the performance in terms of resolution and precision. The advantage of a fully coherent, multistatic radar system here is experimentally proven by a 5-time cross-range resolution enhancement thanks to MIMO processing, and in an efficient focusing in ISAR imaging
Volcanic spreading of Vesuvius, a new paradigm for interpreting its volcanic activity
We integrate geologic, structural, leveling and Differential SAR Interferometry data to show that Vesuvius began to spread onto its sedimentary substratum about 3,600 years ago. Moreover, we model the detected deformation with a solution of the lubrication approximation of the Navier-Stokes equations to show that spreading may continue for about 7,200 years more. Correlation of volcanic spreading with phases of the eruptive activity suggests that Plinian eruptions, which are thought to pose the major hazard, are less likely to occur in the near future.Published1-4partially_ope
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