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| Titel |
Active fault analysis and tectonic setting assessment with SqueeSAR |
| VerfasserIn |
Sara Del Conte, Andrea Tamburini, Alfio Fumagalli, Fabrizio Novali |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250053493
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| Zusammenfassung |
| Surface deformation monitoring can provide evidence of fault activity at the ground surface.
Geodetic measurements (Levelling campaigns, GPS permanent stations) and Satellite
Radar Interferometry are the techniques most widely used to determine surface
displacements. Whatever the surveying technique, the detection of millimetre level surface
deformation is required. While differential synthetic aperture radar (DInSAR) data has
been widely explored in a number of cases for detecting and analyzing surface
faulting, especially in case of seismic events, few are the applications of Persistent
Scatterer Interferometry (PSI) algorithms to tectonic studies. Permanent Scatterer
Techinque (PSInSAR), introduced by POLIMI in the late nineties and subsequently
improved by TRE, and the advanced second generation SqueeSAR analysis, search the
radar image set for targets that consistently reflect radar signals throughout the
entire dataset of images, exploiting both permanently scattering ground targets (PS,
e.g. buildings, pipelines, linear structures, open outcrops etc.) and homogenous
distributed scatterers (DS, e.g. homogeneous ground or scattered outcrops, uncultivated
areas, debris covered areas). Thanks to the high density of measurement points, the
millimetric accuracy of measurements, and the wide spatial coverage, the SqueeSAR
technique is able to measure slow tectonic displacements and represents a useful
tool to detect ground deformation related to crustal faulting over wide areas. The
availability of long time-series archives of images also allows the reconstruction
of the dynamic evolution of the displacement, which is extremely functional to
model deformation fields and to evaluate seismic hazard. Applications of SqueeSAR
analyses aimed at identifying displacements related to fault reactivation induced by
hydrocarbon reservoir exploitation have been recently published. In this paper, a
methodology to be used to extract information on surface deformation fields will
be presented, but, rather than focusing on InSAR algorithms, “post-processing”
activities will be highlighted, and some applications of active fault analysis and
tectonic setting assessment are reported. The proposed methodology consist of:
extraction of easting and vertical components by combining ascending and descending
satellite data-sets, removal of systematic errors and calibration with in situ data,
estimation of the gradient of the displacement field in order to highlight trends and
anomalies and analysis of the temporal evolution of displacement values along
representative cross sections. Moreover, the complementarities of InSAR results with GPS
measurements will be demonstrated through the analysis of selected case studies, e.g.
city of Tunis and the San Francisco Bay Area. Applications of fault identification,
pre-seismic and post-seismic deformation setting analysis and silent slip events (e.g.
Superstition Hills slip event of October 2006) demonstrate that the proposed methodology
can help evaluate fault geometry, identify causative tectonic structures, support
dynamic behaviour interpretation and assess hazard in areas exposed to high seismic
risk. |
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