Abstract

In the Northern part of the Apulia Region, between the Lesina Lagoon and the mouth of the Fortore River, isplaced the Pietre Nere (black stones) Point, a very interesting site and the only outcrop of magmatic rocks in thePuglia region and in the whole Adriatic coast of Italy. The excavation of a canal through this area exposed greymicro- and meso-crystalline gypsum with intercalations of black limestones and marls of Upper Triassic age,mantled by loose sandy Quaternary deposits.The gypsum bedrock shows a high density of cavities, either dissolutional conduits or voids related to gravitationalcollapse processes. Starting from about 1970, a wide new touristic settlement has been built over the area, whichin turn, starting from about 1990, began to suffer for the increasing formation of sinkholes.Several interpretations have been proposed to explain the outcrops of Triassic evaporites that occur in the PietreNere Point area, previously buried by a sequence several kilometres thick of Mesozoic rocks: diapirism; pushingupwards by compressional tectonics; both halokinesis and tectonic deformation.The presence of the sinkholes and of the karst reactivation leads to the demand of a monitoring system, for thedetection of vertical displacements over a large area.Thanks to the ability of radar systems to operate in all weather conditions, day or night, and the possibilityof accurately measuring small surface deformations (changes in altitude of a few millimeters), SAR (syntheticaperture radar) differential interferometry (DInSAR) is an ideal technique for detecting and monitoring grounddeformation phenomena (subsidence, faults, landslides, etc.) over vast areas. As an evolution of DInSAR,persistent scatterers interferometry (PSI) [1] allows to follow millimetric movements of stable objects (mainlybuilding and man-made features) present on the Earth surface through time, studying the interferometric responseof such objects along series of SAR acquisitions.We used data from the ASAR sensor onboard the European Space Agency's ENVISAT satellite, from bothascending (34 acquisitions) and descending (28 acquisitions) geometry, covering a total time interval from May2003 to December 2009.Data were processed with a combination of open-source and in-house developed software [2] in order to extractrelevant information about mean velocities of stable points located on the Lesina Marina area.Relying on the relatively smooth nature of the investigated phenomenon, and assuming negligible north-southmovements, as justified by the overall geometry of the site geomorphological units, information coming fromascending and descending geometries was interpolated over a common georeferenced grid, then combined toobtain vertical and horizontal (east-west) velocity components.We observe PS objects undergoing uplift displacements in both ascending and descending data, with uplift ratesdecreasing in a roughly W-SW direction

Autore Pugliese

• Refice Alberto , Bovenga Fabio , Pasquariello Guido

Tutti gli autori

• A. Refice ; F. Bovenga ; G. Pasquariello ; D. Denora ; M.D. Fidelibus; G. Spilotro

Titolo volume/Rivista

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Anno di pubblicazione

2011

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Numero di citazioni Wos

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Settori ERC

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Codici ASJC

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