Subsidence with natural and anthropogenic causes can lead to significant damage to structures and infrastructures, and an increase in subsequential hazards such as flooding. Como town, Northern Italy, located adjacent to Lake of Como, has been subjected to significant vertical ground deformations which have been effectively measured from the 1950s through traditional geodetic approaches. This work is tailored to retrospective assessment of the subsidence in Como town through multi-scale integration of historical Geodetic Levelling measurements, Satellite-borne Advance Differential Synthetic Aperture Radar Interferometry (A-DInSAR), and Geospatial techniques. First, historic high precision levelling measurements provided in both urban-scale and building-scale have been used to obtain the vertical ground displacement rates. Then, benefiting from the Synthetic Aperture Radar (SAR) historic data archive acquired between 1992 and 2004 by ERS 1 and 2 satellite mission, the ground deformation in the area has been detected using advanced techniques for DInSAR processing in the SARPROZ software package. Also, Cosmo-SkyMed (CSK) SAR products, from 2010 through 2012 acquired in both ascending and descending tracks with high spatial resolution, have been used for the evaluation of differential settlements in Como cathedral and nearby areas. The accuracy and reliability of the implemented InSAR processing and derived information have been validated using the high precision levelling observations in both urban and building scales. Based on the statistical assessment used in this work, the results showed good consistency between each pair of datasets that were obtained by different techniques. Also, an InSAR coherence-based modification on the original Empirical Bayesian Kriging (EBK) interpolation is proposed, and taking advantage of the availability of precise levelling observations, the reliability of this modification in interpolating the InSAR-derived displacement velocities has been assessed. By using the proposed Coherence-Adaptive EBK, a great enhancement in the estimations was observed, when compared to other spatial interpolations.
La subsidenza per cause naturali e antropiche può comportare danni significativi alle strutture e alle infrastrutture e un aumento dei rischi conseguenti come le inondazioni. La città di Como, nel nord Italia, situata adiacente al Lago di Como, è stata soggetta a significative deformazioni verticali del suolo che sono state effettivamente misurate dagli anni '50 attraverso approcci geodetici tradizionali. Questo lavoro è mirato alla valutazione retrospettiva del cedimento nella città di Como attraverso l'integrazione multi-scala di misurazioni storiche di livellamento geodetico, interferometria radar ad apertura differenziale satellitare (A-DInSAR) e tecniche geospaziali. In primo luogo, per ottenere i tassi di spostamento verticale del suolo sono state utilizzate misurazioni storiche di livellamento ad alta precisione fornite sia su scala urbana che su scala edilizia. Quindi, beneficiando dell'archivio dati storici del radar ad apertura sintetica (SAR) acquisito tra il 1992 e il 2004 dalla missione satellitare ERS 1 e 2, la deformazione del suolo nell'area è stata rilevata utilizzando tecniche avanzate per l'elaborazione DInSAR nel pacchetto software SARPROZ. Inoltre, i prodotti SAR Cosmo-SkyMed (CSK), acquisiti dal 2010 al 2012 sia in salita che in discesa ad alta risoluzione spaziale, sono stati utilizzati per la valutazione degli insediamenti differenziali nel duomo di Como e nelle aree limitrofe. L'accuratezza e l'affidabilità dell'elaborazione InSAR implementata e delle informazioni derivate sono state convalidate utilizzando le osservazioni di livellamento ad alta precisione sia su scala urbana che su scala edilizia. Sulla base della valutazione statistica utilizzata in questo lavoro, i risultati hanno mostrato una buona coerenza tra ciascuna coppia di set di dati ottenuti con tecniche diverse. Inoltre, viene proposta una modifica basata sulla coerenza InSAR sull'interpolazione Empirical Bayesian Kriging (EBK) e, sfruttando la disponibilità di precise osservazioni di livellamento, è stata valutata l'affidabilità di questa modifica nell'interpolazione delle velocità di spostamento derivate da InSAR. Utilizzando la proposta Coherence-Adaptive EBK, è stato osservato un grande miglioramento nelle stime, rispetto ad altre interpolazioni spaziali.
Retrospective study of subsidence in Como town : integration of levelling measurements, DInSAR, and geospatial techniques
ESKANDARI, RASOUL
2021/2022
Abstract
Subsidence with natural and anthropogenic causes can lead to significant damage to structures and infrastructures, and an increase in subsequential hazards such as flooding. Como town, Northern Italy, located adjacent to Lake of Como, has been subjected to significant vertical ground deformations which have been effectively measured from the 1950s through traditional geodetic approaches. This work is tailored to retrospective assessment of the subsidence in Como town through multi-scale integration of historical Geodetic Levelling measurements, Satellite-borne Advance Differential Synthetic Aperture Radar Interferometry (A-DInSAR), and Geospatial techniques. First, historic high precision levelling measurements provided in both urban-scale and building-scale have been used to obtain the vertical ground displacement rates. Then, benefiting from the Synthetic Aperture Radar (SAR) historic data archive acquired between 1992 and 2004 by ERS 1 and 2 satellite mission, the ground deformation in the area has been detected using advanced techniques for DInSAR processing in the SARPROZ software package. Also, Cosmo-SkyMed (CSK) SAR products, from 2010 through 2012 acquired in both ascending and descending tracks with high spatial resolution, have been used for the evaluation of differential settlements in Como cathedral and nearby areas. The accuracy and reliability of the implemented InSAR processing and derived information have been validated using the high precision levelling observations in both urban and building scales. Based on the statistical assessment used in this work, the results showed good consistency between each pair of datasets that were obtained by different techniques. Also, an InSAR coherence-based modification on the original Empirical Bayesian Kriging (EBK) interpolation is proposed, and taking advantage of the availability of precise levelling observations, the reliability of this modification in interpolating the InSAR-derived displacement velocities has been assessed. By using the proposed Coherence-Adaptive EBK, a great enhancement in the estimations was observed, when compared to other spatial interpolations.| File | Dimensione | Formato | |
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R. Eskandari, M. Scaioni [Retrospective Study of Subsidence in Como town Integration of Levelling Measurements, DInSAR, and Geospatial Techniques].pdf
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https://hdl.handle.net/10589/195212