Land subsidence in coastal environments: Knowledge advance in the Venice coastland by TerraSAR-X PSI

The use of satellite SAR interferometric methods has significantly improved the monitoring of ground movements over the last decades, thus opening new possibilities for a more accurate interpretation of land subsidence and its driving mechanisms. TerraSAR-X has been extensively used to study land subsidence in the Venice Lagoon, Italy, with the aim of quantifying the natural and anthropogenic causes. In this paper, we review and update the main results achieved by three research projects supported by DLR AOs (German Aerospace Center Announcement of Opportunity) and conducted to test the capability of TerraSAR-X PSI (Persistent Scatterer Interferometry) to detect ground movements in the complex physiographic setting of the Venice transitional coastal environment. The investigations have been focused on the historical center of Venice, the lagoon inlets where the MoSE is under construction, salt marshes, and newly built-up areas in the littoral. PSI on stacks of stripmap TerraSAR-X images covering short- to long-time periods (i.e., the years 2008\u20132009, 2008\u20132011 and 2008\u20132013) has proven particularly effective to measure land subsidence in the Venice coastland. The very high spatial resolution (3 m) and the short repeat time interval (11 days) of the TerraSAR-X acquisitions make it possible to investigate ground movements with a detail unavailable in the past. The interferometric products, properly calibrated, allowed for a millimetric vertical accuracy of the land movements at both the regional and local scales, even for short-term analyses, i.e., spanning one year only. The new picture of the land movement resulted from processing TerraSAR-X images has significantly contributed to update the knowledge on the subsidence process at the Venice coast

Combining L- and X-Band SAR interferometry to assess ground displacements in heterogeneous coastal environments: The Po River Delta and Venice Lagoon, Italy

From leveling to SAR-based interferometry, the monitoring of land subsidence in coastal transitional environments significantly improved. However, the simultaneous assessment of the ground movements in these peculiar environments is still challenging. This is due to the presence of relatively small built-up zones and infrastructures, e.g., coastal infrastructures, bridges, and river embankments, within large natural or rural lands, e.g., river deltas, lagoons, and farmland. In this paper we present a multi-band SAR methodology to integrate COSMO-SkyMed and ALOS-PALSAR images. The method consists of a proper combination of the very high-resolution X-band Persistent Scatterer Interferometry (PSI), which achieves high-density and precise measurements on single structures and constructed areas, with L-band Short-Baseline SAR Interferometry (SBAS), properly implemented to raise its effectiveness in retrieving information in vegetated and wet zones. The combined methodology is applied on the Po River Delta and Venice coastland, Northern Italy, using 16 ALOS-PALSAR and 31 COSMO-SkyMed images covering the period between 2007 and 2011. After a proper calibration of the single PSI and SBAS solution using available GPS records, the datasets have been combined at both the regional and local scales. The measured displacements range from ~0 mm/yr down to -35 mm/yr. The results reveal the variable pattern of the subsidence characterizing the more natural and rural environments without losing the accuracy in quantifying the sinking of urban areas and infrastructures. Moreover, they allow improving the interpretation of the natural and anthropogenic processes responsible for the ongoing subsidence

Persistent scatterer interferometry to monitor mining related ground surface deformation for data-driven modelling

The monitoring, interpretation and prediction of gradual ground surface deformation are critical factors in the understanding of earth systems. In many parts of the world, particularly in coastal areas where resources are often easily transportable and where steep cliffs allow access to underlying strata, the patterns of natural ground surface deformation are complicated by mining or extraction activities. To accurately estimate the amount of sea-level rise and Its total affect on, for example, frequency of flooding or salt-water intrusion, the amount of ground surface deformation, either subsidence or uplift, need to be understood in great detail. Ground surface dynamics over an area of contemporary deep mining, IS investigated through two research objectives. A feasibility study of conventional InSAR and Persistent Scatterer InSAR (PSI) in a rural setting was carried out. Rural areas are generally avoided for the application of these techniques for the measurement of gradual ground surface deformation due to the lack of coherence between scenes. The results demonstrate that the new PSI technique significantly outperformed conventional InSAR m the detection of gradual ground surface deformation. However, limitations to the technique were identified in the low density and limited distribution of permanent scatterers. The behaviour of the deformation rate over time appears to be biased to a linear trend. Furthermore, in order to understand the link between underground mining activities and local ground surface response a data-driven model has been developed and evaluated. Based on different mining scenarios, this mode! IS able to estimate the total subsidence in a four dimensional space. It was found that local ground surface deformation can be forecasted accurately, based on an angle of draw and four variables. Five key indicators, which are the extent of die disturbed area, the total period of deformation, the peak rate, the moment of the peak rate and the total deformation, are relevant to understand the impact of underground excavations on the surface and to place it in a wider Earth system

Geomática aplicada al análisis de riesgos geológicos

Tesis por compendio de publicaciones[ES]Esta Tesis Doctoral se ha realizado mediante el formato de compendio de artículos, con objetivos claramente diferenciados y concatenados entre sí con el fin de ampliar el conocimiento sobre la implementación de nuevas metodologías en Geomática Aplicada utilizando información de uso público para la gestión de la peligrosidad natural en la reducción del Riesgo Geológico. Se ha puesto énfasis en hacer conocer a la comunidad los beneficios de analizar los riesgos geológicos con anticipación para identificarlos espacialmente y establecer correcciones estructurales como criterio de prevención, lo que implica elaborar previamente mapas de zonas susceptibles a movimientos en masa, inundaciones, erosión hídrica, mapas sismo-tectónicos-volcánicos y de problemas geotécnicos, a partir de la Geomática Aplicada (Teledetección, Sistemas de Información Geográfica y Modelación Numérica) e información espacial georeferenciada. Se desarrollan en esta Tesis cinco métodos geomáticos aplicados a la reducción del riesgo geológico, validados mediante su aplicación en diferentes riesgos geológicos de varias regiones de Ecuador[EN][EN]This Doctoral Thesis has been carried out through the compendium format of articles, with clearly differentiated and concatenated objectives in order to expand knowledge on the implementation of new methodologies in Applied Geomatics using information of public use for the management of natural hazard in the reduction of Geological Risk. Emphasis has been placed on making the community aware of the benefits of analyzing geological risks in advance to spatially identify them and establish structural corrections as a prevention criterion, which implies preparing previously maps of areas susceptible to mass movements, floods, water erosion, Earthquake-tectonic-volcanic maps and geotechnical problems, from Applied Geomatics (Remote Sensing, Geographic Information Systems and Numerical Modeling) and georeferenced spatial information. Five geomatic methods applied to the reduction of geological risk are developed in this thesis, validated by their application to different geological risks in various regions of Ecuador