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Monitoring urban subsidence, cavities and landslides by remote sensing

Objective

Problems to be solved
The project MUSCL addresses one of the strategic goals of the 5th framework programme, the fight against major natural and technological hazards. In particular the project is aimed at contributing to the fight against natural hazards, which result from mass movements of unstable mountain slopes and excavations in urban areas. An urgent need exists for widely applicable methods to obtain quantitative data on mass wasting that are required for the assessment and mitigation of the hazards. In the project new techniques, based on Earth observation from space, are developed and validated to improve the detection of hazard zones and to advance the understanding of mass wasting processes.
Scientific objectives and approach
In order to advance the assessment and monitoring of hazards from landslides and buried cavities and to improve the understanding of mass wasting phenomena, advanced remote sensing techniques are introduced. The new information source is space-borne radar interferometry, which allows the measurement of surface displacement at the millimetre to centimetre scale over extended areas. The data sources are radar images of the European Remote Sensing satellites ERS-1 and ERS-2. The interferometric analysis methods will be optimised for the mapping of small displacements in different geological and environmental settings. The information content and application potential of the interferometric products will be validated at selected test sites in the Alpine and Mediterranean region in synergy with optical remote sensing data and with ground-based observations such as seismic profiles and point-based geodetic measurements. The test sites include deep-seated landslides, areas of building collapse related to bury cavities, and subsidence in urban areas due to changes of ground water level. The remote sensing products are integrated with conventional observations to characterise the subsidence and landslide phenomena and to develop methods for synergistic use. The capabilities and constraints of the different methods are assessed and tools for the operational use in risk management are elaborated.
Expected impacts
An integrative system for the detection of hazard zones and the monitoring of precursors to failure due to mass wasting phenomena is developed based on remote sensing and conventional information sources. These developments are guided by the needs of customers, mainly geotechnical companies and regional authorities responsible for hazard management. The project results will provide an improved, objective decision basis for the assessment and warning of geological hazards. The social and economic impact of improved measures for hazard prevention is high in regions that are exposed to landslide hazards and underground instabilities, such as specific zones of the Alpine and Mediterranean regions. In addition, the project contributes to the advancement of the European capacity in Earth observation technologies, enhancing the competitiveness of the Earth observation service providers on the global market. Methods are developed for generating new products from Earth observation data that can be exploited for operational services in geological hazard monitoring and related application areas.
In extension of previous work of the project partners, remote sensing methods and applications were developed or improved to measure and monitor displacements at the Earth’s surface with very high accuracy over extended areas and time periods. The main data source is satellite based imaging radar systems (SAR). The interferometric technique was applied to map motion fields of various type and extent from regional scales down to displacements of individual targets. Millimetric accuracy is achieved for the displacement measurements, which are carried out over repeat intervals ranging from a few weeks to several years. The methods were applied and validated in several test sites in Alpine and Mediterranean regions, including synergistic studies with optical image data and ground-based geophysical and geodetic measurements. In addition, ground-based interferometric SAR (InSAR) methods were further developed in the project, which can be used to monitor the displacement of individual slopes in detail with high temporal and spatial accuracy. The main results are
(i) Improved methods and software to map and monitor fields of surface motion on mountain slopes and subsidence in extended built-up areas using the area-extended InSAR technique based on few SAR images,
(ii) Improved methods to monitor surface motion and subsidence in a wide range of environments, including motion of individual objects, using the Permanent Scatterer Technique based on time series of SAR data,
(iii)Improvements of a ground-based InSAR system to map the displacement of individual slopes, providing complementary capabilities for surveying fast slides and complex small scale slope geometries, and for continuous monitoring,
(iv)Validation of InSAR methods and products in comparison with field data,
(v)Information on application potential and limits of the InSAR tools and products, based on tests in Alpine and Mediterranean regions and in urban areas, and development strategy for operational use in comparison with conventional techniques.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

LEOPOLD-FRANZENS-UNIVERSITAET INNSBRUCK
Address
52,Innrain 52
6020 Innsbruck
Austria

Participants (4)

COMMISSION OF THE EUROPEAN COMMUNITIES
Italy
Address
Via Fermi S/n
21020 Barasso
GEOTEST AG
Switzerland
Address
Birkenstrasse 15
3052 Zollikofen
POLYTECHNIC OF MILAN
Italy
Address
Piazza Leonardo Da Vinci 32
20133 Milano
THE UNIVERSITY OF MILANO
Italy
Address
Via Cicognara 7
20133 Milano