Science Service System

Summary of Proposal GEO1600

TitleUrban subsidence and change monitoring in the city of Barcelona
Investigator Mallorqui, Jordi J. - Universitat Politecnica de Catalunya (UPC), Signal Theory and Communications
Team MemberNo team members defined
SummaryThe project is focused in the study of the subsidence episodes in the city of Barcelona with known recent activity. The urban subsidence was triggered by different under-ground works carried out, like the tunnels for the high-speed train line and the new L9 underground. In some cases the induced deformation has affected buildings structures producing visible damages.
The research is designed with the following OBJECTIVES:
  • Scientific evaluation of the evolution of urban subsidence with advanced DInSAR techniques employing TerraSAR-X images with different resolutions, incidence angles,ascending and descending orbits and polarizations. The objective is to take advantage of the whole dataset of images available and make a joint processing of them
  • Comparison and synergy between TerraSAR-X results and those derived from Radarsat-2full-pol images covering the same period. Once again is to include all data in a single processing.
  • Improvement in the validation of differential interferometric products in urban scenarios due to the higher resolution and better geocoding of the results with ground-truth measurements.
  • Explore the temporal dynamics of data in a systematic way using Binary Partition Trees towards the change detection monitoring and characterization. It is expected to improve the technique to help on the pixel selection step of the DInSAR processing.
The following actions constitute the METHODOLOGY proposed for this project:
  • The combination in a single processing of data with different resolutions and acquisition geometries makes almost impossible to work in slant-range coordinates. The geocoding of the data to the same grid is a key-step that would require preserving not only the location of the pixel (for point-like scatters) but also its extend in ground-range (for distributed ones). Selected pixels with any of the methods will be geolocated and included in a database for its later joint processing.
  • Development of processing strategies able to deal with pixels with different resolutions or acquisition points of view that can exhibit identical and/or different behaviours.
  • Use the change control monitoring tool to detect pixels and areas stable and coherent along time for its inclusion on the pixel selection step of the DInSAR processing. The algorithm can provide also valuable information of pixels and areas exhibiting partial stability along time
  • Validation of the of the results with in-field visits and ancillary data provided by the civil engineers in charge of the underground works.
The following DATA are required for the fulfillment of the project:
  • TerraSAR-X SLC images acquired in any mode over the area of interest.
  • Precise Orbital data of the acquisitions.
  • In situ measurements:topographical control data, ground deformation data (from extensometer devices, topographical surveying, continuous line ground displacement measurement devices, etc)
  • DEM and detailed ortophotos of the study area.
The main DELIVERABLES of the project are:
  • Ground displacement field maps with the finest resolution to establish the subsidence pattern, its temporal evolution and detect deformations at building level.
  • Estimation of the accuracy of the ground displacements
  • Combined technique with the use of both TerraSAR-X and Radarsat-2images.
  • Analysis of the potential of TerraSAR-X images for Early Warning Systems
  • Changes map

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