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Permanent scatterer InSAR processing: Forsmark

Abstract

It has been speculated that slow, aseismic movement may be occurring along some of the fracture zones crosscutting the Forsmark area. The purpose of this study is to determine if it is possible to measure such movement using dInSAR. Differential SAR Interferometry (DInSAR) is a technique that compares the phases of multiple radar images of an area to measure surface change. The method has the potential to detect millimetric surface deformation along the sensor - target line-of-sight. Differences in phase between two images are easily viewed by combining, or interfering, the two phase-images. In the resulting image, the waves will either reinforce or cancel one another, depending upon the relative phases. The resulting image is called an interferogram and contains concentric bands of colour, or fringes, that are related to topography and/or surface deformation. New algorithms use many images acquired over a long time period to determine the movement history of individual objects, referred to as permanent scatterers. In the current project, standard PSInSAR processing was performed on 40 ERS-1 and ERS-2 scenes. The total area processed is approximately 1,500 km{sup 2}. Slightly less than 20,000 permanent scatterers were identified.The highest densities were obtained along the coast and on the  More>>
Authors:
Dehls, John F [1] 
  1. Geological Survey of Norway, Trondheim (Norway)
Publication Date:
Apr 15, 2006
Product Type:
Technical Report
Report Number:
SKB-R-06-56
Reference Number:
RN06073539; TVI: 0612
Resource Relation:
Other Information: 12 refs., 27 figs., 2 tabs.
Subject:
12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; RADIOACTIVE WASTE DISPOSAL; UNDERGROUND DISPOSAL; SITE CHARACTERIZATION; REMOTE SENSING; GEOLOGIC FRACTURES; RADAR; STRATA MOVEMENT
OSTI ID:
20752508
Research Organizations:
Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden)
Country of Origin:
Sweden
Language:
English
Other Identifying Numbers:
Other: ISSN 1402-3091; TRN: SE0608254
Availability:
Available from: http://www.skb.se/upload/publications/pdf/R-06-56webb.pdf; Commercial reproduction prohibited; OSTI as DE20752508
Submitting Site:
SWD
Size:
29 pages
Announcement Date:
Jul 28, 2006

Citation Formats

Dehls, John F. Permanent scatterer InSAR processing: Forsmark. Sweden: N. p., 2006. Web.
Dehls, John F. Permanent scatterer InSAR processing: Forsmark. Sweden.
Dehls, John F. 2006. "Permanent scatterer InSAR processing: Forsmark." Sweden.
@misc{etde_20752508,
title = {Permanent scatterer InSAR processing: Forsmark}
author = {Dehls, John F}
abstractNote = {It has been speculated that slow, aseismic movement may be occurring along some of the fracture zones crosscutting the Forsmark area. The purpose of this study is to determine if it is possible to measure such movement using dInSAR. Differential SAR Interferometry (DInSAR) is a technique that compares the phases of multiple radar images of an area to measure surface change. The method has the potential to detect millimetric surface deformation along the sensor - target line-of-sight. Differences in phase between two images are easily viewed by combining, or interfering, the two phase-images. In the resulting image, the waves will either reinforce or cancel one another, depending upon the relative phases. The resulting image is called an interferogram and contains concentric bands of colour, or fringes, that are related to topography and/or surface deformation. New algorithms use many images acquired over a long time period to determine the movement history of individual objects, referred to as permanent scatterers. In the current project, standard PSInSAR processing was performed on 40 ERS-1 and ERS-2 scenes. The total area processed is approximately 1,500 km{sup 2}. Slightly less than 20,000 permanent scatterers were identified.The highest densities were obtained along the coast and on the islands, where natural outcrops are more abundant. Two main classes of objects act as permanent scatterers in this area. The first are natural reflectors, such as rocks. The second are man-made reflectors, such as parts of buildings. Numerous local movements were found in the study area, relating to building subsidence, or compaction of anthropogenic fill. The dataset was divided into three groups for analysis, based upon the location of regional lineaments provided by SKB. Both statistical and geostatistical techniques were used. The median velocity of the three blocks did not differ by more than 0.2 mm/yr. This is not considered significant, given the possible magnitude of errors. Surfaces fitted to the three datasets did not reveal any significant spatial patterns related to the fracture zones. Analysis of movement trends across regional lineaments does not support the hypothesis of slow, aseismic vertical movement taking place along these features. Horizontal movement cannot be ruled out. For future monitoring applications, it would be useful to install artificial reflectors in well chosen locations. It would be advantageous if SKB arranged for the acquisition of both ENVISAT and Radarsat images over possible monitoring sites on a regular basis for future analysis.}
place = {Sweden}
year = {2006}
month = {Apr}
}