Coseismic Three-Dimensional Displacements Determined Using SAR Data: Theory and an Application Test

Abstract

We present a methodology to construct three-dimensional deformation maps using different parameters that can be extracted using SAR data. We apply the methodology using ENVISAT SAR data before and after the December 26 th , 2003 M w 6.6 Bam earthquake in Iran to determine spatial quasi-continuous threedimensional coseismic deformation maps. Two near vertical deformation offset components are computed using Envisat ASAR differential interferometry (DInSAR), while two horizontal deformation offset components are measured using sub-pixel correlation techniques applied to ASAR amplitude images. Using the presented methodology, we combine four unevenly precise independent projections of surface coseismic deformation to obtain the full three-dimensional coseismic deformation field caused by an earthquake. The full 3-D coseismic displacement vector is modeled using elastic deformation models constraining details of the fault geometry and slip distribution at depth. Results from the inversion are interpreted in the framework of the Iranian present-day tectonism. Full exploitation of dense 3-D coseismic surface deformation using SAR data, even for moderate earthquakes, should facilitate distinguishing between different interpretations of the mechanical properties of seismically active areas and within the inherent ambiguity of the geophysical inversion solutions.

Visualizing and interpreting surface displacement patterns on unstable slopes using multi-geometry satellite SAR interferometry (2D InSAR)

“…We reduced the noise-level in all the interferograms by applying a Goldstein filtering technique (Goldstein and Werner, 1998). Pixels with layover were masked out.…”

“…This is not always feasible when studying features such as rockslides displaying complex displacement patterns. Others studies exploit the amplitude part (feature-tracking) of the complex radar backscatter for studying areas with displacement on the order of decimeters (Fialko et al, 2001;Funning et al, 2005;González et al, 2009;Erten et al, 2010). This is not useful for studying creeping processes with displacement on the order of centimeters per year (Hu et al, 2014).…”

3D Co-Seismic Surface Displacements Measured by DInSAR and MAI of the 2017 Sarpol Zahab Earthquake, Mw7.3

“…However, the phase cause phase shifts by atmospheric path delay (Δϕ atm ), the flat earth effect, the contribution from surface deformation (Δϕ def ), the topography (Δϕ topo ), inaccuracies in the orbit state vectors (Δϕ orb ), and other noise contributions (Δϕ noise ). The difference in interferogram phase (ΔΦ) is measured in radians between 0 and 2π [ 18 ]. …”

Detecting Long-Term Deformation of a Loess Landslide from the Phase and Amplitude of Satellite SAR Images: A Retrospective Analysis for the Closure of a Tunnel Event

“…After masking the geometrical distortions (Figure 5), the master image and slave image were registered and clipped, which registers SAR images more accurately and obtains reliable deformation information. Finally, the range and azimuth deformation in the geographic coordinate system was calculated using the POT method [34,61]. In this study, the improved POT method was used to monitor the deformation based on the two ascending images (acquired on 13 January 2016 and 6 February 2016) and the two descending images (acquired on 8 December 2015 and 25 January 2016).…”