Measurements of 3-component, time-dependent deformation using Sentinel-1 SAR interferometry and continuous GPS data

Yuri Fialko, & Ekaterina Tymofyeyeva

Published August 15, 2018, SCEC Contribution #8674, 2018 SCEC Annual Meeting Poster #139

Interferometric Synthetic Aperture Radar (InSAR) data are increasingly used to image deformation due to active faults. Frequent InSAR acquisitions are expected to provide an improved signal to noise ratio for low-amplitude deformation signals. However, we find that increasing number of radar interferograms used in the analysis of surface deformation results in the accumulation of high-frequency spatial noise, which is introduced in the time series analysis due to filtering of the radar phase prior to unwrapping. We propose a method for "unfiltering" the filtered unwrapped radar phase. We demonstrate the feasibility of the proposed method using Sentinel-1 InSAR and Global Positioning System (GPS) data. We combine data collected by Sentinel-1 between 2014-2018 with continuous GPS measurements to calculate the three components of the surface velocity field over the southern San Andreas and San Jacinto fault zones at the resolution of InSAR data (~100 m). We obtain the 3 orthogonal components of surface motion using overlapping InSAR tracks with different look geometries, together with an additional constraint provided by GPS measurements of the local azimuth of the horizontal velocity vector. We estimate both secular velocities and displacement time series. The latter are calculated by combining InSAR time series from different lines of sight with time-dependent azimuths computed using continuous GPS time series at every InSAR epoch. We use CANDIS method [Tymofyeyeva and Fialko, 2015], a technique based on iterative common point stacking, to correct the InSAR data for tropospheric and ionospheric artifacts when calculating secular velocities and time series, and to isolate low-amplitude deformation signals in our study region. This three-component, time-dependent description of surface deformation from a combination of geodetic data sets can be used as part of the SCEC Community Geodetic Model.

Key Words
CGM, InSAR, Sentinel-1, GPS, interseismic, deformation

Citation
Fialko, Y., & Tymofyeyeva, E. (2018, 08). Measurements of 3-component, time-dependent deformation using Sentinel-1 SAR interferometry and continuous GPS data. Poster Presentation at 2018 SCEC Annual Meeting.

Related Projects & Working Groups
Tectonic Geodesy