Toward the 3-component Crustal Motion Model: Integration of Sentinel-1A SAR interferometry and continuous GPS in the Los Angeles-Western Mojave area

Ekaterina Tymofyeyeva, Homan Lau, & Yuri Fialko

Published August 15, 2016, SCEC Contribution #6976, 2016 SCEC Annual Meeting Poster #139

The new Sentinel-1 mission, launched by the European Space Agency in April 2014, provides extensive coverage at high spatial resolution and frequent revisit intervals, which can dramatically improve measurements of secular and transient deformation in Southern California.
A full description of surface motion requires 3 orthogonal components of the velocity field. InSAR data are limited to the satellite line of sight, and cannot fully resolve 3-dimensional deformation without simplifying assumptions. Continuous GPS measurements are spatially more sparse than full-resolution InSAR data, and suffer from high uncertainties in the vertical direction, but provide robust estimates of horizontal velocities. Together, InSAR and GPS measurements form a complementary data set that can be used to resolve the 3-dimensional deformation field. In this study, we combine data from overlapping Sentinel-1 tracks 71 and 64 with two different look directions, together with the horizontal components of continuous GPS measurements, to estimate the 3-dimensional secular velocity field in the Los Angeles basin and adjacent Mojave desert.
We apply an iterative common point stacking approach to estimate the contribution of the troposphere and ionosphere in the InSAR data, and to isolate low-amplitude deformation signals in our study region over the 2-year time period since the launch of Sentinel-1A. To accommodate the differences in spatial resolution between the InSAR and GPS data sets, we interpolate the North and East continuous GPS measurements over the areas in between the GPS sites. For each InSAR pixel, we use the ascending and descending InSAR data, together with the interpolated North and East GPS components, to solve for the vertical and horizontal components of the velocity field.

Citation
Tymofyeyeva, E., Lau, H., & Fialko, Y. (2016, 08). Toward the 3-component Crustal Motion Model: Integration of Sentinel-1A SAR interferometry and continuous GPS in the Los Angeles-Western Mojave area. Poster Presentation at 2016 SCEC Annual Meeting.

Related Projects & Working Groups
Tectonic Geodesy