Combination of GPS and InSAR Data for Crustal Deformation Mapping

Zhen Liu, Zheng-Kang Shen, & Cunren Liang

Published August 15, 2016, SCEC Contribution #7011, 2016 SCEC Annual Meeting Poster #140

We are developing an approach to integrate GPS and InSAR data to generate 3-dimensional crustal motion map. Point-based discrete GPS measurements are first interpolated to produce continuous 3-D vector map at common grids covered by the InSAR data, based on an algorithm of Shen et al. [2015] that takes into account GPS station distance, network density and configuration for data weighting. A Gaussian distance weighting function and a Voronoi cell spatial weighting function are used in the interpolation, the amount of weighting and degree of smoothing can be spatially variable and optimally determined based on in situ data strength. At the locations where both InSAR and interpolated GPS data are available, we solve for 3-D velocity field using a weighted least square method. For the interpolated GPS data, we re-estimate uncertainties by adopting a uniform smoothing to ensure that the uncertainty estimates are not biased by uneven degree of smoothing. We investigate the effects of two adjustable parameters (total weight of the site weighting functions and spatial smoothing distance) on resultant uncertainty estimates of the interpolated velocity field and test the method using line-of-sight velocity from selected InSAR tracks in southern California and a combination of continuous and campaign GPS data. In addition, we present initial results of imaging crustal deformation using new satellite sensor data such as ALOS-2 ScanSAR. We show that it is crucial to correct ionospheric noise source for L-band SAR data in order to get accurate measurement of crustal motion induced by both tectonic and non-tectonic sources.

Citation
Liu, Z., Shen, Z., & Liang, C. (2016, 08). Combination of GPS and InSAR Data for Crustal Deformation Mapping. Poster Presentation at 2016 SCEC Annual Meeting.

Related Projects & Working Groups
Tectonic Geodesy