An InSAR-GNSS Velocity Field for Iran

Abstract

We present average ground-surface velocities and strain rates for the 1.7 million km2 area of Iran, from the joint inversion of InSAR-derived displacements and GNSS data. We generate interferograms from 7 years of Sentinel-1 radar acquisitions, correct for tropospheric noise using the GACOS system, estimate average velocities using LiCSBAS time-series analysis, tie this into a Eurasia-fixed reference frame, and perform a decomposition to estimate East and Vertical velocities at 500 m spacing. Our InSAR-GNSS velocity fields reveal predominantly diffuse crustal deformation, with localized interseismic strain accumulation along the North Tabriz, Main Kopet Dagh, Main Recent, Sharoud, and Doruneh faults. We observe signals associated with recent groundwater subsidence, co- and postseismic deformation, active salt diaprism, and sediment motion. We derive high-resolution strain rate estimates on a country- and fault-scale, and discuss the difficulties of mapping diffuse strain rates in areas with abundant non-tectonic and anthropogenic signals.