California Institute of Technology
Seismological Laboratory Division of Geological and Planetary Sciences

People

Heresh Fattahi

Heresh Fattahi

Post Doctoral Scholar in Geophysics

Ph.D., 2015, Geophysics, University of Miami

California Institute of Technology
Seismological Laboratory
1200 E. California Blvd., MS 252-21
So. Mudd Building, Rm 262
Pasadena, CA 91125

Phone: (626) 395-3825
Fax: (626) 564-0715
Email: hfattahi@gps.caltech.edu

Research

My research is focused on the Interferometric Synthetic Aperture Radar (InSAR), and its application for measuring precise ground displacement of solid earth due to the tectonic and non-tectonic forces. The InSAR data can potentially deliver precise ground displacement (mm/yr) over large areas (hundreds of kilometers), enabling us to evaluate the regions with localized strain and the rate of strain accumulation during the interseismic period. The location of the localized strain and the rate of the strain accumulation are crucial information to evaluate the location and magnitude of the future earthquakes. The high spatial resolution of the InSAR data provides a remarkable opportunity for high-resolution strain mapping across the plate boundaries, which helps to better understand how deformation is accommodated across the plate boundaries. Whether the deformation is localized or distributed across the plate boundaries, is essential to understand the fundamental questions regarding the strength of the earth’s crust and lithosphere. The high spatial resolution InSAR data improves our understanding of the near fault deformation, shallow fault creep and aseismic slip of the faults.
InSAR can also detect and measure small ground movements due to the hydrological and magmatic activities or the elastic rebound due to the loading/unloading. The technique can also be used to monitor the small movements of the urban areas and structures or to estimate the velocity of the melting glaciers in the Polar Regions.  
Given the ground (or target) movements as our signal of interest in many InSAR applications, the accuracy of the InSAR measurements of displacement is affected by the different noise components in the data. During the last few years, my research has been mainly focused on the uncertainty of the InSAR measurements due to the geometrical residuals (eg: due to the DEM errors, orbital errors, imperfect geometry in SAR and InSAR processing, etc), tropospheric delay and phase unwrapping errors. More recently I have been working on the precise coregistration of the new Sentinel1 TOPS acquisitions, which require unprecedented accuracies of better than 0.001 pixels.