Joel Johnson

Years participated in RESESS: 2018


An Overview

Major: Geology with Applied Mathematics Minor

Academic Affiliation: Boise State University


Joel was inspired to study the Earth after years of hiking, traveling, and biking, primarily around Boise, Idaho. His interest in remote sensing stems from the efficiency and scope of research that it allows, which he hopes to pursue in graduate school.


Better estimates of creep rate along the Hayward Fault, CA through High-Resolution DEMs and D-InSAR

In recent years the Hayward fault, a right-lateral structure in northern California that parallels the San Andreas in the San Francisco Bay region, has received significant attention, in large part because of the seismic hazard associated with its historic seismicity. Because of the potential for the occurrence of an M6.7-7.0 earthquake along the Hayward fault, considerable effort has been devoted to ongoing monitoring of shallow aseismic creep that occurs on that fault. In addition to ground-based monitoring, differential interferometric synthetic aperture radar (DInSAR) analysis of surface motions has been applied by a number of researchers. Much of that earlier work also used advanced processing techniques, such as persistent scatterer analysis, to compensate for steep topography and vegetation (Schmidt et al., 2005; Tiampo 2013; Shirzaei and Burgmann, 2013). Unlike these studies, we investigate the creeping rate along the Hayward fault using DInSAR with European Space Agency (ESA) Sentinel-1 Single Look Complex (SLCs) and a 3-meter resolution digital elevation model (DEM). The high-resolution DEM increases pixel recovery on the eastern portion of the Hayward fault, which is typically decoherent due to vegetation and topography. We validate the improvement in coherence for those interferograms by processing a single pair using the 3 meter DEM upsampled to 5, 10, 12, 20, and 90 meters. The products are then compared to an interferogram produced using the 30-meter SRTM DEM. We use the JPL ISCE software (Rosen et al., 2011 ) to process all Sentinel 1-A/B Interferometric Wide (IW) SLC scenes covering the Hayward Fault. The resulting interferograms are inverted to create a time series using the JPL GIAnT software (Agram et al., 2013). Given the increase in pixel recovery, time series are produced with good spatial and temporal consistency for both sides of the fault.