USING UAV-BASED LIDAR FOR HIGHLY DETAILED FAULT SCARP MAPPING AT THE UTAH INGENIOUS GEOTHERMAL RESEARCH SITE

Accurate, detailed Quaternary fault mapping is critical to locating potential blind geothermal systems in the Great Basin region. To increase the accuracy of Quaternary fault mapping at the Lund (Utah) North INGENIOUS site, the Utah Geological Survey collected approximately 10.15 km² of lidar data using a DJI Matrice M300 RTK unmanned aerial vehicle (UAV) with a DJI Zenmuse L1 lidar scanner. For real-time kinematic (RTK) GNSS corrections, we used a cellular data connection to receive corrections from The Utah Reference Network (TURN) GNSS base system. We collected the data in the field over the course of one week, with an additional day of office processing time. We used various software packages for data processing (DJI Terra, GlobalMapper Pro, and ArcPro), resulting in a digital elevation model (DEM) with 0.22 m/pixel resolution. This high-resolution DEM allowed for highly detailed (1:2500 scale or better) mapping of Quaternary-age fault scarps.

The fault crossing the Lund North site is called the Wah Wah Mountains (south end near Lund) fault in the Utah Quaternary Fault and Fold Database. This fault runs approximately 37 km along the southeastern margin of the Wah Wah Mountains, cutting Late-Pleistocene alluvial fans. Previously, 1-m resolution, USGS Quality Level 2, lidar data were used for reconnaissance Quaternary fault mapping at the Lund North site.

We targeted the range front-alluvial fan interface for collecting these data, due to most of the Quaternary-age faulting occurring in this area. This new data allowed us to remap Quaternary-age fault scarps in greater detail. We mapped many previously unrecognized fault step-overs, small zones of distributed faulting, and multiple small (<0.5 m high) fault scarps using the high-resolution DEMs. Overall, the UAV lidar data greatly improved our fault mapping accuracy and will further aid in the characterization of the Lund North site for a potential blind geothermal system.