High-Resolution Structure-from-Motion Models of Hydrothermal Sites in the Central Nevada Seismic Belt: Applications in Hydrothermal, Paleoclimate, and Neotectonic Investigations

Abstract

Hot spring travertine and sinter deposits record discharge from hydrothermal systems through evolving hydrothermal, hydrologic, and tectonic regimes. The location and volume of the largest deposits may reflect persistent or particularly robust periods of hydrothermal flow. As part of a broader investigation into the chemical evolution of travertine deposits, we used unoccupied aerial vehicles (UAVs) coupled with high-precision GPS surveys to collect and assemble orthorectified photomosaics and high-resolution digital elevation models (DEMs) using structure-from-motion (SfM) software for eight sites in the northern Central Nevada Seismic Belt. These sites range from large, intrabasin travertine mounds to travertine and sinter deposits offset by Quaternary faults. Some highlights of the research made possible by the acquisition of these topographic datasets include: 1) geomorphic evidence that hydrothermal flow at Hyder Hot Springs has persisted since at least the last highstand of glacial Lake Dixie, 2) documenting the impact of hot spring sinter and hydrothermal alteration on the preservation and morphology of Quaternary fault scarp profiles, 3) mapping the extent of a large extinct travertine deposit in the Stillwater Range, and 4) constraints on the offset of hot spring deposits affected by Quaternary faulting at Kyle Hot Springs. Areas between 0.51 – 1.23 km2 (126-303 acres) were easily acquired with less than half a day of surveying and flying, and models capable of producing orthorectified photomosaics and DEMs with average resolution of 2.5 cm/pixel and 9.7 cm/pixel, respectively, were built on a desktop computer with 1-10 days of processing time. In desert landscapes, the resolution of the resulting DEMs approaches that of bare earth LiDAR datasets at a fraction of the cost, with little to no special permitting in most cases, and with limited preplanning. The imagery and models described herein are freely available from the NSF-EAR-funded data facility OpenTopography (https://portal.opentopography.org/datasets) for use in commercial, academic, and educational applications with proper attribution.