MAPPING PISGAH CRATER LAVA FIELDS WITH DRONE-BASED PHOTOGRAMMETRY

High-resolution topographic data are invaluable for a wide variety of surfical geology applications. The present study, conducted near Pisgah Crater in the central Mojave Desert, is our department’s inaugural use of drones to map volcanic features. We used a DJI M30 drone as well as a Matrice 300 RTK drone equipped with a Zenmuse P1 sensor to collect geolocated aerial photos of about 33.9 ha of ca. 6 ka basalt flows. These photos were then put into Pix4Dmapper, which uses photogrammetry to achieve 2-10 cm resolution point cloud data with mapped color. A 3D model of the landscape was also generated and 3D printed with a Sovol sv06 FDM 3D printer . These point clouds were then processed in ArcGIS Pro to find slopes and textures of lava flows in the mapped area. We found that flows with grades less than 2% resulted in smooth textures and that flows greater than 2.5% resulted in rough textures. These results were consistent with the current understanding of how the steepness of slopes affects texture. When we compared distances in the generated point cloud with real physical distances measures in the field, the maps were found to be accurate with less than 0.32% distortion. This is within uncertainty of our physical measurements. We found that drones can act as excellent tools for mapping geological landscapes. This project also developed a standing operating procedure for data collection and analysis for future drone-based geologic mapping projects.