Database Development for the Trona Pinnacles Fragile Geologic Features

Andrea Donnellan, Christine A. Goulet, Xiaofeng Meng, Gregory A. Lyzenga, Devin McPhillips, & Savannah C. Devine

Published August 13, 2020, SCEC Contribution #10481, 2020 SCEC Annual Meeting Poster #133

The 2019 Ridgecrest earthquake sequence, which included M6.4 and M7.1 earthquakes on orthogonal fault ruptures, occurred near the Trona Pinnacles. The Tona Pinnacles consist of more than 500 tufa spires located in the Searles Lake Basin, some of which reach as high as 40 m. The Trona Pinnacles are about 4 km from the closest point to the Ridgecrest M7.1 rupture and about 14 km from the epicenter of the earthquakes. Several Tufa spires were damaged in the Ridgecrest earthquake sequence, while others remained intact. We have periodically surveyed the Pinnacles using small UAS (sUAS or drones) targeting the overall structure of the pinnacles as well as details of toppled rocks. Damage sustained by Fragile Geologic Features (FGFs) can help constrain the level of ground motions in the absence of instruments. Priority target spires for detailed data measurements were identified in the field and from photographs. We are able to calculate the volume of rocks using detailed stereo photogrammetry. We have also conducted several surveys of the region before and after a M5.5 aftershock on 3 June 2020 and a M5.8 earthquake north of the northern extent of the M7.1 rupture on 24 June 2020. We will compare point clouds to look for additional toppling of fragile features from these events. We will also develop an html/xml database consistent with the SCEC Precariously Balanced Rocks database to be included as an online tool.

Key Words
Topography, geodesy, precarious, fragile

Citation
Donnellan, A., Goulet, C. A., Meng, X., Lyzenga, G. A., McPhillips, D., & Devine, S. C. (2020, 08). Database Development for the Trona Pinnacles Fragile Geologic Features. Poster Presentation at 2020 SCEC Annual Meeting.

Related Projects & Working Groups
Fault and Rupture Mechanics (FARM)