9 Cenozoic Tectonics in Asia and North America: Linking Processes Across Scales (Posters)

This session invites research integrating geologic, geomorphic, and paleoclimate data to advance understanding on orogenesis, seismic hazards, and global change.

Monday, 18 May 2026
8:00 AM - 5:30 PM
Alvarado D/E

High-resolution drone-based photogrammetry measures of syn-tectonic geomorphic marker deformation in an intracontinental transpressional orogen piedmont, Bumbat nuruu range, western Mongolia

Paper number: 9-2
Program: Technical Sessions
Time: 8:00 AM – 8:00 AM

Authors

Abstract

The Bumbat nuruu range, Zereg Basin of western Mongolia is flanked by an intracontinental transpressional strike-slip system of faults that are actively uplifting and deforming the Mongolian Altai. The western piedmont of this range has an actively rising, thrust fault-cored anticline with well-exposed Neogene growth strata and transverse Quaternary alluvial fans and terraces that can be leveraged to reconstruct a base level fall history, rate of fault slip, and inform seismic hazard models. We take advantage of this natural laboratory to reconstruct topographic profiles along stratigraphic and geomorphic markers and measure tilts of geomorphic surfaces using high-resolution drone-based photogrammetry. A high-resolution digital elevation model (DEM) was generated from aerial images acquired using a Phantom 4 Pro unmanned aerial vehicle (UAV) flown at an altitude of 100 m. The flight missions were designed to ensure high image quality, with 60-70% lateral overlap between flight lines and 75-80% forward overlap along the flight direction with all images captured at a nadir angle of 900. We focused effort on five swaths transverse to the anticline collecting a total of 2962 aerial photographs resulting in a DEM with a spatial resolution of 2.28 cm per pixel and vertical resolution of 4.91 cm per pixel. The DEM was further processed in ArcGIS to generate a hillshade model for the identification and extraction of geological and structural features and an accompanying orthophoto was used to delineate geological units through visual interpretation. The drone-based data is field-verified using hand-held differential GPS surveys that were walked along geomorphic marker surfaces. The resulting topographic profiles indicate that terrace and fan surfaces form in response to upstream knickpoint propagation following near instantaneous base-level fall associated with thrust faulting and surface rupture along the Zereg Basin fault. Coupled with a soil and luminescence-based age model, the tilt rate of the growth strata is ~0.04 degrees/ka and the fault slip rates range from ~0.1 – ~0.3 m/ka, but unconformities argue for unsteady tilting and faulting processes. This study illustrates the utility of high-resolution photogrammetry for producing high-resolution datasets in support of field investigations in remote, active tectonic areas with diverse terrain, that are also poorly understood with respect to their seismic hazards.

Geological Society of America Abstracts with Programs. Vol. 58, No. 4

doi: 10.1130/abs/2026RM-410539

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