Topographic metrics and landform classification along the Calaveras fault zone from high resolution 3DEP topography

Madeline F. Schwarz, Celina Driver, Malinda G. Zuckerman, Ramon Arrowsmith, & Chelsea P. Scott

Published September 8, 2024, SCEC Contribution #14028, 2024 SCEC Annual Meeting Poster #111

The Calaveras fault zone exhibits active faulting, landsliding, fluvial modification, and anthropogenic activity. This geomorphology poses a challenge to both human mappers and automatic mapping approaches in identifying and mapping fault traces. In this study, we conduct geomorphometric analysis of the Calaveras fault, Central California, using topographic metrics and landform classifiers applied to 1m lidar from the US Geological Survey 3D Elevation Program (3DEP). Topographic metrics computed from digital elevation models (DEMs) including surface slope, profile curvature, and aspect variance highlight fault traces in the topography and can serve as indicators of relative fault activity by highlighting landform sharpness. Geomorphons and the Pennock landform classification scheme are rule-based approaches to mapping landforms from topography. These schemes work by identifying fundamental landform components in DEMs using pattern recognition based on measures of slope gradients and curvature. We completed detailed fault maps generated by human mappers using a systematized geomorphic mapping approach to determine fault location and confidence from 3DEP topography. We compute slope, curvature, aspect variance, geomorphons, and Pennock landform classes. We assess the surface expression and relative activity of the mapped fault segments by sampling along-strike metrics and landform class values. We expect higher magnitude slope and curvature values along more active fault traces and with traces with higher assigned confidence rankings. Geomorphon and Pennock classification outputs provide insight into how geomorphic indicators of tectonic activity can be distinguished and segmented computationally. With these data and calculated metrics, we will improve our understanding of fault surface expression and segmentation along the Calaveras and how topographic data can be used as inputs into automated mapping models. Future work may include applying segmentation algorithms to compare automated and human mapping performance.

Key Words
Calaveras, fault, mapping, topography, 3DEP, classification

Citation
Schwarz, M. F., Driver, C., Zuckerman, M. G., Arrowsmith, R., & Scott, C. P. (2024, 09). Topographic metrics and landform classification along the Calaveras fault zone from high resolution 3DEP topography. Poster Presentation at 2024 SCEC Annual Meeting.

Related Projects & Working Groups
Earthquake Geology