Three-dimensional geologic map of the San Andreas Fault Zone between Gold Hill and Pinnacles National Park, California (ver. 1.1, October 2026)

This three-dimensional (3D) geologic map of the San Andreas Fault Zone spans approximately 100 kilometers from Gold Hill in the southeast to Pinnacles National Park in the northwest. It was created by assembling eight geologic cross sections derived from geologic mapping, potential-field geophysical models, and petroleum well log descriptions. The resulting 3D geologic map depicts both surface and subsurface interpretations of geologic units, faults, and folds in a model that can be viewed from any perspective and sliced in any direction. Subsurface interpretations in this map are based on geologic mapping completed between 2005 and 2014, existing two-dimensional geologic maps, and existing gravitational anomaly and magnetic anomaly maps.

After completion of the 3D geologic map, kinematic models were created using forward and reverse deformation algorithms in a structural geology modelling software. Kinematic modeling was applied to parts of the map to help better understand the effects of transpressive deformation, and how resulting structures might affect regional seismic hazards. The results of this kinematic modeling yielded insights into the geologic history of the region, including a possible mechanism for the creation of secondary faults, and quantifying the amount of contraction caused by regional compressional stress.