“Revisiting the Vuache Fault Forty Years Later: From Classical Field Geology to High-Resolution LiDAR Morphotectonics”

When this study was completed in 1984 as part of a Geological Engineering Diploma at the University of Geneva, the structural analysis of Vuache Mountain relied exclusively on field observations, classical photogeology, and stereoscopic interpretation of aerial photographs provided by the French National Geographic Institute (IGN).

The primary objective was to understand the origin of the unusual orientation of the Vuache ridge relative to the surrounding Jura folds and to determine the role played by the Vuache Fault in shaping this distinctive morphostructural feature of the Southern Jura.

The investigations conducted in 1984 led to several major conclusions:

• the existence of a main N140°E sinistral strike-slip fault and several associated secondary faults oriented North-Northeast, clearly visible on the eastern slope of the Vuache Mountain;

- the polyphase character of this structure;

- the occurrence of superficial deformation features typical of strike-slip shear zones;

- the presence of “en-echelon” folds, Riedel fractures, and sigmoidal structures;

- the interpretation of Vuache Mountain as a tectonic landform directly controlled by a deep-seated strike-slip fault.

Forty years later, the availability of high-resolution LiDAR-derived digital elevation models provides an opportunity to reassess these hypotheses with a level of detail that was unimaginable in 1984.