Profiles of Near‐Surface Rock Mass Strength Across Gradients in Burial, Erosion, and Time

Rock mass strength is recognized as an important control on landscape morphology and evolution. However, the controls rock in mountainous topography remain poorly characterized, part because remains challenging to quantify at spatial scales relevant geomorphology. Here we mechanical properties of masses using subsurface S-wave velocities, Schmidt hammer hardness values, Geological Strength Index (GSI) observations. We produce shallow depth profiles shear intact measured from a hammer, assessment structure surface conditions fractures GSI. apply these techniques Western Transverse Ranges, southern California, USA, where gradients stratigraphic age erosion rate allow us evaluate our methodology. resolve differences 200 kPa ∼5 MPa that appear be related diagenetic changes associated with maximum burial young clastic sedimentary rocks. For rocks same lithologic type, age, inferred histories, smaller (300 kPa–1.5 MPa) positively correlated mean rates. suggest increase increasing reflects decreased residence time weathering zone for ranges experiencing faster fault slip These findings demonstrate up order magnitude variability respect burial, erosion, lithologically similar As such, lithology alone unlikely adequately capture role