Fig. 5: Schmidt hammer measurements across alteration classes.

A Distribution of all Schmidt hammer measurement sites across the field area, black boxes correspond to close-up views in (B–D). B Close-up of a sub-section of the CFZ representing the sharp transition from high to low Schmidt values as the A-A’ transect crosses into altered territories (see also Supplementary Fig. 1). C Close-up of measurement locations on the north flank, with the black line indicating the elevation profile shown in (D). D Measurement locations on the south flank, with the black line marking the elevation profile shown in (E). E Elevation profile of the north flank (black line) with overlying Schmidt rebound value locations. Schmidt measurements are color-coded to indicate relative rock strength: Very Strong, Strong, Moderate, Weak, and Very Weak. F Elevation profile of the south flank (black line) with corresponding Schmidt hammer measurements, similarly color-coded by relative rock strengths.