Fig. 4: Single-component particle slide-hold-slide tests performed in Atomic Force Microscrope (AFM).
From: Feldspar reduces fault frictional healing rate under hydrothermal conditions
a A schematic diagram showing that a feldspar/pyroxene particle attached to a tip slides against feldspar/pyroxene surface. SHS tests are conducted with the same protocol as rotary shear SHS experiments (left inset). Upon resliding after the hold, the lateral force increases abruptly to a peak value and then evolves to a steady-state value (Fss). ΔF is determined by the difference between peak value and steady state value (right inset). b Normalized frictional healing data for the pyroxene-pyroxene contact at RH ~ 80% (upper panel), feldspar-feldspar contact at RH ~ 80% (middle panel) and at RH ~ 5% (lower panel). The blue shaded domain outlines the expected linear trend for ΔF/Fss versus hold time. The pink shaded domain marks the “suppressed” frictional healing effect. Error bar presents the standard deviation of ΔF/Fss (see Methods). c Evolution of the contact stiffness of the system (K) during a 300 s hold for the feldspar-feldspar contact. Inset shows a schematic diagram of the stiffness measurement. The K is the ratio of the normal force variation ΔFn to the vertical displacement change Δz.
