Nanometre-scale faulting in quartz under an atomic force microscope

• A nanoindentation test was performed on a quartz single crystal.
• A nanometre-scale fault was produced around the indentation two days after the test.
• Precise observation of the fault was performed with an atomic force microscope.
• Displacement and length of the nanometre-scale fault was measured.
• The data supports the linear displacement-length scaling relationship in faults.

We conducted nano-indentation tests of quartz under a load of 294 mN at room temperature and ambient pressure. Using an atomic force microscope, we performed topographic mapping of the indented surface immediately after the nano-indentation test and again 46 h later. Differences in the contour patterns of the two surface topographies reveal that a new fault developed in the quartz specimen while it was secured on the specimen stage of the atomic force microscope between the two mapping times. The fault length is ∼2 μm and the maximum displacement on the fault plane is ∼20 nm. When combined with existing displacement–length data from natural faults, the data suggest that a linear displacement–length scaling relationship can be extrapolated to nanometre-scale faulting.