31 research outputs found
Frictional Aging of SingleâAsperity Nanoindentation Contacts in Quartz and Calcite
Abstract The evolution of fault friction during the interseismic period affects the mechanics of a future earthquake on the same fault patch. Frictional aging has been previously tied to timeâdependent contact area growth through observations made on rock analogs. However, our understanding of the processes that control frictional aging is limited and is dependent on experiments that explore only numerous mechanisms. We conduct slideâholdâslide experiments with a dualâaxis nanoindenter on singleâcrystal surfaces of quartz and calcite. Our results show that frictional aging in diamondâquartz contacts is independent of time and contact area, in stark contradiction to past experiments done on quartzâquartz contacts in rocks. Diamondâcalcite contacts show modest frictional aging, but still well below previous reported values from calciteâcalcite contacts. These results suggest that frictional aging of likeâonâlike minerals may be of chemical origin, as suggested in recent studies with atomic force microscopy and molecular dynamics simulations