Experimental constraints on dynamic fragmentation as a dissipative process during seismic slip
Abstract
Various fault damage fabrics, from gouge in the principal slip zone to fragmented and pulverized rocks in the fault damage zone, have been attributed to brittle deformation at high strain rates during earthquake rupture. Past experimental work has shown that there exists a critical threshold in stress–strain rate space through which rock failure transitions from failure along a few discrete fracture planes to intense fragmentation. We present new experimental results on Arkansas Novaculite (AN) and Westerly Granite (WG) in which we quantify fracture surface area produced by dynamic fragmentation under uniaxial compressive loading and examine the controls of pre-existing mineral anisotropy on dissipative processes at the microscale. Tests on AN produced substantially greater new fracture surface area (approx. 6.0 m 2 g −1 ) than those on WG (0.07 m 2 g −1 ). Estimates of the portion of energy dissipated into brittle fracture were significant for WG (approx. 5%), but appeared substantial in AN (10% to as much as 40%). The results have important implications for the partitioning of dissipated energy under extreme loading conditions expected during earthquakes and the scaling of high-speed laboratory rock mechanics experiments to natural fault zones.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Aug 21, 2017
- Source ID
- 10.1098/rsta.2016.0002
Entities
People
- Troy Barber
- W. Ashley Griffith
Organizations
- National Science Foundation
- United States Army Research Laboratory