Shallow Rupture Propagation of Pleistocene Earthquakes Along the Hurricane Fault, UT, Revealed by Hematite (U‐Th)/He Thermochronometry and Textures

The material properties and distribution of faults above the seismogenic zone promote or inhibit earthquake rupture propagation. We document depths mechanics fault slip along seismically active Hurricane fault, UT, with scanning transmission electron microscopy hematite (U-Th)/He thermochronometry. Hematite occurs as mm-scale, striated patches on a >10 m2 thin, mirror-like silica surface. textures include bulbous aggregates cataclasite, overlain by crystalline Fe-oxide nanorods an amorphous layer at interface. Textures reflect mechanical, fluid, heat-assisted amorphization silica-rich host rock that weaken dates episodes mineralization between 0.65 0.36 Ma ∼300 m depth. Data illustrate some ruptures repeatedly propagate localized surfaces in shallow crust provide structural property constraints for models slip.