Flash weakening of serpentinite at near-seismic slip rates

Dynamic weakening of serpentinite gouges and bare surfaces at seismic slip rates

To investigate differences in the frictional behavior between initially bare rock surfaces of serpentinite and powdered serpentinite ("gouge") at subseismic to seismic slip rates, we conducted single-velocity step and multiple-velocity step friction experiments on an antigorite-rich and lizardite-rich serpentinite at slip rates (V) from 0.003 m/s to 6.5 m/s, sliding displacements up to 1.6 m, a...

Slip weakening in rocks and analog materials at co-seismic slip rates

Determination of co-seismic slip resistance in earth faults is critical for understanding the magnitude of shear-stress reduction and hence the near-fault acceleration that can occur during earthquakes. Also, knowledge of shear resistance dependency on slip velocity, slip distance, normal stress, and surface roughness is fundamental information for understanding earthquake physics and the energ...

Slip-weakening distance estimated at near-fault stations

Frictional experiments of dolerite at intermediate slip rates with controlled temperature: Rate weakening or temperature weakening?

[1] A rotary shear apparatus has been newly set up in Chiba University which can control the temperature near a sliding surface, Tmeas, up to 1000°C independently from slip rate, V. Frictional experiments at 0.010 m/s, 1 MPa normal stress, and variable Tmeas for dolerite have revealed a remarkable effect of temperature on the friction coefficient, f. With increasing Tmeas, f starts from 0.7 to ...

Seismic potential of weak, near-surface faults revealed at plate tectonic slip rates

The near-surface areas of major faults commonly contain weak, phyllosilicate minerals, which, based on laboratory friction measurements, are assumed to creep stably. However, it is now known that shallow faults can experience tens of meters of earthquake slip and also host slow and transient slip events. Laboratory experiments are generally performed at least two orders of magnitude faster than...