Earthquakes can happen in bone-dry rock, proving we were wrong about needing water to make those deep faults slide.
Geologists previously assumed that water was the essential lubricant required for the 'stick-slip' motion that causes quakes. This discovery shows that extreme heat alone can make dry quartz unstable, meaning earthquakes could happen in much drier environments than we thought.
Frictional instability in quartz gouge at elevated temperature: Beyond the need for water
SSRN · 6552580
The presence and dynamics of aqueous fluids play a critical role in earthquake occurrence. However, some earthquakes occurred even in areas with little aqueous fluid. To investigate the slip stability of dry quartz gouge, velocity-step shear experiments were performed using a double-direct shear apparatus at a normal stress of 10 MPa, temperatures from 30 to 400 ℃ , and sliding velocities from 0.36 µm/s to 39 µm/s. The steady-state friction coefficients at 3.0 µm/s were in the range of 0.619-0.