Fast and localized temperature measurements during simulated earthquakes
in carbonate rocks
Abstract
The understanding of earthquake physics is hindered by the poor
knowledge of fault strength and temperature evolution during seismic
slip. Experiments reproducing seismic velocity (~1 m/s)
allow us to measure both the evolution of fault strength and the
associated temperature increase due to frictional heating. However,
temperature measurements were performed with techniques having
insufficient spatial and temporal resolution. Here we conduct high
velocity friction experiments on Carrara marble rock samples sheared at
20 MPa normal stress, velocity of 0.3 and 6 m/s, and 20 m of total
displacement. We measure the temperature evolution of the fault surface
at the acquisition rate of 1 kHz and over a spatial resolution of
~40 µm with optical fibers conveying
the infrared radiation to a two-color pyrometer. Temperatures up to 1250
{degree sign}C and low coseismic fault shear strength are compatible
with the activation of grain size dependent viscous creep.