Fast and Localized Temperature Measurements During Simulated Earthquakes in Carbonate Rocks

The understanding of earthquake physics is hindered by the poor knowledge of fault strength and temperature evolution during seismic slip. Experiments reproducing seismic velocity (similar to 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 measured the temperature evolution of the fault surface at the acquisition rate of 1 kHz and over a spatial resolution of similar to 40 mu m with an optical fiber conveying the infrared radiation to a two-color pyrometer. Temperatures up to 1,250 degrees C and low coseismic fault shear strength are compatible with the activation of grain size dependent viscous creep. Key Points Optical fibers were used to measure temperature evolution during simulated seismic slip Temperatures were up to 1,250 degrees C and compatible with coseismic grain size dependent creep "Frictional work" during simulated seismic slip was mostly dissipated as heat