Aretusini Stefano, Núñez-Cascajero Arántzazu, Spagnuolo Elena, Tapetado Alberto, Vázquez Carmen, Di Toro Giulio
Istituto Nazionale di Geofisica e Vulcanologia Roma Italy.
Department of Electronic Technology Universidad Carlos III de Madrid Leganés Spain.
Geophys Res Lett. 2021 May 16;48(9):e2020GL091856. doi: 10.1029/2020GL091856. Epub 2021 May 10.
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 measured the temperature evolution of the fault surface at the acquisition rate of 1 kHz and over a spatial resolution of ∼40 µm with an optical fiber conveying the infrared radiation to a two-color pyrometer. Temperatures up to 1,250°C and low coseismic fault shear strength are compatible with the activation of grain size dependent viscous creep.
对地震物理学的理解因缺乏对地震滑动过程中断层强度和温度演化的了解而受到阻碍。再现地震速度（约1米/秒）的实验使我们能够测量断层强度的演化以及由摩擦加热导致的相关温度升高。然而，温度测量是使用空间和时间分辨率不足的技术进行的。在这里，我们对卡拉拉大理石岩样进行了高速摩擦实验，这些岩样在20兆帕的法向应力、0.3和6米/秒的速度以及20米的总位移下进行剪切。我们以1千赫兹的采集速率和通过将红外辐射传输到双色高温计的光纤在约40微米的空间分辨率下测量了断层面的温度演化。高达1250°C的温度和低同震断层剪切强度与晶粒尺寸依赖性粘性蠕变的激活是相容的。
