Design of a new laboratory earthquake experiment

In this study, we present a new apparatus for creating earthquake-like instabilities in the laboratory and testing earthquake control theories (Stefanou, 2019a; Stefanou & Tzortzopoulos, 2022; Gutiérrez-Oribio et al., 2022). This experimental setup incorporates an analogue fault surrounded by an elastic medium. The frictional properties of the analogue fault are imposed by 3D printing. The elastic medium was chosen such as to have a very low Young's modulus and allow reasonable sampling rates for testing the earthquake control theories, while enabling the upscaling of the results based on appropriate scaling laws.

The apparatus allows the application of a slow, uniform deformation of the elastic medium through a system of pantographs installed at the lateral boundaries of the device. Then, when the critical state is reached, an earthquake-like instability occurs. The slip front and its propagation are measured using digital image correlation. Preliminary results show qualitative similarities with natural seismic slip, as expected.

The next step is to adjust the effective stress over the analogue fault to achieve a controlled slow slip rate of prescribed amplitude, according to our earthquake control theories and compare the results with those from existing, but simpler, experiments we have performed in the past (Gutiérrez-Oribio et al., 2023).