Development of a New Laboratory Earthquake Setup Featuring a Paraffin oil-based Gel as Analogue Material

In this study, we present the development of a new experimental setup composed of an analogue fault surrounded by paraffin oil-based gel, which allows us to simulate earthquake-like events in the laboratory. The apparatus is designed to test the possibility of mitigating earthquake-like instabilities using control theory. We present the physical properties of the paraffin oil-based gel as functions of strain rate, strain, and temperature. Our results show a linear relation between the stress and strain up to 30% shear strain, along with a low viscosity at high strain rate. Furthermore, we engineered the frictional properties of the analogue fault using 3D-printed patches placed along its surface. Finally, an experimental earthquake simulation, using the setup, demonstrates a sudden slip event within the gel, propagating at a speed between c_s and √2 c_s, where c_s represents the shear wave velocity of the gel, which is consistent with theoretical and previous experimental results.