Controlling earthquake-like instabilities in the laboratory

<p>We perform laboratory experiments of decametric scale using a novel triplet apparatus (Fig. 1) that allows (a) to reproduce earthquake-like instabilities and (b) to prevent them by active fluid pressure adjustment. The dynamic earthquake events are prevented using high-end, robust stabilizing controllers that stabilize the system even in the absence of knowledge about its friction, elasticity and other complex phenomena that are hard to quantify in practice.</p><p>Two scenarios are investigated experimentally. In the first scenario, the system is loaded close to its instability point and then fluid is injected in order to provoke a seismic event. We observe how the controller automatically adjusts the fluid pressure in order to prevent such instabilities and immobilize the system. In the second scenario, the controller adjusts the fluid pressure automatically in order to drive the system in a new stable equilibrium of lower energy in an aseismic manner. Despite the inherent unstable behavior of the system, uncertainties related to friction, elasticity and multiphysics couplings, the earthquake-like events are avoided and controlled. We expect our methodology to inspire earthquake mitigation strategies regarding anthropogenic and/or natural seismicity.</p><p>References</p><p>[1] Stefanou, I. (2019). Controlling Anthropogenic and Natural Seismicity: Insights From Active Stabilization of the Spring&#8208;Slider Model. Journal of Geophysical Research: Solid Earth, 124(8), 8786&#8211;8802. https://doi.org/10.1029/2019JB017847<br>[2] Tzortzopoulos G., Braun P., Stefanou I. (2021), Absorbent Porous Paper Reveals How Earthquakes Could be Mitigated, Geophysical Research Letters 48. https://doi.org/10.1029/2020GL090792.<br>[3] Stefanou, I., Tzortzopoulos, G. (2022). Preventing instabilities and inducing controlled, slow-slip in frictionally unstable systems. Journal of Geophysical Research: Solid Earth. https://doi.org/10.1029/2021JB023410<br>[4] Guti&#233;rrez-Oribio D., Tzortzopoulos G., Stefanou I., Plestan F. (2022). Earthquake Control: An Emerging Application for Robust Control. Theory and Experimental Tests. http://arxiv.org/abs/2203.00296<br>[5] Papachristos, E., Stefanou, I. (2022), Controlling earthquake-like instabilities using artificial intelligence. http://arxiv.org/abs/2104.13180.<br>[6] Guti&#233;rrez-Oribio D., Stefanou I., Plestan F. (2022). Passivity-based Control of a Frictional Underactuated Mechanical System: Application to Earthquake Prevention. https://arxiv.org/abs/2207.07181</p><p>&#160;</p><p><img src="https://contentmanager.copernicus.org/fileStorageProxy.php?f=gnp.a2997edc5cb366298823761/sdaolpUECMynit/32UGE&app=m&a=0&c=948f465512ce46d72e88b65435fd71e6&ct=x&pn=gnp.elif&d=1" alt="" width="198" height="229"></p><p>Fig.1: Experiments of decametric scale using a novel triplet apparatus for preventing earthquake-like instabilities</p>