Carbon sequestration, enhanced oil and gas recovery, and geothermal energy production all involve injecting large volumes of fluid into underground reservoirs. A major concern for all of these technologies is the risk that injection-induced pressurization could trigger seismicity by fracturing reservoir rocks or causing faults to slip. Laboratory experiments are necessary to better understand these processes, but it isn’t clear that the physics of a geological-scale seismic event can be captured in a laboratory-scale experiment.
Now, Jordi Baró and collaborators have shown that several fundamental laws describing the statistics of natural earthquakes are reproduced in the lab during the failure of a porous material. They did so by compressing a piece of rock-like, porous ceramic and listening for seismic events as it was slowly crushed. They found that the waiting time between events followed the same power law distribution predicted by Omori’s Law for earthquakes. Although further study is necessary, this result is promising for our ability to better understand the risks of earthquakes triggered by human activity.
J. Baró, Á. Corral, X. Illa, A. Planes, E. K. H. Salje, W. Schranz, D. E. Soto-Parra, and E. Vives. Statistical similarity between compression of a porous material and earthquakes. Physical Review Letters, 110:088702, 2013.(http://dx.doi.org/10.1103/PhysRevLett.110.088702)
See also: I. Main. Little earthquakes in the lab. Physics, 6:20, 2013. (http://dx.doi.org/10.1103/Physics.6.20