PhD student wins award for major discovery in rock physics

Chiara Cornelio in the lab directed by Marie Violay, in civil engineering.  © 2020 EPFL

Chiara Cornelio in the lab directed by Marie Violay, in civil engineering. © 2020 EPFL

PhD student Chiara Cornelio has demonstrated that a previously underestimated factor plays a significant role in induced earthquakes caused by hydraulic fracturing.

Earlier this year, Chiara Cornelio, a final-year PhD student in geomechanics at the EDME Doctoral School, collected an Outstanding Student Presentation Award at a major conference in San Francisco, which ran from 9 to 13 December 2019. The award is yet further recognition for Cornelio’s thesis, which marks a significant discovery in her field and has already given rise to an article in a prestigious journal (see below).

Cornelio has spent the last four years based at EPFL’s Laboratory of Experimental Rock Mechanics (LEMR), where she has been studying a phenomenon that could be linked to a process used in geothermal power generation, as well as in oil and shale gas extraction. Known as hydraulic fracturing, it involves the injection of large quantities of fluid under high pressure in underground rock formations – and can sometimes cause earthquakes. Engineers typically use a mixture of 99% water and 1% polymer, which makes the fluid more viscous. (See EPFL News, 16 January 2020.)

Cornelio reproduced the phenomenon in the lab, demonstrating that the viscosity of the fluid has a much greater influence on induced earthquake nucleation and propagation than previously thought. Her discovery, which introduces new physical laws that incorporate this parameter, has major implications for the geothermal power industry in particular.

Cornelio presented her findings at the American Geophysical Union (AGU) conference, where she showed how her experimental tests could be applied on a much larger scale, including in real-life industrial conditions. She is hoping to continue her research at the postdoctoral level.

References

Chiara Cornelio, “Mechanical behavior of lubricated faults during earthquake nucleation and propagation”, thèse sous la direction de Marie Violay, EPFL, 2020.

C. Cornelio, E. Spagnuolo, G. Di Toro, S. Nielsen & M. Violay, Mechanical behaviour of fluid-lubricated faults, Nature Communications, 20 March 2019.