Operations for production of geothermal power, which involve pumping water into and out of an underground reservoir, has a strong correlation with seismic activity, found a new study.
Emily Brodsky, a geophysicist at the University of California, Santa Cruz, and lead author of the study said: "We show that the earthquake rate in the Salton Sea tracks a combination of the volume of fluid removed from the ground for power generation and the volume of wastewater injected."
The researchers compared earthquake activity with production data for the geothermal power plant, including records of fluid injection and extraction.
The power plant is a "flash-steam facility" which pulls hot water out of the ground, flashes it to steam to run turbines, and recaptures as much water as possible for injection back into the ground.
Due to evaporative losses, less water is pumped back in than is pulled out, so the net effect is fluid extraction.
The researchers tracked the variation in net extraction over time and compared it to seismic activity.
"We found a good correlation between seismicity and net extraction," Brodsky said.
"The correlation was even better when we used a combination of all the information we had on fluid injection and net extraction. The seismicity is clearly tracking the changes in fluid volume in the ground," he added.
The study was recently published in the journal Science.