Mon February 24, 2014
How Aquifers Could Trigger Earthquakes in Oklahoma
Originally published on Mon February 24, 2014 2:16 pm
Federal and university seismologists and geophysicists say oil and gas activity is likely driving Oklahoma’s uptick in earthquakes. The phenomenon, known as “induced seismicity,” is linked to waste fluid injection in disposal wells.
And while scientists say this fluid injection can trigger earthquakes, and suspect it’s doing so in Oklahoma, there are other theories as to what else could be contributing to the state’s exponential increase in seismicity.
One emerging theory is that depleted aquifers could trigger earthquakes when they suddenly refill. News 9′s Alex Cameron interviewed Tulsa geologist Jean Antonides:
Antonides says his research shows that aquifers near the location of certain earthquakes had been depleted, through both drought and increased human demand, and then suddenly refilled, through intense and heavy rains.
“When you have rainfall amounts of six inches over a few day period,” Antonides pointed out, “these rainfalls cover a thousand square miles — that’s a lot of weight.”
That much new weight – potentially trillions of tons — if it’s along or across a fault, can be enough to cause an earthquake.
Antonides’ paper lays out evidence that this hydrologic loading could have triggered, not only the Prague earthquake, but last April’s 4.3 magnitude quake in Luther, a 5.8 M quake in Virginia in 2011, and others.
It’s worth noting that Antonides works for an oil and gas company, Tulsa’s New Dominion, which operated a disposal well near the epicenter of the above-referenced Prague earthquake, the 5.6-magnitude temblor that is Oklahoma’s largest ever recorded.
But the state’s official seismic authority, the Oklahoma Geological Survey, says Antonides research, which News9 reports hasn’t been published, is based on sound science. The OGS itself has theorized that the weight of the water that accompanied high lake levels in Lake Arcadia, could have contributed to earthquakes that shook near Jones and Luther in November 2013.
“I think, in some cases,” Holland told us, “there’s really strong evidence that hydrologic loads can trigger earthquakes.”