The locals call it “incoming,” and some compare the violence of the tremors to living in a war zone.
Others say it’s like having their homes hit by a truck.
The scene is north Texas, home to the Barnett Shale, the largest unconventional gas field in the United States.
There, industry, often touted as the new engine of the U.S. economy, has punctured and fractured the landscape with 17,000 gas wells, as well as thousands of disposal sites to get rid of related toxic waste fluids.
It’s in north Texas where the unconventional gas industry, together with what it calls the “safe and proven” practice of hydraulic fracturing, has been making unconventional, earth-shattering headlines.
In the last three months, the community of Azle, located just northwest of Fort Worth, has suffered a swarm of earthquakes — more than 30 — that has cracked the foundations of the houses, frightened local residents, created sinkholes and raised concerns about property values.
Five quakes in January alone ranged from a magnitude of 2.3 to 3.1. “We’re sitting there, and 11:40, it rumbled right on through the house,” Azle resident Tracy Strickland told KERA news, a public broadcaster in north Texas earlier this month.
“It feels like a truck hits the back of the house, and the whole house just shakes. So, it’s something.”
In many respects the Texas tremors, along with significant earthquakes in Groningen, Holland, offer a glimpse of the geological challenges that will accompany massive drilling activity in northern British Columbia to support the provincial government’s scheme to export unconventional gas to Asia.
After an angry town hall meeting in early January, the Railroad Commission of Texas, the state’s oil and gas regulator, vowed to hire an earthquake specialist to study the phenomenon. It initially denied any connection between tremors and oil and gas activity.
“No disrespect, but this isn’t rocket science here,” Lynda Stokes, the mayor of Reno, Texas (a community near Azle) recently told officials at a 300-strong protest in the state capitol, Austin. “Common sense tells you the wells are playing a big role in all this.”
Quaking and fracking
So, too, does the science.
A string of studies, including one by British Columbia’s Oil and Gas Commission, have not only implicated hydraulic fracturing but the related practice of pumping dirty wastewater deep underground as the cause of unprecedented swarms of earthquakes in Ohio, Arkansas, Oklahoma, Texas, B.C. and even Alberta.
A recent study by the U.S. Geological Survey (USGS) found that the rate of earthquakes greater than a magnitude of three has steadily increased in the U.S. Heartland since 2001, the beginning of the shale gas boom, “culminating in a six-fold increase over 20th century levels in 2011.”
“While the seismicity rate changes described here are almost certainly manmade, it remains to be determined how they are related to either changes in extraction methodologies or the rate of oil and gas production,” concluded the study.
Studies in England, Oklahoma and B.C. have pointedly implicated hydraulic fracturing as earthquake triggers too.
A 2011 fracking operation in the Bowland Shale near Blackpool, England set off 50 minor earthquakes.
In B.C. the industry, which uses three times more water and often at higher pressures than other shale gas formations, set off more than 200 quakes in the Horn River Basin between April 2009 and Dec. 2011.
At least 19 of the quakes ranged between a magnitude of two and three, and one reached a magnitude of 3.8, an event that surprised most scientists.