New Map Highlights the Danger of Man-Made Earthquakes
Every San Franciscan knows what to do when the big one comes. Earthquake preparedness is part of public school curriculums and yearly checkups: Have your go-bag packed and your emergency plan memorized for the next time the San Andreas or the Hayward fault gets frisky. Less prepared for an earthquake, though, are Oklahomans. Which is a problem, because some areas of Oklahoma are at risk of temblors just as damaging as a California quake.
Earthquakes in Oklahoma? Yep: Released today, the US Geological Survey’s earthquake hazard maps show a giant, red “high hazard” blob hovering over northern Oklahoma and southern Kansas.
Historically, that area has experienced only a handful of earthquakes per decade. So what’s to blame for all these new tremors? The oil and gas industry, according to USGS and other seismologists. Those companies inject toxic wastewater thousands of feet into the ground—a cheap way to dispose of the stuff—and scientists have linked those injections to an increase in seismic activity. So this year, for first time ever, the USGS decided to include those human-induced earthquakes in an update to its hazard maps.
The maps provide “hazard information that policy makers can use to make more informed decisions on the effects of earthquakes and provide safer communities in the future,” says Mark Petersen, who heads the USGS’s National Seismic Hazard Mapping Project. “Much more of the nation faces a significant chance of facing damaging earthquakes over the next year.”
The USGS periodically releases seismic hazard maps to show the chance of major shaking from tectonic earthquakes over a 50-year period—the average lifespan of a building. These probabilities are used to determine things like building codes, insurance rates, and land-use planning, especially in earthquake-prone areas like the Bay Area.
But after a huge uptick in oil-and-gas-related earthquakes in central US states, the USGS began compiling seismic and industry data from 2014 and 2015 to project the one-year risk of damage from manmade earthquakes. The result is pretty dramatic in some places: The updated maps show up to a 12 percent probability of earthquake damage in northwestern Oklahoma, the same as Monterey, California, which lies near the San Andreas fault. The USGS estimates over 7 million people live in areas at risk of human-induced earthquake damage, including in Oklahoma City and Dallas.
Before you dive under your desk, keep in mind that damage in most of these cases would look more like cracks in walls and roads than buildings collapsing to the ground. Even so, many people—Oklahomans, especially—have been dealing with structural damage from constant tremors for a few years.
As Rivka Galchen reported in the New Yorker, Oklahoma has been slow to recognize the connection between earthquakes and the disposal of toxic wastewater. (Water-intensive extraction techniques like fracking account for a fraction of human-induced earthquakes, but in general wastewater disposal is much more damaging.) The Oklahoma Corporation Commission did not regulate where and how oil and gas wastewater was injected, even while states like Kansas were seeing results from changing their injection policies.
Last April, Oklahoma governor Mary Fallin finally recognized the the research showing that injection wells cause earthquakes, and last year the commission began shutting down disposal wells and mandating reductions in wastewater injection in some areas. But still, the earthquake problem won’t be going away soon. Just in the past week, Oklahoma has experienced eight earthquakes with a magnitude over 3.0.
“The work of scientists has established that disposal wells are creating earthquakes,” says Mark Zoback, a geophysicist at Stanford University whose research was used by the USGS. “Now the question is how do we deal with it.” One answer: Definitely not by ignoring it.