Oklahoma might not seem like a first choice for a spring break getaway, but sun, warmth, and the outdoors make for a good spring break, even if you have to spend it working. If you’re a seismologist in upstate NY you have to follow where the earthquakes go. I’m thinking of saving up for a tricked out pickup and painting “Earthquake Chasers” on the side, like the tornado hunters we kept running into at gas stations, somewhat unnervingly.
If you’re hearing earthquakes and Oklahoma in the same sentence and getting confused, welcome to the strange new future where OK was the most earthquake-prone state in 2014, more than California. Since 2009 the number of quakes has gone from 1 or 2 felt events a year to 1 or 2 a day; in an animation from the USGS, you can see earthquakes blossom across the entire central portion of the state: http://earthquake.usgs.gov/earthquakes/states/oklahoma/OKeqanimation.php
The largest earthquake so far was a M5.7 near the town of Prague; the rest tend to be around M3 or lower, with a few 4s scattered around. As the earthquakes spread through the north-central region of the state, however, there are larger fault structures that could host higher magnitude events. Over break, my advisor and I installed seismic sensors north of Oklahoma City to record the earthquake swarms as they migrate through the earth. The data we collect will let us investigate the faults involved, the earthquake mechanisms, and their cause.
So where are these earthquakes coming from, you ask? Is it the end of days? Is the earth being rent asunder by our sins??*
The root of the problem is the fossil fuel industry. Oil and gas production creates massive amounts of wastewater; in OK, this is partially from fracking, but the majority actually comes from regular oil and gas wells that extract from water-rich hydrocarbon reservoirs, called dewatering plays. To get rid of it, the wastewater is pumped down into disposal wells like the one pictured above. Adding water on faults makes it easier for them to rupture in an earthquake, creating induced seismicity. The effect has been known for decades – experiments in Colorado in the 1960s and 70s even attempted to control earthquakes through injection tests – but the scale of the problem in OK is unprecedented.
As with all things energy, oil, and science related in this country, there is of course absolutely nothing controversial about the fact that these earthquakes are induced whatsoever.
The close and tangled relationship between University of Oklahoma, the Oklahoma Geologic Survey and companies like Continental and Chesapeake has made the situation politically fraught. The New Yorker just published an article giving a good overview of what exactly has been going on: http://www.newyorker.com/magazine/2015/04/13/weather-underground
Driving around rural OK was an odd experience to adjust to. Seeing the sun consistently for the first time in about 5 months was strange enough, but wells and pump jacks – the contraction pictured above, also called nodding donkeys – are everywhere. Driving around the dirt roads – all straight as an arrow in perpendicular, mile-square blocks – they appear rather sinister, like nodding sentries of a slow-moving alien invasion. While the fields were starting to green up, the trees hadn’t yet, and they were all bare and twisted by the wind. Beyond the oil and gas activity, there was a surprising amount of industrial action in the area: one calcining plant was surrounded by evergreen trees as a wind break, and the combination of the dark trees and the smoke out of the stacks made it look like a dark blotch in the middle of the sunny farmland.
Installing a seismic array mostly involves driving in circles and knocking on doors until you find someone willing to let you dig a hole on their property and drop some equipment in it for several months. Sometimes that can be rough, but not this time. While most of the people we met were friendly and open, with the scale of the quakes that are going on, there was a strong undercurrent of concern. The physical damage may be small to nonexistent so far, but people’s houses are shaking as often as a couple times a day, and they’re worried, particularly because so few people seem to be studying what’s happening.
It will be several months before the data starts to come in from the array we just deployed, but hopefully once it does, I can start getting answers.
*Actual** quotes, though not from anyone in OK.
**Some hyperbole included.