The American Geophysical Union is holding its Fall Meeting in San Francisco this week. The program includes multiple presentations on induced seismicity (a.k.a. earthquakes) caused by oil and gas production activities. Here are some highlights:
- Scientists at the University of Oklahoma, Lamont-Doherty Earth Observatory at Columbia University, and the U.S. Geological Survey are presenting data on a swarm of earthquakes in Oklahoma, including what would be the largest earthquake potentially related to wastewater injection – a magnitude 5.7 quake that struck in 2011. Based on the timing and location of the earthquakes relative to the injection wells and faults, the researchers conclude that these earthquakes were likely caused by fluid injection.
- Scientists at the U.S. Geological Survey are presenting data that a series of earthquakes in the Raton Basin, including a magnitude 5.3 earthquake near Trinidad, CO in 2011, were caused by injection of wastewater from coalbed methane production. The researchers concluded that the rate of occurrence of earthquakes larger than magnitude 3 increased significantly from 2001 to 2011 as compared to the previous three decades, and that the statistical likelihood of this increase occurring naturally is 0.01%. (Scientists from the University of Colorado are presenting the results of another study on the link between these earthquakes and wastewater injection)
These abstracts and many others on the topic of induced seismicity can be found here.
The conclusion that the Oklahoma earthquakes were caused by wastewater injection is particularly troubling, given that the magnitude 5.7 earthquake injured at least two people, destroyed 14 homes, and damaged many more. Even more troubling is that current regulations do nothing to prevent this from happening again. Operators of wells used to inject oil and gas wastewater are not required to take into account seismic risk when deciding where to put the wells or how to operate them.
Even though scientists have known for a long time that injecting fluids underground can cause earthquakes, an increased focus on this issue is revealing that these induced earthquakes may be happening more frequently than previously thought. Regulations for oil and gas wastewater injection wells must be updated to address seismic risk in order to protect the environment and the public.