By Briana Mordick, Staff Scientist, Natural Resources Defense Council
The United States Geological Survey (USGS) released a preliminary report yesterday assessing the impact that manmade or “induced” earthquakes caused by oil and gas operations in the Central and Eastern U.S. have on seismic hazard. While their work is not yet final, they were able to conclude that, “potentially induced seismicity greatly increases the seismic hazard in Oklahoma and in the other induced seismicity zones.” In other words, the agency found that underground injection of oil and gas wastewater and possibly hydraulic fracturing are increasing the probability of earthquakes in Oklahoma and other parts of the country with oil and gas activity. A final report is expected from the agency later this year.
This preliminary USGS report comes amidst a flurry of new scientific studies showing conclusively that underground injection of oil and gas wastewater is not only causing earthquakes, it is also leading to a huge increase in the rate of earthquakes across the Central U.S. According to Mark Petersen, Chief of the USGS National Seismic Hazard Modeling Project, “These earthquakes are occurring at a higher rate than ever before and pose a much greater risk to people living nearby.”
In fact, researchers at the USGS previously found that the rate of earthquakes greater than magnitude 3.0 in the central and eastern United States has increased significantly in the past decade, from an average of 21/year from 1967 through 2000 to more than 300 in the years 2010 through 2012, with 188 occurring in 2011 alone.
For decades, the USGS has created National Seismic Hazard Maps, which show earthquake hazard levels across the country. These maps have been crucial to understanding and responding to earthquake hazard and are used to develop things like building codes and emergency preparedness plans. Up until now, however, these maps have only shown the hazards from natural earthquakes. But natural earthquakes are infrequent in places like Prague, Oklahoma, Azle, Texas, Greeley, Colorado, and Youngstown, Ohio–all of which have been rattled over the past several years by earthquakes caused by the oil and gas industry. This means that the maps – and the important decisions that are made with those maps – haven’t accurately reflected the true hazard that these communities face.
Regulators in many of the states where these induced earthquakes are occurring have been skeptical of the connection between the quakes and oil and gas operations, despite science clearly showing a link, and resisted taking action to stop or prevent them. Thankfully that is starting to change. Earlier this week, for example, Oklahoma formally acknowledged the link between earthquakes and oil and gas wastewater injection wells and announced important steps to start addressing them. But some of the operators of the wells themselves still flat out deny that their activities are causing earthquakes, openly defying the science. Both federal and state regulators need to catch up to the science by acknowledging and addressing the risk of induced earthquakes.
With the steep rise in manmade earthquakes caused by the oil and gas industry, USGS recognized the urgent need to update these maps to include the hazard from induced earthquakes. The final maps, which will be available later this year, are a much-needed tool to help protect communities near oil and gas operations.