States Aim to Prepare for and Prevent Human-Induced Earthquakes
For the first time, new U.S. Geological Survey maps identify potential earthquake activity caused by both human-induced and natural events. Prior to this year’s report, USGS maps only outlined natural earthquake hazards. The rise of human-induced earthquakes creates a new hazard zone and many states are trying to prepare for a kind of natural disaster that they haven’t had to deal with in the past.
“By including human-induced events, our assessment of earthquake hazards has significantly increased in parts of the U.S.,” said Mark Petersen, chief of the USGS National Seismic Hazard Mapping Project. “This research also shows that much more of the nation faces a significant chance of having damaging earthquakes over the next year, whether natural or human-induced.”
Human-induced earthquakes are primarily triggered by wastewater from oil and gas production that is disposed of by injecting it into deep underground wells. Oil and gas drilling and wastewater injection wells triggered hundreds of earthquakes in Oklahoma, Texas, Arkansas and Ohio, according to the USGS report. Only 21 earthquakes of magnitude 3 and above occurred in the central and eastern United States between 1973 and 2008. In 2014 alone, there were 659 earthquakes of magnitude 3 and larger, with rates continuing to rise, according to the USGS.
The six states with the most potential hazard from human-induced shaking are Oklahoma, Kansas, Texas, Colorado, New Mexico and Arkansas. About 7 million people live and work in areas with potential for damaging shaking from induced seismicity, according to the report. In a few areas of the central and eastern U.S., the chance of damage from all types of earthquakes is similar to that of natural earthquakes in high-hazard areas of California.
The new hazard model maps potential ground shaking during calendar year 2016. The USGS chose to create a hazard model for 2016, rather than a longer-term forecast, because human-induced earthquake activity can change with time and is influenced by commercial and policy decisions.
The USGS report states that the new map can be used by government officials to make more informed decisions; by emergency response personnel to provide safety information to those who are in potential danger; and by engineers to evaluate earthquake safety of buildings, bridges, pipelines and other important structures. People living in high-risk states can learn how to be prepared for earthquakes through FEMA’s Ready Campaign.
Many states are now regulating wastewater injection in order to limit earthquake hazards. The Oklahoma Corporation Commission, which regulates the oil and gas industry, recently responded to the increase in seismic activity by requesting that producers located in the northwest area of the state reduce by 40 percent the amount of wastewater they dispose. In March, the agency developed a similar plan to reduce the total volume of wastewater disposed in central Oklahoma by 40 percent below 2014 levels over a two month period. In addition, Gov. Mary Fallin directed approximately $1.4 million of emergency funds to addressing triggered earthquakes, which allowed the commission to add additional staff and upgrade technology.
The Kansas Corporation Commission also ordered a reduction of wastewater injections from hydraulic fracturing, also known as fracking, in two counties that border Oklahoma as a result of increased seismic activity reported in the USGS study. Ohio now requires that seismic monitors be installed for fracking operations within three miles of a known fault. If seismic activity above a 1.0 magnitude is detected, the operation must cease, pending an investigation. Well operations would be suspended if a connection between the well and the seismic activity is uncovered. Texas has taken a less restrictive approach and hired a full-time seismologist. The state also requires more information from operators during the permitting process.
Other states, including Vermont and Connecticut, have banned fracking in their states altogether.