Earthquakes caused by human activity (such as 'fracking') will now be included in the U.S. Geological Survey's seismic risk maps, the agency said on Monday after a sharp rise in quakes linked to waste water disposal wells used by the oil and gas industry in Oklahoma.
The seismic risk maps are used by emergency management officials as well as major U.S. engineering and design associations to guide how strong to construct buildings.
By including human-induced events, the agency's assessment of earthquake hazards has significantly increased in parts of the U.S.
Some seven million people in the Central and Eastern United States live or work in areas threatened by so-called induced seismicity, and in parts of these regions, the damage caused by earthquakes could be at parity with that seen in high-hazard regions of California.
The agency indicates the states with the greatest risk for hazards associated with induced seismicity are Oklahoma, followed by Kansas, Texas, Colorado, New Mexico and Arkansas.
Oklahoma in 2015 experienced 907 magnitude 3.0 or greater earthquakes, compared with just two of similar magnitude in 2009. In February, an earthquake of a magnitude of 5.1 shook the area around Fairview, Okla., the third strongest recorded in the state.
The disposal of saltwater into wells, part of the process called 'fracking', is a natural byproduct of oil and gas drilling and has been tied to earthquakes.
USDS - Induced Earthquakes Raise Chances of Damaging Shaking in 2016
