The new earthquake maps showing potential areas of seismicity induced by human activity indicate north-central and northwestern Oklahoma are areas of some of the highest risk in the U.S. for damaging earthquakes. The U.S. Geological Survey released the first-ever such maps on Monday.
“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. He released the maps and held a news conference. “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.”
The report said the most significant risk from induced earthquakes is in Oklahoma, Kansas, Texas, Colorado, New Mexico and Arkansas and it blamed much of the growth on risk on wastewater injection wells used in the oil and gas industry.
“In the past five years, the USGS has documented high shaking and damage in areas of these six states, mostly from induced earthquakes,” added Petersen. He and others explained the USGS typically updates its earthquake hazard map every five years but with the increase in quakes believed caused by saltwater injection wells, scientists changed their earthquake model for the new report.
The report involves a one-year seismic hazard forecast for 2016 for Central and Easterrn United States that includes contributions from both induced and natural earthquakes.
In addition to northern Oklahoma and southern Kansas, the forecast gave increased risks in the Raton Basin of Colorado and New Mexico, in central Arkansas and in north-central Texas near Dallas.
“Near some areas of active induced earthquakes, hazard is higher than in the 2014 USGS National Seismic Hazard Model by more than a fact of 3,” stated the report. “In some areas, previously observed induced earthquakes hae stopped, so the seismic hazard reverts back to the 2014 model.”
The report said whether it is natural or induced, the increased seismic activity produces high hizard.
“Conversion of grround shaking to seismic intensity indicates that some places in Oklahoma, Kansas, Colorado, New Mexico, Texas and Arrkansas may experience damage if the induced seismicity continues unabated. The chance of having Modified Mercalli Intensity VI or greater (damaging earthquake shaking) is 5-12 percent per year in north-central Oklahoma and southern Kansas, similar to the chance of damage caused by natural earthquakes at sites in parts of Califonia.”
