The U. S. Geological Survey linked human activity with an increase in earthquakes in parts of the United States. A new report released on Thursday, April 23, 2015 details the research.
The report found industrial operations that inject wastewater into deep wells are linked to an increase in earthquake activity since 2009. The USGS hopes to use this research to develop a forecast for when, where, how many, and how powerful earthquakes will occur over the next year. Currently the computer models predicting this hazard are being tested by the USGS.
Cumulative number of earthquakes with a magnitude of 3.0 or larger in the central and eastern United States, 1973-2014. The rate of earthquakes began to increase starting around 2009 and accelerated in 2013-2014. (high resolution image)
The USGS is mapping the risk in parts of Alabama, Arkansas, Colorado, Kansas, New Mexico, Ohio, Oklahoma, and Texas.
Research has identified 17 areas in the central and eastern United States with increased rates of induced seismicity. Since 2000, several of these areas have experienced high levels of seismicity, with substantial increases since 2009 that continue today. (high resolution image)
According to the USGS the "wastewater that is salty or polluted by chemicals needs to be disposed of in a manner that prevents contaminating freshwater sources. Large volumes of wastewater can result from a variety of processes, such as a byproduct from energy production. Wastewater injection increases the underground pore pressure, which may lubricate nearby faults thereby making earthquakes more likely to occur."
The USGS also found that fracking can occasionally cause localized earthquakes as well.