Underground disposal of waste water produced from oil and natural gas wells has been blamed for triggering thousands of small earthquakes in Oklahoma and a number of other U.S. states since 2009. Heightened seismic activity corresponds closely with the timeframe and location of increased drilling and hydraulic fracturing across the southwest United States, according to the U.S. Geological Survey (“Incorporating induced seismicity in the 2014 United States national seismic hazard model”, 2015). Most tremors have been barely perceptible to humans, but one at Prague in Oklahoma was recorded at magnitude 5.6, enough to cause severe shaking and damage to buildings. The quake swarms have sparked a debate about safety and economic opportunity in states and communities that depend heavily on oil and natural gas production for jobs and income. WASTE WATER INJECTION Most tremors seem to have been caused by re-injection of waste water brought to the surface […]