It’s no secret that smaller earthquakes have been popping up more in the middle of the country – which is an area that’s usually pretty geologically quiet. Most Scientists say the likelihood of that link is extremely remote, that thousands of fracking and disposal wells operate nationwide without causing earthquakes, and that the relatively shallow depths of these wells mean that any earthquakes that are triggered would be minor. Other scientists’ theories and findings are going to be discussed later this month at a seismology conference.
New technologies have given scientists a much better feel for when the earth shakes. “We’ve been watching the seismicity across most of the country very carefully for a number of years now and one thing we had begun to notice was there was an unusual number of earthquakes occurring in the middle of the country,” said Bill Ellsworth, a seismologist at the U.S. Geological Survey. In fact, the earthquake rates jumped up to more than 6 times of what they normally are.
When scientists took a closer look on where the earthquakes were taking place, they noticed that all were near wastewater wells.
It doesn’t take much to trigger an earthquake and small disturbances can tip the scales, allowing an earthquake to occur. Scientists believe that injecting wastewater into a well raises the pressure of water already trapped in the particles of rock around it.
Since there are small earthquakes in most parts of the country, the evidence linking these earthquakes to wastewater wells is preliminary.