Last year, the state of Texas funded a program to build 22 seismic monitoring stations around the state, in addition to the 17 they already had there. The goal was to record more consistent and objective data about seismic activity. Why Texas? Well there’s been a significant increase in the number of earthquakes there, especially since 2008, when the number of quakes of magnitude 3 or more jumped from one per year to 12 per year.
Why the increase? According to Cliff Frohlich of the Institute for Geophysics at the University of Texas at Austin, it’s been cause by human activity. That activity dates back to the early 20th Century though, and has been caused by all forms of oil and gas operations.
As the methods used to remove oil have changed, they’ve brought with them different causes of earthquakes. Early pumps pulled out out so quickly that the earth would shake as the oil volume dropped. Later systems used water to drive oil up, and pumping that water down there cause seismic activity. New operations create a lot of waste water which is pumped into the ground and causes quakes.
Frohlich took a look at historical data and posed a number of questions to those data, to determine if they were caused by human activity. Things like how close the epicenter was to oil operations, or how close in time, as well as how deep the epicenter was. Only relatively shallow quakes could have been caused by human activity.
Frohlich and his colleagues hope this new information will get the Texas legislature to take the idea of human caused earthquakes more seriously. As recently as last year some state officials maintain that there is no way human activity can cause earthquakes, which isn’t surprising considering how important oil is to the Texas economy. But ignoring the problem won’t make it go away, and could make it worse.