Fracking-triggered earthquakes could get stronger, seismologists say | Al Jazeera America:
Fracking-triggered earthquakes could become stronger over time as more wastewater is injected deep underground, new research suggests. It follows the release of several studies linking hydraulic fracturing directly to increased seismic activity.
Scientists attending the Seismological Society of America (SSA) annual meeting Thursday said that underground disposal of wastewater and fracking likely induce earthquakes by changing the state of stress on existing faults to the point of failure. Most seismic events linked to fracking had been magnitude 3.0 or less.
Researchers had previously believed that such induced earthquakes could not exceed magnitude 5.0. But in 2011, two stronger earthquakes were recorded in heavily drilled areas near Trinidad, Colorado and Prague, Oklahoma.
The larger quakes led researchers brought together by the SSA meeting to believe there may be a cumulative effect and that larger, "outlier" earthquakes could become the norm.
Fracking-triggered earthquakes could get stronger, seismologists say
