New research has claimed that fracking for oil and natural gas can increase the risk of larger earthquakes more than previously thought.
The underground disposal of wastewater that occurs in the process has already been linked to minor earthquakes near to fracking sites.
However, the new study claims that controversial energy extraction technique could cause much larger earthquakes of around magnitude 4 or 5. It found that industrial wastewater disposal weakens pre-existing underground faults through increasing pressure. The study claims this makes certain areas more prone to seismic waves in the wake of a larger, far away quake.
For example, a 4.1 magnitude quake shook the town of Prague, Oklahoma shortly after the 2010 quake in Chile. It links quakes near wastewater injection sites in the US to those as far away as Japan and Chile.
The surge in US oil and gas production by fracking and conventional oil and gas wells is connected to an increase in the frequency of earthquakes in Oklahoma, Arkansas, Ohio, Texas and Colorado.
Nicholas van der Elst, a seismologist from Columbia University and lead author of the study, said, “The fluids are driving the faults to their tipping point.”
Meanwhile, co-author Heather Savage said, “It is already accepted that when we have very large earthquakes seismic waves travel all over the globe, but even though the waves are small when they reach the other side of the world, they still shake faults.
“This can trigger seismicity in seismically active areas such as volcanoes where there is already a high fluid pressure. But this is the first time the same has been recognised for areas with anthropogenically induced high fluid pressure.”
The environmental and social consequences of fracking has led to reluctance in some countries to use such methods. Dutch bank Rabobank recently announced it will not lend money to businesses that deal with unconventional energy extraction.
On Thursday environmental groups in Pennsylvania held anti-fracking rallies.