Wastewater injection linked to increase in earthquakes

Researchers at the annual meeting of the Seismological Society of America (SSA) have claimed that the increase in earthquakes throughout New Mexico is due to wastewater injection. All of the earthquakes are concentrated in and around the Raton Basin, near wastewater injection wells.

Wastewater injection is how mining companies dispose of the brine and water that is produced through the process of fracking. Water is injected to make new rock fractures as the companies extract the natural gases through fracking. The water is usually stored in porous rocks far underground, near to the fracking sites. Mining companies are currently using this technique in the Raton Basin in order to extract methane from coal-beds.

Justin Rubinstein, a US Geological Survey (USGS) research geologist and lead author of several studies on the Raton Basin, presented findings at the SSA meeting showing that seismic activity has drastically increased since 2001. He said that a significant increase in the use of wastewater injection in 1999 has led to this increase in earthquakes throughout the area.

Between the period of 2001 to 2011 the number of magnitude-3 or larger earthquakes rose to 20 times more than there were between 1970 and 2001. The USGS study also found that there was still a significant increase once foreshocks and aftershocks had been removed from the equation.   

At least two faults have been revealed - due to the earthquakes - to cross the Raton Basin. The earthquakes that occur are concentrated along the length of these faults. The USGS researchers believe that the ruptures along the faults are made more frequent as wastewater injection increases fluid pressure along the faults - making it easier for ruptures to occur.

Wastewater injection has been linked to one of the largest earthquakes to occur in the area. In August 2011 an earthquake in Trinidad, Colorado reached magnitude-5.3, cracking walls and destroying property throughout the historic town.