Frohlich found it plausible that earthquakes in the Cleburne area were triggered by injection in the area.
Other studies across the nation are indicating a possible connection between injection and earthquakes over 3.0 and into damaging magnitudes. Though researchers haven’t reached a consensus on what caused the magnitude 5.6 earthquake in central Oklahoma in November 2011, some scientists believe wastewater injection into a depleted oil field likely played a role.
A Youngstown, Ohio earthquake of magnitude 4.0 in 2011 was linked to injection and regulators shut down a well believed to be responsible.
A University of Memphis researcher found a correlation in 2011 between a series of earthquakes in Arkansas and injection wells.
Researchers have studied possible injection-triggered earthquakes in other areas of Texas, as well.
A study published by Frohlich in 2013 found that “timing of gas injection [in the Cogdell oil field near Snyder] suggests it may have contributed to triggering the recent seismic activity.”
More than 18 earthquakes of a magnitude 3 or greater were reported between 2006 and 2011 in the area of Snyder. Frohlich’s study noted that a prior study of earthquakes between 1975 and 1982 in the area found that water injection to enhance oil production induced a series of earthquakes, as well.
Researchers also studied a magnitude 4.8 earthquake near Fashing and a 4.9 quake near Timpson.
“Quantifying their contribution presents difficult challenges that will require new research into the physics of induced earthquakes and the potential for inducing large-magnitude events,” Ellsworth wrote in a July 2013 review paper in Science Magazine on the topic. “The petroleum industry needs clear requirements for operation, regulators must have a solid scientific basis for those requirements, and the public needs assurance that the regulations are sufficient and being followed.
“The current regulatory frameworks for wastewater disposal wells were designed to protect potable water sources from being contamination and do not address seismic safety,” Ellsworth added. “One consequence is that both the quantity and the timeliness of information on injection volumes and pressures reported to regulatory agencies are far from ideal for managing earthquake risk from injection activities.”