Due to the volume of toxic fluid left underground from hydraulic fracturing activities, Southern Illinoisans are at risk for aquifer contamination when natural or man-made earthquakes occur in Southern Illinois.
There are two major earthquake fault zones in the region–the New Madrid Seismic Zone and the Wabash Valley Seismic Zone–and other earthquake faults as well–the Cottage Grove Fault and the Olmstead Fault. In addition, Southern Illinois is covered in smaller faults called “swarms.”
Southern Illinois has a high risk of seismic activity. Even small seismic events produce changes in groundwater. According to this report from the Department of Geography and Environmental Resources in the Graduate School of Southern Illinois University Carbondale, May 2011, by Sarah E. Waggoner, entitled
groundwater changes due to earthquakes are readily shown to occur in seismically active areas.
“Earthquakes generated from the use of hydraulic fracturing techniques, and/or use of high pressure injection wells, are occurring at an alarming rate throughout the United States, and around the world, due to increases in hydrocarbon exploration and recovery. While the link between earthquakes and natural gas and oil production is still debated, earthquake changes to groundwater chemistry are clear.”
“Two known earthquake swarms, each having repetitive, small earthquake events, occurred in an intraplate setting in Faulkner County, Arkansas. Testing for groundwater chemical changes related to the timing of earthquake events and total energy released show that small earthquakes indeed create changes to groundwater chemistry most probably due to fluid intrusion from deep, chloride, calcium, and magnesium rich waters.”
“Roeloffs (2003) concluded in her study area that distance to the earthquake did not matter as critically as once thought because some wells responded the same way regardless of distance to epicenter and that wells can respond with both increases in water levels and decreases in water levels and it was a function of the particular well. King et al. (2006) verified Roeloffs (2003) findings, as responses were similar over time regardless of location or distance to the event. Liu et al. (1989) observed that some wells are more sensitive and these sensitive wells reacted more to general earth strains like tidal pulls. “