Geologists are trying to determine if a recent decrease in earthquakes is tied to a reduction in wastewater disposal associated with oil drilling. The process known as hydraulic fracturing, or "fracking", for oil has slowed since last spring and the number of earthquakes in southern Kansas has also declined. Nick Powell of the Kansas Independent Oil and Gas Association says state regulators placed restrictions on the amount of waste water that could be injected into disposal wells. "They're monitoring that to see if that will help the situation." Powell said. "We'll probably know within the next six months exactly what, if any, effect that has on the seismic activity." Tandis Bidgoli of the Kansas Geological Survey says it appears that injection of massive amounts of waste water underground could be contributing to the dramatic recent increase in earthquakes in the region. But she says it’s too early to know for sure. "We're only talking about a few months of data right now." Bidgoli said. "I think if we step back and look at this over the next year, that would probably be when we could make more definitive correlation." Southern Kansas experienced 67 quakes greater than 3.0 in magnitude in the past year, but only 15 since fracking slowed in April and none in July. Between 1980 and 2010, Kansas recorded an average of one earthquake per year. During 2014, when hydraulic fracturing for oil became widespread, the number increased to 127. The majority of the earthquakes have occurred in Harper and Sumner Counties.