HUTCHINSON, Kan. (AP / KPR) — A series of three earthquakes has rattled portions of south-central Kansas. The Kansas Geological Survey says the strongest measured 3.8 and struck around 2:40 am Monday in Chase County. Another trembler with a 3.6 magnitude was reported around 10 am Monday in Marion County and a third with a magnitude of 2.8 was reported around 10:30 am Sunday in Reno County. The threshold for damage usually starts at 4.0. Kansas began seeing a spike in earthquakes in 2014 that were blamed on wastewater injection wells from oil and gas production. The number of quakes began tapering off after oil prices dropped and new regulations were enacted. The drop in crude oil prices led to less overall activity in the oil patch. At the same time, the Kansas Corporation Commission enacted new rules about waste water injection wells. But a dozen recent reports of earthquakes in Reno County have led the Kansas Corporation Commission to analyze recent injection well activity.