The U.S. Geological Survey says a 3.9 magnitude earthquake was recorded early Monday. The epicenter was about 11 miles northwest of Caldwell, which is on the Kansas-Oklahoma state line in Sumner County. Officials say no damage was reported.

A 3.8 magnitude earthquake also shook the same vicinity Dec. 16.

Paul Caruso, a USGS geophysicist, told The Wichita Eagle it’s very unusual to have two earthquakes in a short amount of time in that area.

Small earthquakes in southern Kansas have become more common, with more than two dozen recorded over the past two years. The area has been the site of increased oil and gas drilling since 2011. Scientists disagree on whether that causes the earthquakes.