CONWAY SPRINGS, Kan. (AP) — An earthquake with a preliminary magnitude of 4.8 has shaken parts of Kansas and Oklahoma. The U.S. Geological Survey says the quake struck around 3:40 this (WED) afternoon. It had an epicenter about 8 miles south of Conway Springs, which is a town of about 1,200 people about 30 miles southwest of Wichita. It wasn't immediately clear how much damage the quake may have caused. The southern part of Kansas has been experiencing an upsurge in earthquakes this year. A task force commissioned by Kansas Governor Sam Brownback found there wasn't enough evidence to link the quakes to oil and gas exploration. The panel is recommending more study and the installation of more monitoring stations. Rex Buchanan, the interim director of the Kansas Geological Survey and a member of the task force, says his phone has been ringing off the hook since today's quake. Buchanan says there have been more than 90 - mostly minor - earthquakes in the state since January.