A small earthquake rattled central Utah early today, but there were no reports of damage or injury. The quake struck at 6:44 a.m. and registered 4.6 on the Richter scale of ground motion, according to the U.S. Geological Survey's National Earthquake Information Service at Golden, Colo. It was an aftershock of an earlier temblor. Initial reports of the quake came from Price, East Carbon and Helper. The quake's epicenter was 34 miles south of Price. The Carbon County sheriff's office said it received numerous calls, and the Emery County sheriff's office also received a few calls from residents asking about the earthquake. The central Utah area was hit by three quakes on Sunday, the largest of which was 5.6 on the Richter scale. The temblors caused minor damage and were followed by about a dozen aftershocks on Monday. Seismologists had said aftershocks could continue through mid-week. The Richter scale is a measure of ground motion as recorded on seismographs. Every increase of one number means a tenfold increase in magnitude. Thus a reading of 4.5 reflects an earthquake 10 times stronger than one of 3.5. An earthquake of 3.5 on the Richter scale can cause slight damage in a populated area and a 4 can cause moderate damage in the local area.