A light earthquake rattled windows and knocked pictures off the walls of homes in central Utah Saturday morning, but otherwise caused no damage or injuries, officials said.

The temblor occurred at 6:56 a.m. MDT and measured 4.0 on the Richter scale, said Sue Nava, the senior staff seismologist at the University of Utah Seismic Stations.The quake's epicenter was in the Parowan Valley about 12 miles north of the tiny central Utah town of Paragonah, some 230 miles south of Salt Lake, she said.

Iron County officials said the quake was felt but that no damage was reported.

"I called a friend and she said her windows shook and that a couple pictures fell off her wall," said sheriff's dispatcher Sonja Todd.

She said the sheriff's office received a handful of calls from other residents of the sparsely populated area.

Nava said the earthquake was preceded by about 40 "foreshocks" occurring sporadically since Wednesday.

The Richter scale is a gauge of energy released by an earthquake, as measured by the ground motion recorded by a seismograph. Every increase of one digit means ground motion is 10 times greater than the previous number.