Local scientists say even though Thursday's rock slide near Palisade was not caused by an earthquake, it did register on the Richter Scale.

Dave Wolny, faculty member in the Geology Department at Colorado Mesa University, says it was strictly a rock-fall caused by gravity. He says it only registered between 1.2 and 1.5 on the Richter Scale at CMU's seismometer.

Wolny also describes the difference between a rock slide and an actual earthquake.

"It's the way in which the event starts. If you roll a rock down a hill, it kind of starts out slow and gains speed," he explained. "The way the Earth reacts to that, it crescendos upwards as opposed to if we bump over here to our real earthquake, notice how it starts with a real bang."

Thursday's disturbance was also recorded on a seismometer in Utah.

Wolny says this week's rock slide is much smaller than one in July of 2009 that measured 2.5 on the scale.