Nevada Earthquake Rattles Utah

Did you feel it? At 7:16 am on Thursday, February 21, an earthquake struck just outside of Wells, Nevada. The quake measured 6.0 on the Richter Scale, and was felt for hundreds of miles around. Here in Salt Lake City, 152 miles away from the epicenter of the quake, people reported feeling some mild shaking. "I woke up because I thought my cats had jumped on to my bed, but when I looked there was no one there. It turns out I was feeling the earthquake," said Salt Lake City resident and UMNH educator Shelli Campbell.

In Wells, however, the quake's impact was much worse. According to news reports, almost every building in town was damaged in some way. Luckily, no one was hurt and only three minor injuries were reported.

What about you? Did you feel anything? If so, the US Geological Survey wants to know! Fill out a report about your experience, and leave us a comment below!

This map shows the center of the quake (star). The colored lines show how intense the quake felt to people in each circled area on the Modified Mercalli Intensity Scale.

Utah Mine Collapses: Caused by a Quake?

This morning, the Deseret Morning News reported that six people may be be trapped in a coal mine near Huntington, UT. Rescuers are searching for the miners, but haven't yet been able to reach them. The miners were trapped when a section of the mine caved in.

As the search continues, scientists are trying to understand what might have caused the incident. Seismograph readings show that close to the mine, there were vibrations in the earth around the time of the cave-in. The jolt measured 3.9 on the Richter Scale.

The hard part is knowing whether there was an earthquake that caused the mine to collapse, or if the collapse itself is what caused the earth to shake.

"Normally, rocks in the Earth's crust are constantly subjected to pressures from all sides. This is called a confining pressure. However, the mining of coal leaves a low pressure zone (empty space). After mining, pressures are still being applied to the rock on all other sides, except at the wall of the tunnel. If the rock is not strong enough to withstand this stress, the wall of the mine tunnel gives way. These "bursts" are well named because there is often no warning and large rocks can be thrown horizontally or vertically, as well as drop from the ceiling during these events. In addition to these relatively small rock bursts, more catastrophic "implosional" failures can also occur on a much larger scale. Sometimes large sections of mines can collapse.

"Mine tremors", rock bursts or mine collapse events, are recorded on seismograph instruments in exactly the same manner that earthquakes are recorded."

-University of Utah Seismograph Stations website

We still don't know what caused today's incident, but the U of U Seismograph Stations say that in the Utah coal belt, about 1/4 of tremors are a result of mining, while 3/4 are natural earthquakes.