ST. GEORGE — A swarm, or cluster, of 24 earthquakes have been recorded Tuesday, the first about 37 miles west-northwest of St. George in Nevada, and the others within about a 10-mile radius of the first, see map inset. The earthquakes have ranged from local magnitude 4.1 at both 8:20 a.m. PST and 6:30 p.m. PST, and various lesser amounts throughout the day with the most recent registering local magnitude 3.2 at 6:38 p.m. PST.
The epicenters of Tuesday’s quakes in the region were in a remote section of Southeastern Nevada near the Utah border. Caliente, Nev. – 24 miles from the first epicenter – is the nearest town with any significant human population. The 2010 U.S. Census lists Caliente’s population at 1,130.
Senior scientist on morning quake
St. George News spoke with Bill Lund, senior scientist with the Utah Geological Survey after the first quake registered.
“It’s unlikely that it did much damage,” Bill Lund, senior scientist from the Utah Geological Survey said. “It didn’t cause any faulting at the surface or anything.”
But, Lund said, if it was one notch up on the earthquake magnitude scale, like St. George’s well-known 1992 magnitude-5 quake, it could do some major damage.
The 1992 quake didn’t rupture the surface but it did create heavy landsliding and rock falls. One of the landslides from this quake destroyed a few homes and a water tank in Springdale.
Faults that contribute to these quakes span throughout the St. George area – specifically in the Hurricane and LaVerkin areas. These faults are capable of producing quakes far larger than a magnitude 4, Lund said.
The size of today’s magnitude 4.1 morning quake, ergo its evening quake as well, while notable is not unusual in this area. In fact, this region gets about one magnitude 4 every one to one and one-half years, Lund said.
About two years ago, a magnitude 4 quake occurred near Cedar City and shook the town. “I thought that somebody had accidentally run into our building with their car,” Lund said, who was in Cedar City at the time. Magnitude-4 quakes are very noticeable especially when you’re near the epicenter.
Basin and range region faults
Quakes are a reminder that the whole Basin and Range region – the western part of Utah through Nevada and into Eastern California – has numerous potentially active faults. However, today’s quakes should not worry anyone. Smaller quakes can be precursors to larger events but the probability is low on this one, Lund said.
The basin and range portion of Utah, Nevada and California is being slowly but inexorably pulled apart, Lund said. That pulling apart puts all the land under a lot of strain. Every once in awhile the strain exceeds the strength of the rock and we have an earthquake.
“This is exactly the kind of earthquake we would expect in this part of the world,” Lund said.
For info on earthquake preparation and more facts about earthquakes in this area click here for Utah’s earthquake handbook.
St. George News Editor-in-Chief Joyce Kuzmanic contributed to this report.
Updated 8:10 p.m. Earthquakes listed as occurring Wednesday corrected to Tuesday, Jan. 28.
- Morning earthquake; Southern Utah is earthquake country
- Clusters of earthquakes NNW of Cedar City, WNW of Enoch
- The Great Utah Shake Out seeks earthquake preparedness
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