Earthquake shakes Boulder City before sunrise

A 2.8-magnitude earthquake woke up Boulder City residents early Monday morning.

According to the U.S. Geological Survey, the earthquake occurred at 5:38 a.m. just southeast of the city.

Residents described loud noises and tremors, which were also felt in Henderson.

“It really sounded more like an explosion,” said Boulder City resident Steve Andrascik. “I didn’t know if it was an earthquake or the the house next door exploded.”

“It shook the windows, and I didn’t know what was happening,” he said. “It was unsettling.”

Ken Smith, seismic network manager at the Nevada Seismological Laboratory at the University of Nevada, Reno, said that the initial wave, called a P-wave, often produces a booming noise.

The laboratory studies the state’s earthquake activity.

“It’s not unusual for people to hear them before they feel them,” he said.

But a magnitude 2.8 earthquake is not too serious. The 1906 quake that upset San Francisco is traditionally thought to have been magnitude 8.3.

Smith explained that the quake may have seemed bigger because Boulder City sits on top of a pretty thick amount of sediment.

“Geology affects how it feels,” he said.

According to the seismological laboratory, Nevada has thousands of earthquakes too small to feel each year. A quake strong enough to do damage to a populated area happens every three years on average.

“People should always be aware of that,” Smith said.

Seismologists have found active fault lines in every part of Nevada and at the base of nearly every mountain range, but it is more likely that major earthquakes will occur in the northern parts of the state.

According to U.S. Geological Survey records, the largest quake in Nevada happened in 1915, when a magnitude 7.1 earthquake struck Pleasant Valley, north of Carson City.

Two recent major Nevada earthquakes occurred in 2008. A magnitude 6 quake shook the area around Wells, west of Elko, on Feb. 21. A magnitude 4.7 quake hit just west of Reno on April 26.

There is a very small chance that another earthquake will occur within the next five days, between 3 and 6 percent.

Contact reporter Wesley Juhl at wjuhl@reviewjournal.com and (702) 383-0381. Follow him on Twitter @WesJuhl.