For those who thought they felt a bit of a shake on Friday morning, it wasn't their imagination.
Two earthquakes, measuring 3.0 and 3.5, rattled through Douglas County at 6:55 and 7:02 a.m., respectively, according to the Nevada Seismological Laboratory at University of Nevada, Reno.
"I felt just a little shake after the last quake," said sheriff's dispatcher Cathy Rhead. "It was so slight that I wondered if it even was an earthquake."
Douglas County sheriff's deputies said they received only one call regarding the quakes, and there were no reports of damage or injuries.
Ken Smith, a UNR seismologist, said the earthquakes were centered in the same area that produced the powerful 5.9 Double Springs Flat quake of 1994, 10 miles southeast of Minden.
The epicenter of Friday's quakes was just north of Topaz Lake, along Highway 395.
"These are only the latest quakes to originate in the area," Smith said. "Some of them have been magnitude 4 or higher, and they're all considered aftershocks of the 1994 quake."
It's not unusual to see this sort of delayed aftershock, said Smith.
"People shouldn't be too worried about the quakes, as they are in the aftershock zone, and relatively minor," Smith said.
"Earthquake damage depends on the magnitude of the quake, proximity to the epicenter and soil conditions. Lake basin homes are more prone to ground-shaking than those on hard rock," Smith said. Though such small quakes as those experienced Friday usually cause no damage, residents near the epicenter should be alert to possible structural damage, Smith said.
The Double Springs Flat area is one of three major fault zones in the Carson Valley, said John Bell of the Nevada Bureau of Mines and Geology.
A series of faults also run between the Gardnerville/Minden area and Carson City, constituting the East Carson Valley fault zone. The Genoa fault zone contains the largest and most active fault in Northern Nevada. According to the NBMG, Nevada is the third most seismically-active state in the nation behind California and Alaska.
The UNR seismology Web site, www.seismo.unr.edu, offers the following earthquake-preparedness tips for pre-, mid- and post-earthquake:
- Have a battery-powered radio, flashlight, drinking water and first-aid kit accessible, along with fresh batteries.
- Know where and how to shut off gas and water lines.
- During an earthquake, if you are indoors, stay indoors, and if you are outdoors, stay outdoors. If indoors, brace yourself in a doorway or under a sturdy piece of furniture. If you are outdoors, stay away from buildings and power lines. Buildings may be highly unstable after an earthquake, so use caution when exiting.
For more information on how to prepare for an earthquake, contact the Nevada Division of Emergency Management at (775) 687-4240.
- The Associated Press contributed to this story.