UPDATE: July 2 11:40 a.m. According to the USGS, a magnitude 3.8 earthquake was just recorded to have occurred at 11:25 a.m. on July 2, 30 kilometers east southeast of Stapleton, five kilometers below the earth’s surface.
CUSTER COUNTY—If you felt the earth shaking over the weekend it might not have just been Independence Day firework celebrations. Many residents in the Arnold area likely felt another series of earthquakes during the last few days.
According to the United States Geological Survey (USGS), a 4.1 magnitude earthquake was recorded approximately 11:20 p.m. on Friday, June 29. The quake is said to have occurred 35 kilometers (21.7 miles) east southeast of Stapleton, near Arnold.
National Earthquake Information Center (NEIC) geophysicist Paul Caruso told KCNI/KBBN that no significant damage is usually reported with a 4.1, but that you will likely feel it as well as possible aftershocks.
“A magnitude 4.1 is a pretty strong quake for that area and we had two of those over the weekend,” Caruso said. “All earthquakes occur on faults. So that means the rocks underground are moving to accommodate stress and strain. The reason we get aftershocks is because when we have one earthquake in an area it affects all the other faults. Once that fault moves, the other faults nearby can also move because they’ve been disturbed so they want to come back to equilibrium, so we get aftershocks.”
Following Friday night’s earthquake, three earthquakes were recorded early Sunday morning including a 4.1 magnitude earthquake 38 kilometers (23.6 miles) west of Broken Bow at 3:41 a.m.
A 2.7 magnitude earthquake was reported at 2:49 a.m. on July 1 and a 3.7 earthquake occurred at 3:12 a.m., both near Arnold. All of the weekend earthquakes were reported to have occurred between five and 10 kilometers below the earth’s surface according to the USGS.
Caruso said the weekend quakes are likely related. He said aftershocks can occur for years after a larger earthquake with a magnitude of nine, but are less likely with smaller magnitudes. He said central Nebraska residents don’t have to worry.
He said most of the time, damage does not occur unless it is a 4.5 magnitude earthquake or higher.
Most damage and casualties are due to the destruction of larger buildings of more than three stories. Wood-framed houses are generally safe because they are flexible, Caruso said. Most casualties are the result of damage done to rigid buildings, made of cinder blocks or mud in less developed countries.
“That’s one of the big dangers, when an earthquake hits the city–things are falling down. If you’re out on a farm during an earthquake, that’s one of the safest places to be,” Caruso said.
KCNI/KBBN’s Brent Apperson said he and his family felt the Friday night earthquake. “It shook and rattled the house pretty good. Then there were others on Sunday morning, one of which woke us up,” Apperson said.
The weekend activity follows a series of April earthquakes in which seven were recorded near Arnold in the span of just 10 days. (Click here for the April 20 story.)