The vibrations you felt on Monday, March 4, weren’t the return of tourists riding ATVs on Moab’s streets.
At 10:22 a.m., a reported 5.3-magnitude earthquake wobbled the Moab area and the surrounding region, with reports coming in to the Moab Sun News that it was felt in by people in Price and Blanding, and Paradox, Colorado.
The University of Utah Seismograph Stations, after the initial 5.3-report, updated the U.S. Geological Survey data on its website to show that the earthquake was a 4.5 magnitude. The quake hit near the Utah-Colorado border at Slick Rock Canyon, about 7 miles southeast of Paradox and just 2.5 miles southwest of Bedrock.
The center says that a total of eight earthquakes measuring 3.0 or greater have occurred within 16 miles of the epicenter since 1962, with Monday’s activity being the largest of those quakes. In Paradox, several residents said the earthquake is the largest they know of to hit the valley.
Moab police said there were no reports of damage related to the tremor.
Moab resident Emily Terris said she had recently visited with friends in Paradox and was on the phone with one when the earthquake happened.
“He started yelling and said things were moving and falling off the walls,” she said.
Denise Perritt, Paradox Valley Charter School principal, said on March 5 that the school has a second inspection planned on Monday, March 11, after the quake caused minor damage to the ceiling tiles and walls. Forty-two students attend the school.
“I know it’s going to sound trite, but it kind of sounded like a train,” Perritt said. “At first, I wondered if it was an explosion. When it continued, I knew it was an earthquake.”
Perritt said teachers directed the students to take cover.
“The students responded so calmly and got under their desks,” Perritt said. “It gives another level of protection if something like a piece of ceiling tile had fallen.”
Plaster walls in an older section of the school building show signs of slight cracking and Perritt said the ceiling tiles “look kind of wavy.”
Perritt said a structural engineer will also inspect two of the modular buildings at the school, which are anchored to the ground with straps and bolts, as a precaution to any future seismic activity.
“If something becomes dislodged and if there is another event, they’re not going to perform as they’re supposed to,” she said.
Grand County School District Superintendent JT Stroder said all principals at the schools in Moab felt the quake, but no damage was reported.
In Paradox Valley, resident Jean Hays and her husband Reed said the earthquake was “very, very loud.”
Hays said she was washing a pan in the kitchen when the tremor shook their house.
“All of a sudden, the refrigerator and freezer looked like they were moving,” she said. “The noise was incredible. A can fell off the shelf in the wash room and it just dawned on me, oh, it’s an earthquake. It lasted about 10 seconds, would be my guess.”
Also feeling the quake were Paradox residents Marty Warner and her husband, Greg Spaulding. The couple own Paradox Produce Company and sell their seasonally grown tomatoes and greens to Moonflower Community Cooperative in Moab.
“I could hear it progressing to the north sides of Paradox Valley,” Warner said. “Past the school and then the post office and I thought I was imagining it, but it sounded like a train underneath the ground.”
Her cats couldn’t get outside fast enough, she said.
“Inside the house everything was shaking,” she said. “When I came outside, I wanted to see if there was any damage and the deer were running all over the place. They were really upset. I have a flock of guinea fowl and they were screaming at the top of their lungs.”
Just before 5:30 p.m. on the day of the earthquake, the U.S. Bureau of Reclamation (USBR) sent a press release saying the quake had a “preliminary magnitude” of 4.1 according to measurements taken at the Paradox Valley Salinity Control Facility near Bedrock.
Employees at the facility also reported feeling the earthquake, said USBR spokesperson Marlon Duke in the press release.
Duke said the measurement of the earthquake was similar in size range to previous “small” earthquakes triggered by the facility’s high-pressure brine injection under the Dolores River. The facility injects highly pressurized, concentrated salt water (brine) into a 16,000-foot well, but the well was not in operation at the time of the earthquake due to routine maintenance.
Operations at the facility will not resume until USBR completes a thorough assessment of the situation, Duke said.
The Paradox Valley Salinity Control Facility substantially benefits downstream water quality in the Colorado River Basin, the USBR press release said, because it helps the U.S. meet treaty obligations with Mexico for allowable salinity levels in the river. Historically, the Dolores River picked up an estimated 205,000 tons of salt annually as it passed through the Paradox Valley.
Since the mid-1990s, much of this salt has been collected by the Paradox Valley Salinity Control Facility in shallow wells along the Dolores River and then injected into deep subsurface geologic formations. The deep well injection program removes about 95,000 tons of salt annually from the Dolores and Colorado rivers, according to USBR.
Warner said residents in Paradox know to expect earthquakes near the facility, but called the quake on Monday “a big one.”
“I have read that they produce about a thousand earthquakes a year,” Warner said. “Sometimes when you’re in bed you can feel a little one. They only last seconds. That’s not every night, but maybe once a year. They never get very strong. The big earthquakes are rare.”
NO CHANGES REPORTED TO FRAGILE ROCK FORMATIONS
In Moab, people who reported feeling the earthquake asked whether there was any impact to the desert’s fragile rock formations.
With heavy rains that moved in to the Moab region on March 2 that broke the daily record from 1941 with a new record 0.44 for the day, a rockfall subsequently closed state Route 128 for the day on Sunday, March 3. The road was reopened that same day after boulders were cleared.
While rockfalls in the desert are common, the activity is typically caused by natural erosion, not human-triggered earthquakes.
At Arches National Park, a section of Landscape Arch fell in 1991 and Wall Arch collapsed in 2008, but no changes to rock formations were reported after Monday’s quake.
“All arches are but temporary features and all will eventually succumb to the forces of gravity and erosion,” the National Park Service wrote in a report about the Wall Arch collapse.
“I always said I would be out of a job if there was ever an earthquake,” said Arches National Park chief maintenance supervisor John Lewis on March 4, adding that he had not heard of any changes to the rock formations within the park following the quake.
Arches National Park Superintendent Kate Cannon said, “As far as we know, none have fallen today.”
On social media, several people commented that they didn’t feel anything, while some people said they felt the tremors in La Sal and Green River, and Grand Junction, Colorado. In Moab, one person commented, “Wall decor was vibrating at Tierra Del Sol.”
The USGS says that people who felt earthquake are encouraged to fill out a survey form through the USGS website at https://tinyurl.com/reportquake or visit https://earthquake.usgs.gov/earthquakes for more information.
Feds investigate high-pressure injection facility near epicenter in Bedrock, Colorado
“I could hear it progressing to the north sides of Paradox Valley … I thought I was imagining it, but it sounded like a train underneath the ground.”