Science & Technology

Whole-Lotta-Shakin': Cache Valley Residents, Aggies Experience Repeated Small Quakes

USU geoscientists Srisharan Shreedharan, Susanne Jänecke discuss recent geo-events and the importance of earthquake preparedness.

By Mary-Ann Muffoletto |

In USU's Geology Building, Geosciences Assistant Professor Srisharan Shreedharan points out a small seismograph bolted to the floor. He was monitoring real-time data from the instrument, when Cache Valley’s magnitude 3.2 earthquake struck Jan. 3.

Using self-constructed hydraulic and pneumatic presses, newly arrived Utah State University geophysicist Srisharan Shreedharan generates experimental earthquakes in the lab.

“Working in a highly controlled environment, I use experimental rock mechanics to study how earthquakes start, propagate and stop,” says the assistant professor in USU’s Department of Geosciences. “The shaking generated doesn’t extend much beyond the width of a table top.”

Real earthquakes, Shreedharan says, are unpredictable — like the magnitude 3.2 shake near Benson, Utah, that jolted the scientist’s attention Tuesday afternoon, Jan. 3, during his first day on the job at USU’s Logan campus.

“All morning I’d been watching data online from Cache Valley’s recent tremors recorded by our department’s small seismograph bolted to the basement floor of the Geology Building,” he says. “I went home for a while and logged on to continue watching.”

In his central Logan house, Shreedharan heard a window rattle and felt the dwelling shake; then noticed a jump in the waves of the on-screen seismograph. Sharpie pens fell from his whiteboard and he later discovered part of a false ceiling drooped from his basement ceiling.

“My first thought was I’d done something to cause the pens to fall, but I soon realized we’d had another quake — quickly confirmed by a glance at a USGS site and messages with colleagues,” he says. “I consider it a lucky welcome to my new position at Utah State.”

The quake Shreedharan experienced, along with the other events, occurred near the rural community of Benson, about 5 miles west of his Logan home. Benson straddles UT-30 (Valley View Highway) and borders Cutler Reservoir on its western edge.

Shreedharan’s departmental colleague Susanne Jänecke says the Benson earthquake series, which started Jan. 1 and, so far, includes 14 events, might be an earthquake swarm. Swarms, she says, are groups of small earthquakes that occur without an early, larger event.

“The quakes have occurred about 3 kilometers east of the Dayton-Oxford fault zone, and about 10 kilometers west of the East Cache fault zone,” says Jänecke, professor in USU geosciences department. “The earthquakes in this series could be within either, neither or both of those fault zones.”

Jänecke and USU undergraduate researcher Nathan Ellis identified a new part of the active Dayton-Oxford fault zone a few years ago, which they described in a 2019 paper presented at a Utah Geological Survey symposium.

“Our work shows the West Cache fault zone has been much more active than the East Cache fault zone in the last 10,000 years,” she says.

Of the recent Benson quakes, Jänecke says most are small microearthquakes, ranging from magnitudes of 1.3 to 3.2 in size.

“Depths are still being worked out and you can view the most recent data at the University of Utah Seismograph Stations website,” she says. “This is a good source for detailed, up-to-date information.”

While no injuries have been reported and property damage appears minimal, Jänecke says the recent Cache Valley events are an important reminder of the region’s earthquake risks.

“Exceptions happen, but swarms rarely precede major seismic events,” she says. “Still, it’s vital to be prepared and the State of Utah offers a number of helpful online resources, along with the statewide Utah ShakeOut event on Thursday, April 20.”

She notes Italy’s 2009 L’Aquila earthquake, in which more than 300 people died, was one of those exceptions.

Jänecke and Shreedharan also encourage Cache Valley residents to report what they experienced during the recent earthquakes to the U.S. Geological Survey’s Earthquake Hazards Program site.

“Citizen seismology provides invaluable data,” Shreedharan says. “Firsthand accounts of what people felt, saw and heard help scientists and emergency planners determine the size of the quake and prepare for future events — what people experience is as important as what’s recorded on a seismograph.”

Jänecke is a featured speaker this spring during the USU College of Science’s Science Unwrapped public outreach program. She presents “Cache Valley’s Ancient Floods and Earthquakes” Friday, April 14, 2023, at 7 p.m. in the Eccles Science Learning Center on campus. Admission is free and all ages are welcome.

Jänecke also created a YouTube video, “Faults & Earthquakes,” to acquaint the public with faults, earthquakes, risks and preparedness. The brief recording premiered at a recent Rock-n-Fossil Day, the Department of Geosciences’ popular annual outreach event. The 2023 event, free and open to all, will be Saturday, Feb. 25, in the Geology Building on the USU Quad.

A graph of data Shreedharan collected from University of Utah Seismograph Stations of Cache Valley's recent quakes. More detailed information, he says, is available at quake.utah.edu.

WRITER

Mary-Ann Muffoletto
Public Relations Specialist
College of Science
435-797-3517
maryann.muffoletto@usu.edu

CONTACT

Susanne Jänecke
Professor
Department of Geosciences
435-797-1273
susanne.janecke@usu.edu


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Logan 92stories Geosciences 65stories

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