The sound of 10,000 pounds of pressure thundered down on the ground in Arkansas Tuesday, coming from a truck being operated by the U.S. Geological Survey. The truck was operating along a 6-mile stretch of Highway 140 near Lepanto, Arkansas, as part of an earthquake research project.
Robert Williams, part of the USGS team, said the pressure from special equipment on the truck creates shock waves. Those waves are recorded and turned into images that will become a giant ultrasound picture of earthquake activity in the area.
"We are getting a picture of the sub-surface looking at the geology below our feet," Williams said. "We're looking for earthquake faults and structures related to faulting."
Williams said the information collected will tell them a lot about previous quakes in the area and how they affected the ground. The goal is to learn more about quake activity and learn more about how to protect against them.
Local resident Remona McCrary watched with interest as researchers conducted their tests along the roadway in front of her house. She said over the years she's experienced a few tremors.
"I just felt them in the feet," she said. "If I was sitting on the couch, I felt 'em."