A seismology sensor picked up an explosion that shook the ground south of Kennewick at 8:47 a.m. Thursday morning.
The Pacific Northwest Seismic Network detected the ground rumbling along a vacant piece of land in Finley near the intersection of Highway 397 and Interstate 82. It registered as a low-level 2.1 magnitude quake.
The property is owned by the Kennewick Hospital District, according to Benton County assessor records.
The Pacific Northwest Seismic Network is a cooperative effort by the University of Washington and the University of Oregon which monitors more than 300 seismograph stations across the region. That includes a separate contract to monitor the ground around Hanford.
Amy Wright, a seismic analyst with the network, believes the explosion came from the Hospital Quarry, which sits near Bofer Canyon Road. The rumbling from the area has become more common during the past year.
“There’s nothing to be alarmed about,” she said. “They’re a common thing.”
Benton County’s engineer did see some rock drills in the area, meaning they are likely blasting, said Shyanne Palmus, the county’s communications coordinator.
People in the desolate area likely didn’t feel the ground moving, she said. Generally, it takes at least a magnitude 3 quake before people notice it.
The surface-level explosions need to be larger before people notice them, because a portion of the energy is lost blasting the rocks loose.
The Benton County Sheriff’s Office could not be reached about the incident and Benton County Fire District 1 officials said they had not received any reports of an explosion or problem in that area.