The instruments deployed to study those swarms form the most
OGS seismologist Austin Holland, who was already studying the recent seismic activity in Oklahoma, was in the field Monday gathering data about Saturday's quakes.
Many people in the region who felt the quake reported hearing a noise,
Oklahoma and much of the eastern U.S. sit atop hard bedrock that transmits shock waves across a much wider distance than some quakes west of the Rocky Mountains, according to the USGS. Similar earthquakes happen occasionally at unpredictable times and places across
Keller has likened it to a metal pole struck by a hammer.
The waves move through the Earth's crust in a way that creates a low-frequency sound. People have described it like thunder, a sonic boom or a vehicle crashing into their house.
People as far away as Dallas and St. Louis reported feeling Saturday night's earthquake.
Drills likely unrelated
Keller said the chance is remote that oil and gas drilling activities in the area had anything to do with the earthquakes Saturday. The quakes were centered more than two miles below the ground, far below drilling in the area.
“It's way below any depth anybody is pumping or injecting or anything else, and it isn't a particularly active area, oil and gas-wise,” Keller said.
Residents in nearby states have blamed hydraulic fracturing and gas injection wells for small earthquakes, and the Arkansas Oil and Gas Commission shut down some injection wells in an area where there were concerns that earthquakes were linked to oil and gas
Holland has studied the swarm of smaller quakes in Oklahoma for links to the oil and gas industry, but has said he found little evidence they're related.