Sonic booms from military fighter jets rattle residents in Illinois and Oregon

Military aircraft creating sonic booms in separate incidents left communities in Illinois and Oregon rattled over the past week. Officials said shaking was felt by many residents, with some fearing an earthquake had struck.

On Tuesday, an F-15 fighter jet traveling over central Illinois created a sonic boom that rattled the region, prompting concerned residents to flood local police stations with calls about the noise, a state agency said. The Illinois Emergency Management Agency said in a statement that the department was alerted about 11:20 a.m. CST about "a large noise and shaking felt by many residents" across central Illinois.

The state agency said it began investigating with federal, state and local officials and found that the sound was a sonic boom from a military fighter jet.

"It was determined that an F-15 fighter jet in the airspace above central Illinois course corrected creating a sonic boom. When the aircraft broke the sound barrier, the pressure wave created an audible noise and minor shaking in the region," the state agency said in a statement.

There have been no reports of damage caused by the noise, it added.

The sonic boom in Illinois follows a similar incident in Oregon last week. Military officials said a sonic boom that caused widespread concern on the Oregon coast that an earthquake had happened was caused by an aircraft that "inadvertently went supersonic."

The 142nd Wing of the Oregon Air National Guard said the sonic boom last Tuesday was caused by aircraft.

Master Sergeant Steven Conklin, spokesman for the 142nd Wing, said the military is authorized to fly supersonic 15 miles beyond the coastline, but pilots should not have the nose of the jet pointed toward the coast.

The 142nd Wing in a Facebook post apologized for causing concern among coastal residents.

"During this training, we inadvertently went supersonic, and caused a sonic boom while pointed slightly toward the coastline while greater than 15 miles away from land," the 142nd Wing posted on Facebook. "We understand that this caused concern from our coastal residents and for that we sincerely apologize."

Conklin said the aircraft were a single-pilot F-15C and a two-person F-15D Eagle.

While speeds fluctuate during training, "it is not uncommon to go supersonic during basic fighter maneuvers, sometimes referred to as dogfighting," he said.