Mystery surrounds shaking felt Tuesday night from at least Weber County to Salt Lake City, accompanied by a rumbling noise.
Dispatchers received several calls about 9 p.m. from people who felt the rumble, but an explanation for it remained elusive. There was no earthquake in Utah on Tuesday night, said Jim Pechmann, a seismologist at University of Utah Seismograph Stations, but research instruments did pick up two sonic waves about 9 p.m.
A plane breaking the sound barrier could cause such a wave, as could an explosion though quarries cannot legally blast at night, Pechmann said. Wherever it originated, the inversion can cause a sonic wave to travel farther than it normally would, he added.