Canisius scientist explains earthquake "boom:

A local scientist has offered an explanation.

What residents heard -- and didn't feel -- is quite common for an earthquake this size, says Mark Castner, director of the Braun-Ruddick Seismograph Station at Canisius College.

In explaining, Castner says the highest frequency seismic waves are typically just a little below human hearing, which means people sense them more as a "boom" more so than actually hearing a noise.

"It's not uncommon for people to hear a boom or a rumble from an earthquake, but then there are lots of earthquakes where nobody hears any noise of that type," Castner says.

Castner says Western New York has a small magnitude earthquake about once every two years, but they're not evenly distributed.