GRAND RAPIDS, Mich. (WOOD) — A loud sound from an unknown source has prompted concern in Grandville and the surrounding area prompting numerous calls to 911.

Kent County dispatchers say they’ve received nearly two dozen calls reporting a loud explosion-type sound. Police have been searching the area, but were unable to determine the source of the noise.

Reports of the situation began coming into the 24 Hour News 8 newsroom around 8:30 p.m Saturday.

“There was just a loud explosion sound in Grandville and we felt the earth shake,” one viewer wrote on Facebook.

“Sounded like a bomb going off!!” said another post.

Emergency responders remain perplexed as to what caused the sound.

Anyone with information is asked to call the Kent County Sheriff’s Department at 616.632.6100 or Silent Observer at 616.774.2345.