© WTMZ
People in areas like Quakertown and Coopersburg say they're being woken up by loud booms and some even say the blasts shake their homes.
"It is quite loud," says Donna Weaver of Quakertown.
Weaver is one of many who hear loud booms in the middle of the night.
"It went boom, boom, that's what it sounds like to me and that sounds like an explosion," said Weaver.
Residents said the booms consistently sound off around 2:00 a.m. and there are typically two rounds, five minutes apart.
"It's just a boom, it almost sounds like we would live right next to a quarry," said Quakertown resident Cindy Warden.
Neighbors are calling it a mystery and so are police.
The Richland Township Police Department say it's received a lot of calls about the explosions.
The department posted a message on Facebook that says in part, "Rest assured, we are not aware of anyone having permission to blast, and hope to help in locating the source of these explosions. If anyone sees anything suspicious in that area, please reach out to Police or the township."
"Nobody can figure out what it is," said Weaver.
As Richland and Milford Township authorities work to investigate the issue, the theories behind the booms are swirling on social media.
"Some people were saying maybe they think it's kids throwing M-80's or cherry bombs, others are saying aliens," said Weaver.
People in Springfield Township also say they hear the booms.
Comment: Update: According to ABC6, the mysterious explosions are continuing in Bucks and Lehigh counties. Some residents report the booms sound like vehicles slamming together, others report the noise reminds them of fireworks or underground blasting. The Richland Township chief of police is quoted as saying two of his officers heard the sound, one first seeing a flash: The State Police are investigating and have asked the ATF and FBI to assist in the investigation.