Explosions in Rohnert Park late Saturday night launched more than 150 phone calls by concerned and angry residents to 911 for what turned out to be the long-planned fireworks show ending the gala debut of the Green Music Center at Sonoma State University.

The emergency calls came in a 20-minute period, about the length of the fireworks show, which started a little after 10 p.m.

Residents reported gunfire or a variety of other possibilities, Rohnert Park Sgt. Dave Welch said.

"There were a few surprised people and scared dogs," the sergeant said.

"A few callers were very, very angry, saying they were not notified," said Welch. "They were angry at the college, angry at the city."

Saturday night, the college celebrated the opening of the $145 million music center on campus with a concert attended by Gov. Jerry Brown and local luminaries and music fans.

The event and fireworks show had been publicized by the college and local media.

Three Rohnert Park dispatchers were on duty on the third floor of the city's public safety building and could see the fireworks from their window.

The deluge of calls inundated dispatchers, who quickly told callers the noise was from a fireworks show and moved on to the next call.

"They handled it as best they could," Welch said.

Cotati police dispatchers received two 911 calls about the fireworks, Cotati police said.

Sonoma County fire dispatchers said they didn't receive any calls.

You can reach Staff Writer Randi Rossmann at 521-5412 or randi.rossmann@pressdemocrat.com.