Alarmed residents made urgent calls to police to report loud blasts that turned out to be the booming of explosives used in an outdoor performance of Tchaikovsky's "1812 Overture."

"We received in excess of over 100 calls," Sgt. Mel Barnes said. "It's been unbelievable."

The calls started pouring in on phone lines including the emergency 911 line Saturday night after explosives were set off during a pops concert by the Glendale Symphony Orchestra, a community organization that was performing outside Glendale High School, Barnes said.

"It's a thrill for the youngsters," said Glendale Mayor Carl Raggio, who attended the concert, which he estimated attracted about 5,000 residents of the normally peaceful community.

It was the second year the symphony closed its annual outdoor summer concert with the dramatic "1812 Overture" and authorities had been forewarned about the explosions, Raggio said.

Rockets were fired into the air at appropriate times in the piece as concertgoers watched their trails light up the night sky and then burst overhead to mimic the noise of cannons, he said.

Barnes said police were inundated with a steady stream of calls between 9:45 p.m and about 10:20 p.m.

"I think it's been the best one we've had," Raggio said of the performance.