Story and photos by Issac Jeitler
GROSSMONT COLLEGE – To simulate the sounds of an earthquake on Thursday, Oct. 20, Professor Jim Papageorge set up six sets of speakers in the Main Quad ranging from 28″ subwoofer drivers to 15″ loud speakers.
The system, which Papageorge estimated generated 30,000 watts of power, was used to, “move a great deal of air to produce the simulated earthquake.” Sound effects were played through an instant replay machine which triggered the sound effects to pulse up to 50 cycles per wave through the system.
A mixture of “earthquake and thunderstorm sound effects” were then used to create a low rumbling infused with bone- jolting crashes which resembled an earthquake.At the epicenter of the 50-square-foot speaker pyramid, anywhere from 115 to 130 dB (decibels = audio wave power and intensity) could be felt, equivalent to what would be generated by a 7.5 earthquake on the Richter scale.
However, no participant was subjected to these dangerous conditions. Set back 50 feet, they may have experienced an ear- and body-numbing 90-100 dB.The quad was abuzz with students during the evacuation drill and not just the buzzing in their ears. Papageorge is an avid audio enthusiast and when he does a production, he goes big.
“If this test took place in a small room, it would make the room reverberate.” Needless to say, the simulated version in the quad was huge and the campus helped in its part to participate in the largest statewide earthquake drill to date.
*
Jeitler is features editor of the GC Summit. He may be contacted at [email protected]
