Hundreds of people watched Warren Hall fall to the ground Saturday morning at Cal State East Bay's Hayward campus.
The old 13-story administration building was imploded at around 9 a.m. because it was the most seismically vulnerable building in the California State University system. Separately, scientists with the U.S. Geological Survey were also on hand for a quake study.
The Bay Area demolition was done with a bang, several actually - and took about 10 seconds followed by applause and cheers from the crowd.
A huge cloud of dust lingered on the campus for several minutes.
The implosion was proceeded by a warning horn 10 minutes before, 2 minutes before and one minute before the blast.
The building, which housed administrative officers and classrooms for four decades, was too tall to be taken down by crane, so the demotion team used 430 pounds of high explosives to blow up one side of the building. Gravity did the rest, experts said.
While most were interested in the explosion, scientists at the USGS were watching what happened underground after the building hit the ground.
Scientists seized the occasion to install nearly 600 seismic sensors within a 1.5-mile radius around the building to help them map fault lines and get a clearer look at the shaking caused by seismic events. The implosion was expected to create an effect similar to a 2.0-magnitude quake.
"We are trying to measure ground motion," Geophysicist Rufus Catchings said before the demolition. "When the building comes down there will be a thump that will put seismic energy into the ground."
The nearby Hayward fault was expected to amplify that energy.
Catchings said the sensors will help map where the fault is underground.
"Just because there is a ground break on the surface doesn't mean that is where the fault is underground. It's a zone, we want to see the width of the zone. We want to see how many strands are coming toward the surface," he said.
The information can then be applied all along the Hayward fault, from Milpitas to San Pablo Bay, and will tell scientists more about what will happen during an earthquake.
Rufus called it a rare opportunity.
"There is a tremendous number of things we need to learn about the fault zone if we understand that then we have a pretty good idea of what will happen in a much larger earthquake," he said.
Scientists said it would take several months to organize and analyze the data.
The building's occupants moved to a new Student Services Administration building on the east side of the campus and Warren Hall stood empty for about two years prior to this morning's demolition.
The CSUEB campus is set to reopen at 6 a.m. Monday.
Photo Credit: Josh Keppel