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Quake danger in Auburn? Placer County has its faults

By: Gus Thomson, Journal Staff Writer
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While Japan reacts to the horrific impact of an earthquake and tsunami, students in Dick Hilton’s earth sciences class at Sierra College’s Rocklin campus have been learning that a big temblor could strike just as quickly in the foothills. And Hilton teaches that when a quake with a magnitude of 6.5 shakes things up as geologists expect, the damage will take out much of the Gold Country’s stock of pre-1900 buildings. Hilton said Tuesday that the devastating quake could happen at any time and without warning. “It could happen in the next 10 minutes,” he said. That means Old Town Auburn, with a rich historic trove of 1860s-era architecture, would not survive the way Auburn-area visitors and locals know it today. “Old Town would be gone,” Hilton said Tuesday. “I tell my students that I wouldn't want to work in buildings that haven’t been earthquake-reinforced. It’s like having a gun with a hair-trigger pointed at your head five days a week, eight hours a day.” Placer County, like much of California, has its faults – fractures in the Earth’s crust that can release large amounts of energy as they move. The Foothills Fault Zone runs from about Oroville south to Fresno. The system runs through Auburn, Hilton said. Hilton said the damage to historic downtowns in Coalinga, Hollister and Watsonville after past temblors are good examples of what would happen to Auburn’s Old Town. “It would be devastating for Auburn because we have a lot of brick and stone,” he said. “We would lose our Gold Rush heritage.” The local faultline was the source of the 1975 Oroville earthquake, which had a magnitude of 5.7, and the lesser-known 1989 Emigrant Gap quake. Centered in eastern Placer County, the Emigrant Gap earthquake registered a 4.3 on the seismic scale. When the Japan quake hit, the seismograph at Sierra College registered the movement and one that came from an aftershock. Hilton said he provides some information about the Mother Lode fault zone but that students normally don’t pay rapt attention to the subject. But the lesson has been resonating since the Japan earthquake and tsunami occurred, he said. Chip Perley, working at Sun River Clothing on Tuesday, pointed to steel bracing lining the ceiling inside the 1850s building he was standing in. That was put in after the 1989 Loma Prieta earthquake increased safety standards, he said. But Perley notes that much of the brick that makes up Old Town’s oldest buildings, including the one he was in, is unfired and crumbles to the touch. “The only real advice in a building like this is, in all circumstances, run when an earthquake occurs,” Perley said. “These are sound buildings under normal circumstances but in an earthquake they’re no different than the ones in Grass Valley, Sutter Creek and other Gold Rush cities.” Dave Allen, an Auburn Parlor No. 59 member of the Native Sons of the Golden West, said the brick walls on the 151-year-old building the organization owns in Old Town are 18 inches thick. But Allen said it wouldn’t be safe in a quake. “It would crumble,” Allen said. “I would think many of the buildings would be in trouble but I’m not totally concerned. They’ve lasted this long.”