2010 Mexicali quake still shakes California
The 7.2 earthquake that rattled the U.S.-Mexico border in 2010 — the largest temblor to hit Southern California in nearly two decades — has exposed a hidden weakness in school seismic safety that officials are now trying to correct.
The Easter Sunday temblor was centered south of Mexicali but was felt strongly in several Imperial County communities. Schools withstood the shaking structurally, but the damage was still extensive.
Walkway coverings cracked and collapsed; light fixtures crashed to the floor; electrical wires were exposed; water and gas lines ruptured; and classroom ceilings and roofs were damaged. On the athletic field of Calexico High School, the quake loosened and bent light poles, sparking fears that an aftershock could send them crashing onto athletes.
The damage underscores a loophole in the state’s earthquake regulations for schools. Strict laws mandate how buildings are built, but there are no regulations governing seismic safety inside them.
The state has launched a new campaign to get school districts to address the problem. Officials in recent weeks have been urging school districts to review a new checklist of potential safety hazards not covered by current codes.
They want educators to bolt down bookcases; secure potentially dangerous items like aquariums, photo copiers and televisions; better secure ceiling lighting; and repair cracked plaster over school walkways. The checklist also calls on schools to inspect electrical, gas and plumbing equipment to make sure it would survive a big quake.
The report can be found at lat.ms/schoolretrofit.
“It’s a fairly easy and inexpensive retrofit for existing facilities,” said Mike Gardner, chairman of the California Seismic Safety Commission. “So any school district, for not very much money, can go back and make their classrooms and offices far safer than they are today.”
The checklist is only a recommendation. It has been difficult to push legislation that would incur new costs.
Still, quake experts said they hope school districts will make the fixes a priority.
“Even though the building may stand up perfectly, the things in it can hurt people,” Gardner said. “We’ve learned over time that those are hazards in and of themselves.”
The Mexicali temblor struck in a remote section of Mexico and caused nearly $100 million in damage in California alone. But officials said the destruction at schools stood out.
Raul Martinez, the maintenance and operations supervisor for the Calexico Unified School District, said all of the district’s schools were closed for more than two weeks. One of them, Jefferson Elementary, is still closed as it undergoes a more extensive renovation.
Martinez said the biggest issue was the plaster soffits hanging above the school’s open-air walkways, which keep students dry during rainstorms. Many of the stucco overhangs, which extended about 10 feet from classrooms, collapsed. Before the temblor, quake drills had actually called for students and teachers to line up directly beneath the soffits, which in total weighed several tons.
“We’re so blessed that it happened on Easter Sunday,” Martinez said. “If we would have had students there, I can honestly tell you the chances were very good we would have had casualties, just with the force of the stucco coming down.”
Martinez agreed that more attention should be paid to non-structural items in schools. “I’m telling you honestly, all that stucco that came down, that could have killed somebody or hurt somebody really badly,” he said.
Los Angeles schools saw similar problems after the pre-dawn 1994 Northridge quake. But they were obscured by the greater destruction and death caused by the temblor. Educators said the school casualties from Northridge would have been significant had the temblor happened when classes were in session.
“We’ve been very lucky. But we need more than luck. We need something like this guide,” said Frank Kwan, a spokesman for the Los Angeles County Office of Education.
California’s quake regulations were inspired by the magnitude 6.3 Long Beach earthquake in 1933. The temblor destroyed 70 schools and damaged 50 others, about 75% of schools in the area, according to the California Department of Conservation. The quake didn’t happen during school hours.
In response, the state enacted the first in a series of strict seismic structure standards that cover how schools are built. But these codes do not cover some of the interior safety standards officials are now seeking.
Some newly built schools include interiors that are more earthquake-safe. The new Valley Region High School No. 5 in San Fernando, for example, has bolted cabinets as well as secure light fixtures with metal wires and reinforced ceilings, pipes and water heaters to prevent collapse. Music rooms are equipped with instrument cages.
As for older schools, earthquake experts said state regulators alone can’t do the job.
Fred Turner, structural engineer with the California Seismic Safety Commission, said teachers and even parents need to get together to make improvements.
“There are very significant limits to the role that regulators have in terms of ensuring occupant safety,” Turner said.
“I’d say the best model is PTAs getting together and working with janitors and [staff and] just doing it. There are a whole bunch of school districts and parents and teachers that have done just that. It’s remarkable what you can get.... Hold a party and bring the chips and dip, and believe me, I’ve seen it work.”
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