California Earthquake Drought & Seismic Retrofits

A whole generation of Californians have now grown up without experiencing a damaging earthquake, and some people worry that we’ve become complacent about seismic safety here. But that’s not what I see. In fact, many of these steps are being taken. Since 2012, eight California cities have passed mandatory retrofit ordinances and many more are considering it. The question is how fast and aggressively the work gets done.

The earthquake drought is giving us a chance to make better decisions and reduce our losses. Will we take it?

Lucy Jones was a seismologist with the U.S. Geological Survey for 33 years and founded the Dr. Lucy Jones Center for Science and Society focused on creating resilient communities in 2016. She continues to work at Caltech and is the author of the book “The Big Ones.”

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Source:  LA Times

Los Angeles Seismic Retrofit Compliance

A Los Angeles City Council committee that was briefed Tuesday on seismic upgrades required by law in roughly 15,000 buildings was told that 14 percent of soft-story wooden structures are now compliant but none of the affected concrete buildings have been retrofitted.

When Mayor Eric Garcetti signed the 2015 ordinance into law, it gave Los Angeles the nation’s strongest earthquake safety rules. The measure applies to older buildings considered vulnerable in major earthquakes, including wood-framed “soft-story” buildings with weak lower floors, such as multi-story apartments with tuck-under parking spaces, and vulnerable concrete buildings.

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Source: MyNewsLA.com

Pasadena Seismic Retrofits

Owners of hundreds of multifamily residential buildings in Pasadena would need to pony up the cash to pay for seismic retrofits under a plan advanced by the City Council on Monday.

The council directed the city attorney to draft an ordinance to require certain older buildings be shored up to protect against earthquakes. The structures impacted are known as “soft-story” buildings — which can include apartments with parking spaces underneath and those built prior to 1978.

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Source:  Pasadena Star-News

The Northridge earthquake that hit 25 years ago offered alarming evidence of how vulnerable many types of buildings are to collapse from major shaking.

It toppled hundreds of apartments, smashed brittle concrete structures and tore apart brick buildings.

Since then, some California cities have taken significant steps to make those buildings safer by requiring costly retrofitting aimed at protecting those inside and preserving the housing supply.

But many others have ignored the seismic threat. And that has created an uneven landscape that in the coming years will leave some cities significantly better prepared to withstand a big quake than others.

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Source:  Achorage Daily News

2017 Mexico City Earthquake

Seismic safety experts long have warned that brittle concrete frame buildings pose a particularly deadly risk during a major earthquake.

But a horrifying video taken during this week’s magnitude 7.1 Mexico quake may do more to highlight the risk than years of reports and studies.

In it, sirens blare, utility poles sway. Then in the background, a building wobbles. Concrete starts falling out of a ground-floor column. Then the columns flex, and the upper floors come crashing down, sinking into a cloud of dust.

“¡Dios mío! ¡Dios mío!” a woman is heard saying. “My God! My God!”

The crumbled Enrique Rebsamen school in Mexico City — a three-story structure where at least 25 died, including 21 students — was made of concrete, as were many other structures that fell to the ground.

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Source: LA Times

After a massive earthquake struck central Mexico, horrifying images of collapsed buildings emerged and had many Los Angeles residents wondering if that could happen here. One expert said yes.

“This is a vivid reminder – these videos we’re seeing – that this could happen here,” said Dr. Ken Hudnut, with the U.S. Geological Survey.

A recent study said 15,000 structures in the city have been identified as vulnerable for collapse during an earthquake. The bulk of the buildings are called “soft story structures.”

 

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Source:  KABC 7 (abc7.com)

Santa Monica Seismic Retrofit Video

On August 25th, 2017, the City of Santa Monica published a short informational video on their YouTube channel describing the city’s new Seismic Retrofit Program and the steps needed for business owners and tenants to comply.  Watch the video below:

The U.S. Geological Survey is moving its earthquake early warning system into production with a $4.9 million in awards to research partners and $1 million in new sensor equipment.

The system, called ShakeAlert, uses ground-based sensors to identify and characterize an earthquake within seconds after it begins, and deliver warnings to people and infrastructure in harm’s way. It detects an earthquake’s initial P-wave energy, which rarely causes damage, to estimate the location and the magnitude of the earthquake. It then sends a warning to local populations before the arrival of the S-wave — the strong shakes that cause most of the damage.

Source: GCN.com
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New LA Earthquake Maps

The 1971 San Fernando (Sylmar) earthquake killed 64 people, buckled roadways and leveled scores of buildings. Soon after, California passed a law that requires updated mapping of major earthquake fault zones.

But due to a lack of funding, the effort ground to a halt not long after it began and resumed only about four years ago.

The California Geological Survey’s newly released mapping of the Santa Monica Fault could, if approved after a 90-day public comment period, prohibit new construction on top of active sections of the fault and require extensive geological review for proposed development within 500 feet.

“The Santa Monica and Hollywood faults historically have been fairly quiet since the area’s been settled, as far as we know,” says California Geological Survey senior engineer Timothy Dawson. “The major concern is that these faults cover some of the most densely populated areas in the L.A. basin.”

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Source: KQED News

 

Mayor Garcetti Addresses Seismic Fault Data

Drive about 100 miles east-northeast of San Diego and you’ll come to the Salton Sea, a quasi-oasis whose surface is so glassy it reflects the sky in exquisite detail.

Don’t be fooled by the serenity. You’re looking at a potential killer.

Beneath the seafloor lie strands of the southern San Andreas fault, a 340-mile system that could rupture all the way to Monterey County.

The result would be the “Big One,” an earthquake that experts said would collapse buildings, destroy freeways, warp rail lines and crack dams. Thousands of people could die.

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Source:  San Diego Union Tribune