People have been talking about “The Big One” for many years, but the level of alarm over California’s vulnerability to earthquakes has never been as high as it is today.

Our state has more than a 99 percent chance of experiencing a magnitude 6.7 or larger earthquake within the next 30 years, according to the U.S. Geological Survey. The likelihood of magnitude 7.5 or higher is 46 percent.

These are staggering odds, considering that a 7.5 magnitude quake would deliver 45 times the force of the 1994 Northridge disaster.

Clearly, California is not prepared, and here’s we can do about it.

The closer you are to the convergence of two tectonic plates, the more likely you are to be impacted by seismic activity. California sits on a confluence of faults that crisscross the state like the fractures in a shattered mirror.

Every fault line puts us one step closer to disaster. In fact, buildings in the Greater Los Angeles area have up to a 5 percent chance of being damaged by an earthquake this year, according to the United States Geological Service.

That’s due in large part to the large number of buildings – as many as 300,000 structures standing today – that could crumble or collapse in an earthquake. These include:

  • Soft-story structures built before the mid- to late-1970s
  • Unreinforced masonry, mostly built before 1933
  • Concrete tilt-up built more than 40 years old
  • Non-ductile concrete built before the late ‘70s
  • Steel moment frame built before the mid-1990s
In Southern California, these numbers equate to one in every 16 buildings, the USGS assessment determined.

Devastating Social, Economic Impacts

Researchers at the University of Southern California determined that the economic impact of a projected 7.8-magnitude earthquake along the San Andreas Fault in Southern California would be the costliest disaster in U.S. history. Here are the numbers:

  • $113 billion in building damage
  • $68 billion in business interruption
  • $11 billion in related costs
  • Total Economic Impact: $192 billion

The U.S. Geological Survey and other agencies have confirmed USC’s numbers, estimating that a temblor of that size would kill 1,800 people, injure 50,000 and cause $200 billion in damage with long-lasting social and economic impacts. Those long-lasting residual impacts – as witnessed from past hurricanes, earthquakes, tornadoes and other natural disasters – test the resiliency of individuals, families, businesses, neighborhoods, lending institutions, local and state governments, and finally, the federal government.

And because California ranks as the sixth largest economy in the world, the ripple-effect of that impact could have wider domestic, even international effects.

What Can the Industry Do?

Left unchecked, the potential for this type of destruction would decimate communities, upend the lives and livelihood of thousands of families and send the economy into a downward spiral.

There is a high level of urgency in addressing this matter. This is clear with the growing number of newspaper articles addressing this concern.

As professional in the field we have not only the technical expertise, but the social responsibility to work toward a resolution of this looming threat.

Education plays a large part in getting members of the public to understand the threats they face. This is particularly true of building owners.

Stakeholders from industry, government and nonprofit organizations are joining forces to promote a statewide inventory of potentially vulnerable buildings that would help to further identify potential risks involved with major earthquakes in California.

The focus of the Seismic Resilience Initiative is to help cities identify buildings that could crumble or collapse under the massive ground force of a major quake and heightening public awareness of the urgency of this matter.

Preparing for “The Big One” also involves education among those in the industry, including best practices, technologies, applications and policy.

As one of the leading retrofit companies in California, Optimum Seismic has partnered with AIA in a series of articles designed to help inform members about trends, policy and proven techniques associated with earthquake retrofitting. This is the first in that series of monthly articles addressing these topics on behalf of AIA members. In the meantime, for more information on seismic retrofitting, please visit