Translated from Latin, Isaac Newton’s first law of motion defines inertia as, “every body persists in its state of being at rest or of moving uniformly straight forward, except insofar as it is compelled to change its state by force impressed.”

In our work?  It’s the tendency of people to keep doing the same thing they’re already doing, or to do nothing at all.

On January 16 and 17, I was pondering the two meanings of inertia as my colleagues and I joined some of the world’s elite earthquake organizations to present a symposium entitled, Northridge20.

The symposium marked twenty years since the 6.7M Northridge earthquake struck Southern California in 1994.  More than 600 academics, code specialists, consumers, elected officials, emergency managers, engineers, geophysicists, insurers, product manufacturers, researchers, risk communicators, seismologists and social psychologists attended.

For two days, we recalled the devastation, heard stories of heroism and celebrated advances in earthquake detection, engineering and policy.  The experience reinforced the common theme between the earthquake community and the different expert groups in disaster safety — a passionate commitment to progress and simultaneous fear of running out of time before the next “big” event occurs.

The concern is justified.

As we were heading to Los Angeles for the Symposium, UC Berkeley researchers released a hotly-debated list of 1,500 concrete structures in and around the city that were built before 1976 using less reinforcing steel than is now required.  Eight years ago, UC Berkeley engineering professor Jack Moehle set out to produce the list of older structures because he believed that “existing vulnerable buildings are the No. 1 seismic safety problem in the world.”

According to the Los Angeles Times, “Despite their sturdy appearance, many older concrete buildings are vulnerable to the sideways movement of a major earthquake because they don’t have adequate steel reinforcing bars to hold columns in place.”  Based on past events, the researchers suggest that five percent (or 75 of the 1,500 buildings) on the list may collapse in an earthquake.

It is important to note that 95 percent of the structures are expected to perform ably and advancements in concrete construction practices make structures built since that time reliably resilient.  Remember that some of the world’s most enduring buildings and monuments are made from concrete.  The 2,000-year-old old Roman Pantheon springs to mind.

So the challenge with the list is that it does not identify the 75 potentially unsafe buildings that could collapse or “pancake” in an earthquake, as that can only be done through a physical inspection.  The cost to inspect ranges from $4,000 to $20,000 per building, and some suggest that structural retrofits could cost as much as $1,000,000.

Who will pay for the inspections?  What about the retrofits?  Where will people live and work while the retrofits are undertaken?  How will this affect real estate values and the overall economy?  These questions make it easy to see how complex an issue this is for leaders.

But the public is now aware.  During the panel I moderated at the Symposium, we heard from a law professor in the audience who said she recently moved from her apartment in one of the older buildings into a converted garage because she was overwhelmed by constant fear.  I imagine she is not the only resident of Southern California who is living in a state of unease.

Identifying and fixing unsafe concrete buildings will take time and will be costly.  This is just one stark example of problems with outdated building practices in disaster zones.  But one thing is clear.  Momentum is taking hold, and the inertia defined as in a “state of being at rest” is slowly giving way to inertia that is “moving uniformly straight forward” to achieve resilience in the face of earthquakes.  “Force impressed?”  It’s the disaster safety movement of course.