People often reference the Northridge earthquake of 1994 when they speak about seismic disasters. After all, it’s something many of us experienced first-hand: an event that we can relate to.
The 6.7-magnitude thrust of the quake rattled Southern California a mere 10 to 20 seconds and caused $67 billion in widespread damage.
Yet the magnitude of that quake was relatively mild compared to what could be.
Seismologists say the next “Big One” – which could come at any moment – could be of a magnitude of 7.5 or more, ripping along the fault and displacing it by an average of 9 feet.
Know the risks and be prepared
The U.S. Geological Survey and other agencies estimate that a temblor of that size would kill more than 1,800 people, injure 50,000 and cause $200 billion in damage with long-lasting social and economic impacts. Those residual impacts – as witnessed from past hurricanes, earthquakes, tornadoes and other natural disasters around the nation – test the resiliency of individuals, families, businesses, neighborhoods, lending institutions, and local, state, even federal governments.
A lot has been learned from earthquake models since the Northridge quake. We now understand much more about seismicity, ground motion and engineering, and these advances in technology have allowed us to identify threats based not only on geography – i.e., proximity to fault lines and soil composition – but also by building characteristics.
Seismic retrofitting of these vulnerable structures is critical to reducing risk, the Federal Emergency Management Agency study found, along with a growing number of cities now requiring retrofits of these structures.
Cost Benefits to Building Owners
Researchers at Caltech recently determined that for every dollar spent in retrofitting soft-story structures, property owners could expect to save up to seven dollars, and that study didn’t factor in loss to contents, alternate living expenses or deaths and injuries – all of which would have significantly increased the cost-to-benefit ratios.
FEMA found similar cost benefits in a two-year analysis of seismic retrofit scenarios applied to a variety of building types in locations throughout the United States. The study found high benefit-to-cost ratios for California, including a scenario of a tilt-up warehouse building in Hayward. “In this example,” the study found, “the benefit/cost ratio is about 10 without the value of life and about 12 with the value of life. The benefit/cost analysis suggests that retrofit is strongly justified economically, even without including the value of life.” That return on investment was even higher for tilt-ups with a higher occupancy, such as light industry, the study found.
Researchers at Caltech determined that seismic retrofits are cost-effective when expected annualized loss would be reduced by 50 percent or more at a cost that would equal no more than 10 percent of the replacement cost of a building.
Apart from the structural losses associated with earthquake damage, these other factors are important points to consider when weighing the cost benefits of a seismic retrofit:
- Liability associated with damage, death and injury
- Loss of income when a building gets red-tagged
- Financial obligations tied to the original mortgage loan
- Demolition costs including abatement of asbestos and lead
- Reconstruction costs and cost overruns
Educate yourself about your building risks
A scene in the movie “L.A. Story” shows Steve Martin dining with friends when a massive earthquake starts shaking wildly. Glasses rattle, tables scoot across the floor. An ice sculpture swan takes a nose dive into a platter of fruit. Yet everyone continues their conversation unfazed – as if nothing is happening. It’s all business as usual.
Clearly, Californians live in earthquake denial. We laugh it off, ignore its ever-present threat to our lives and our livelihood. But this is an issue that should be in the forefront of everyone’s minds. Are we prepared at home, in our place of business, in our hospitals, schools and community? How quickly could we recover from that looming 7.5-magnitude earthquake, and how severely would economic disaster in California ripple throughout the rest of the nation?
Retrofitting your building to protect against damages in a quake not only helps to guard against death, injury or damage – and the potential for subsequent liability or loss of income – it helps to safeguard the value of your investment.
How many of us insist that our children wear seatbelts while driving? Why wouldn’t we want the same safety precautions for our buildings?