Foon Rhee

The Numbers Crunch: Waiting, worrying and preparing for the ‘Big One’

College students Kaitlin Pearn, left, and Rebecca Langenwalter act during California’s annual earthquake drill in 2014. Organizers say more than 10 million Californians signed up for the “Great ShakeOut.”
College students Kaitlin Pearn, left, and Rebecca Langenwalter act during California’s annual earthquake drill in 2014. Organizers say more than 10 million Californians signed up for the “Great ShakeOut.” Associated Press

Somehow, in all my time in California, I’ve never felt an earthquake. But I did in North Carolina, of all places.

The closest I came was the Napa quake a year ago this coming Monday – at 6.0 magnitude the strongest in Northern California since the deadly Bay Area quake in 1989. While more than 1 million felt the shaking, I slept right through it. I do, however, remember being jolted awake when a 3.2-magnitude quake hit near my home in Davidson, N.C., in 1998.

According to a new report, I guess I shouldn’t be that surprised. After updating its risk assessments, the U.S. Geological Survey found that quake danger is far more widespread across the country than previously believed.

More than 143 million people in the contiguous 48 states live in areas that are exposed to potentially damaging quakes, nearly double the 75 million in 39 states in its 2006 study. When Alaska, Hawaii and U.S. territories are added, the number rises to nearly half of all Americans. The higher estimates come from population growth and from scientific advances that better measure earthquake hazards.

One fact didn’t change in the new assessment: Californians are still at the greatest risk of very strong earthquakes. Of the 44 million Americans who live in those areas, nearly 31 million are in California.

The next state on the very strong shaking list is Washington with 4.9 million. The numbers go way down from there; 31 states don’t have any residents at risk of a very strong quake at all. (Earthquake risk is calculated based on a 2 percent chance of one happening in 50 years, the typical life span of a building.)

This past Monday, we were nudged by a small reminder that California is earthquake central – a 4.0-magnitude quake on the Hayward Fault near Berkeley that was felt in downtown San Francisco and the East Bay.

Given that California is at the epicenter of risk, it’s a good thing that an early warning system is finally getting off the ground.

Two years ago, the Legislature passed and Gov. Jerry Brown signed a bill that calls for a statewide network of sensors. They’re designed to detect the first shock waves and give a warning of as much as a minute before the more destructive waves hit – precious seconds for people to seek shelter, for mass transit systems to stop and utilities to power down.

The ShakeAlert system’s price tag is estimated at $80 million for development and $20 million annually for operations. But supporters point out that the cost is tiny compared to the potential savings in medical costs and infrastructure damage in a major quake. They also note that the U.S. is well behind Japan and other countries in using this technology.

Senate Bill 135 called for a public-private partnership to pay for the system, and set a Jan. 1, 2016, deadline for funding to be identified. In December, Congress allocated $5 million to start rolling out the system on the West Coast.

The USGS spent $1 million on 150 new and upgraded sensors. Last month, it announced that the other $4 million is going to UC Berkeley, Caltech, the University of Oregon and the University of Washington to move ShakeAlert toward the production stage. With the existing system, some East Bay residents received a warning 20 seconds before Monday’s quake.

The threat of the “Big One” is just part of living in California. If and when it happens, all bets are off. Still, it’d be nice to get that few extra seconds to try to survive.

By the numbers

The 10 mainland states with the most residents at risk for a very strong earthquake:

  • California, 30.6 million
  • Washington, 4.9 million
  • Utah, 2.3 million
  • Tennessee, 2.0 million
  • Oregon, 1.4 million
  • South Carolina, 758,000
  • Nevada, 619,000
  • Arkansas, 374,000
  • Missouri, 321,000
  • Illinois, 215,500

Source: U.S. Geological Survey