or three mornings a week I get up before dawn and go for a bike
ride. My route takes me up into the East Bay hills above my home
in Oakland, and it is unfailingly beautiful. Depending on the time
of year, I may see dawn lighting up the office towers of San Francisco,
fog lingering in the valleys of Contra Costa County, deer, wild
turkeys, or California quail on the hillsides, or red-tailed hawks
hovering over the ridgeline at sunrise.
My route also takes me over the Hayward Fault,
part of a nearly continuous system of earthquake faults running
from San Jose to Santa Rosa. Based on research since the 1989 Loma
Prieta earthquake, the U.S. Geological Survey concluded that there
is a 62 percent probability of at least one quake of magnitude
6.7 or greater, one that is sure to cause widespread damage, striking
the San Francisco Bay region before 2032. In other words, a major
quake is about twice as likely to happen as not to happen in the
next 27 years.
I like to think of the Hayward Fault as my own,
though I share it with millions of people. After all, my home is
less than half a mile from it. It runs straight through the University
of California, Berkeley, campus, Highway 13 is built along it, and
it bisects Highway 24—one of the busiest commute corridors
in the Bay Area—and the BART tunnel under the Bay. Over a million
people in the East Bay get their drinking water from an aqueduct
that runs through the Hayward Fault, and several critical high-voltage
transmission lines run through it as well.
As the Winter 2004–05 issue of Coast &
Ocean reminded us, life in California means living on the edge
of all kinds of natural disasters: earthquakes, floods, fires, and
landslides are all part of the state’s geology and climate.
Often these things occur in combinations: fire followed by landslide,
or earthquake followed by fire. In the wake of Hurricane Katrina
and the disaster in New Orleans, Californians have been reminded
again of one of our most catastrophic nightmares: an earthquake that
would destroy levees in the Sacramento–San Joaquin Delta.
On September 8, with much of New Orleans still under
water, the San Jose Mercury News reported that “Scientists
and state water experts have warned for more than two decades that
a large earthquake or flood could burst holes in the fragile 1,100-mile
network of levees crisscrossing the Delta from Antioch to Stockton.” Our
state capital, Sacramento, lies at the confluence of the state’s
two largest rivers. It is less than 20 feet above sea level and 90
miles from the ocean. Sacramento has a 100-year level of flood protection—the
lowest level of protection for any large urban area in the nation.
New Orleans had a 250-year level before Hurricane Katrina struck.
Failure of levees in the Delta and around Sacramento would not only
threaten the lives and destroy the property of the millions of people
who live there, it would also cut off much of the water supply to
urban southern California and to agriculture in the Central Valley.