September 7, 2005

Natural risks find new scrutiny in Katrina’s wake

By Kevin Krolicki

LOS ANGELES (Reuters) - Pick your cataclysm: A tsunami
washes over Miami. A massive quake rips Los Angeles. Or the
volcano under Yellowstone erupts, spewing ash across America
and ushering in a new Ice Age.

Surprised by Hurricane Katrina's destruction of New Orleans
and the problem-plagued recovery, experts are revisiting with a
new concern the risks posed by everything from killer asteroids
to ocean-shaking landslides.

They also are considering a haunting new question: How can
a disaster as widely predicted and slow-moving as a storm still
pack such a devastating surprise in the United States?

"Hurricanes happen with some regularity and we can't deal
with them. How can we deal with an earthquake?" said Nassim
Nicholas Taleb, a specialist in uncertainty and risk at the
University of Massachusetts. "We have a problem."

The potential catalog of calamities considered by
scientists starts with the near-certainty of a major earthquake
on California's San Andreas fault, and proceeds to far-shot
catastrophes such as an Atlantic Ocean tsunami triggered by a
volcanic landslide.

Then there are the "near-earth objects" and
"supervolcanoes" -- seen as tiny risks now despite a geologic
record of life-altering catastrophe.

NASA's Jet Propulsion Laboratory, which tracks asteroids at
risk of hitting Earth lists three for "careful monitoring."

Those include a mass 350 yards in diameter given a
1-in-5,560 chance of crashing here in April 2036, the nearest
collision window of the asteroids most closely watched.

Steve Chesley, a NASA astronomer, said none of the 1,200 or
so near asteroids that are larger than 1,100 yards are on the
watch list -- good news since it is believed it would take an
object of that size to deliver a climate-changing blow to the

Many scientists believe that an impact near Mexico's
Yucatan peninsula led to the extinction of the dinosaurs, by
ejecting dust and particles into the atmosphere which chilled
the planet for several years.

Even so, Chesley said, a medium-sized asteroid of the kind
that top NASA's watch list would be "absolutely capable of
causing damage across several states, for example."


Asia's deadly tsunami in December focused attention on the
risk from the huge waves triggered by earthquakes and other
events of equal power.

Steven Ward, a geophysicist at the University of
California, Santa Cruz, has studied the threat of a tsunami if
the Cumbre Vieja volcano erupted in the Canary Islands.

Such an outburst, he projects, could cause a steep block of
the island of La Palma to break off and crash to the ocean
floor, touching off a rare Atlantic tsunami.

The worst-case rupture could send waves of up to 300 feet

to the African coast within an hour and 75 feet

tall to the beaches of Florida after nine hours. "These
things do happen," Ward said.

Then there is the scenario in which a little-recognized
volcano under Yellowstone National Park in Wyoming erupts
again. The volcano spit out enough debris in a massive burst
2.1 million years ago to bury Texas with 12 feet of ash.

The risk of any eruption in the next hundreds of years is
seen as very small, but the prospect of a killer blast drew
attention after a 2003 BBC "docudrama" on the subject.

"My dad always used to joke that more people probably die
of tripping on their shoelaces than from volcanoes," said
Smithsonian Institution volcano expert Rick Wunderman. "But
we'd like to look ahead and know what's coming -- just like
with this hurricane."

The closest thing to a sure-bet U.S. disaster awaits in
California, experts agree.

A magnitude 7.5 quake under Los Angeles could kill as many
as 18,000 and cost $250 billion, according to computer models.

Meanwhile, the state's San Andreas fault is seen certain to
at some point set off a magnitude 8 quake, possibly more
powerful than the quake that destroyed San Francisco in 1906.

That would cut off the water and natural gas flows into Los
Angeles, sever road and rail ties and effectively strand a
region with 10 times the population of New Orleans, said Lucy
Jones, a scientist with the U.S. Geological Survey.

"It is absolutely when and not if," she said, urging
residents to take steps now to recognize the risk and prepare.
"I'll bet most people in L.A. don't have a store of water."