A Taste of the Big One - From TerraDailyNews

by Tangi Quemener
Los Angeles (AFP) May 26, 2005
As Californians brace nervously for the "big one," scientists Wednesday
offered a computer-generated glimpse at the death and destruction a major
earthquake could wreak in the second largest US city.
A major temblor triggered by just one recently-discovered fault cutting
through downtown Los Angeles could devastate the city, killing up to 18,000
people and causing as much as 252 billion dollars in damage, they said.

Geologists, who discovered the Puente Hills fault in 1999, warned that a
potential quake in such a built-up and industrialised area could be
catastrophic, especially if it occurred during the busy daytime period.

"The dollar losses would be between 82 billion dollars and 252 billion
dollars and the number of fatalities would be between 3,000 and 18,000," US
Geological Survey geophysicist, Ned Field, told journalists.

Seismologists say the active fault lying three kilometers (two miles) below
Los Angeles has ruptured at least four times in the last 11,000 years,
triggering temblors with magnitudes between 7.2 and 7.5 on the Richter
Scale.

Such a quake in the heart of the city that is home to around nine million
people could also leave 60,000 to 260,000 people injured, according to Tom
Jordan, director of the Southern California Earthquake Center.

Between 142,000 and 735,000 people could be displaced if such a temblor
were to strike from the Puente Hills fault, far outpacing the devastation
of the last major quake in Los Angeles 11 years ago, the experts said.

The potential for enormous damage is "very high" as such quakes are "very
dangerous when they occur," said Jordan of the findings of the study he
co-authored that is published in the May issue of Earthquake Spectra.

The scientists created 18 computer-generated scenarios depicting different
shaking patterns through the populous region in a bid to determine possible
losses of a big quake generated by the fault.

The experts warned a collision of plates in the Puente Hills fault could
produce far more damage than earlier quakes here as it lies under old and
more vulnerable commercial and industrial structures of the city.

But the experts stressed that the chances of such a huge and devastating
quake generated by the recently-discovered fault remained relatively low.

A full fault rupture of the fault is rare, occurring once every 3,000
years, Field said, saying that residents of the Los Angeles had a much
greater chance of dying in a car accident than an earthquake.

However, Field warned, "something's got to give" - sometime. And Puente
Hills is only one of a welter of fault lines criss-crossing Calfornia, the
richest and most populous US state that boasts the world's fifth biggest
economy.

Residents of the state have for years been waiting for the massively
destructive "big one," long predicted to be lying in wait in the notorious
San Andreas fault.

Seismologists estimate that there is a 70 percent chance of a major quake
along the famed fault within the next 30 years.

And the scientists Wednesday issued a salutary warning to residents of the
sun-drenched state that Hollywood has made into the stuff of dreams for
most of the world: "Unless you die very soon, you will be the victim of a
destructive earthquake."

A massive magnitude-6.7 earthquake hit in Los Angeles' largely residential
San Fernando Valley area in the early hours of the one morning in 1994,
killing 37 people and causing around 40 billion dollars in damage.

USGS expert Lucile Jones said that one third of the loss of life in a major
quake was "the result of non structural damage" - when furnishings and
other items inside homes and offices fall on victims, rather than the
buildings themselves.

Residents and planners in the perilous region that however attracts tens of
thousands of hopeful new residents each year could limit the risk of death
and damage caused by quakes, Jones said.

"We can reduce hazards through societal choices that we make," she said
including following safe building practices and ensuring that all new
structures and built to the state's tough code for earthquake resistance.