National Geographic: Born of Fire Page #4

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in Los Angeles

Twisting railroad tracks

shattering highway overpasses

it strewed disaster across

the city landscape

as if by an angry giant's hand

Like a silent accomplice

flames leaped through the wreckage

Great hospitals and other

structures collapsed

Everywhere the quake trapped

its casual human victims

When it had passed, the city counted

the cost 64 dead

in property damage

Because the water behind a weakened

dam was quickly lowered

thousands of lives were saved

which otherwise might

have been lost

In it's aftermath alarmed public

agencies radically

expanded their earthquake

preparations

Today not only standard

surveying methods

but a wide array of new

instruments are employed

to monitor California's

fractured landscape

Using laser beams and radio waves

from remote stars

scientists can measure the state

for crustal changes

or plate movements as small

as an inch

Along the San Andreas a network

of seismic devices

reports local changes in the release

of radioactive gas from rock strata

sudden drops in the water level

of wells

variations in gravity or the

Earth's magnetic field

Other meters detect the slightest

movement deep beneath the surface

measure strain in a locked section

of the fault

the state of California also

is checking its basement"

above which 24 million

people live

From hundreds of

instruments scattered

across the length of the state

continuous reports flow into

separate computer centers

for the southern and the

northern sectors

At the United States Geological

Survey in Menlo park

widely diverse in formation

is correlated

and condensed to provide a summary

of seismic activity

during each passing month

Like scholars trying to break

an enemy code

or decipher a lost language

scientists are trying to discern

a consistent meaning

in all the signals sent

from the Earth

Though the San Andreas remains

an enigma

a silent threat of havoc to come

sophisticated technology is

bringing closer the time

when man may be able to

predict earthquakes

with reasonable accuracy

and certainty

Scientists know

that in prediction lies a major

defense against catastrophe

Using an instrument no more

complicated than a garden hoe

one young geologist

from the California Institute of

Technology has shown

that the key to the future may lie

in the past

At excavations along the fault at

Pallett Creek near the Mojave

Dr. Kerry Sieh has revealed

a repeat pattern

of California quakes hundreds

of years

before any recorded history

of the region

"We are on the main trace of the

San Andreas Fault

And the layer that I just scraped

off

has been radiocarbon dated

at 1350 A.D.

The layer right

above it

which has the beautiful orange

color here

and here has a radiocarbon date near

its top of about 1560 A. D

or about the time Michelangelo was

painting the Sistine Chapel

This layer dates from about the birth

of Benjamin Franklin 1700

and this layer about right here

was the surface of the Earth

at the time of the 1857 earthquake

"Now, this is the main trace of

the San Andreas Fault running up

through these layers up though to

about here."

"Here's the 1353 A.D. layer broken

by the fault trace coming up

through the 1560 A.D. layer here

So here we have the Pacific Plate

and here we have the

North American Plate

broken only by this very narrow trace,

or plane

of the San Andreas Fault."

"And it continues on up

up through the 1700s level

and stopping at this level

the 1857 level

In 1857 there occurred the great

Fort Tejon earthquake

which was the last great earthquake

to break the San Andreas Fault

in the southern part of the state."

"Elsewhere at this site

we have exposures a total of 11

prehistoric earthquakes

and the great Fort Tejon earthquake

of 1857

The radiocarbon dates show

that the earthquakes occur

with frequency

they occur about every 145 years

It's been 125 years since the great

Fort Tejon earthquake

The chances are really quite

good that

within our lifetime

we're going to see another great

Fort Tejon earthquake."

"Give me the number of dead you

anticipate

that you are estimating

and I will try to work it out on

the end."

"Estimates of injured range

from 50 to 80 thousand

with an unknown number trapped in

collapsed structures

At this time the numbers of dead may

be in excess of ten thousand."

To train disaster agencies

and to alert the public the state's

Office of

Emergency Services stages

yearly drills

"I would like to clarify what's

turned out to be a rumor

of a radioactive release problem

at Cal Tech."

Alex Cunninham

director of the California Office

of Emergency Services

"The scenario for this exercise is

that an earthquake occurred

yesterday in Los Angeles

actually about 30 miles northwest

of San Bernardino

along the San Andreas Fault

Its magnitude, for exercise

purposed 8.3."

"And believe me

we are very selective

at this level on

using Guard resources

And I recommend strongly now

I can't handle a delicate issue

like this on the phone

I recommend very strongly that if

you want the Guard for this

that you are going to have to come

through bureaucratic channels."

"We need to have an update

as of this time on the number of

injuries and deaths, please."

"All the hospital beds in northern

county appear be down

Southern county looks like

they're in pretty good shape

But the Needs Assessment will be

back half an hour and will give us

all the figures."

"Hold on a second. We got to

get this together."

"The State of California is

very well prepared to

handle a moderate earthquake

And the citizens who have been

through these kind of quakes

are reasonably well prepared

But when we talk about a

catastrophic earthquake

something in the area of an 8

or an 8.3 no level of government

and particularly the

individual citizens

are prepared for such an event

It's no longer a question of if

the big earthquake is coming

It's simply a matter of when

Scientists are telling us

because of recent seismic activity

and other phenomena

other scientific data

that the great earthquake will strike

in southern California

some time in the next 30 years

Unfortunately, many people say well

if it's 30 years away

we don't have to worry about it

It's not 30 years away

It could happen tomorrow

it could happen today;

it could happen next month

But sometime in the next 30 years

we're going to have it

and people damn well better

prepare themselves for it."

Distantly aware of

threatened holocausts

most Los Angeles residents remain

caught in the traumas

and traffic jams of daily life

Too few know the mathematics of terror

At the time of the 1857 quake 11,000

people lived in Los Angeles

Today there are more than seven million

Many remember the impact of

the San Fernando tremor

But the 8.3 earthquake

which scientists now predict

will be a shock 800 times as strong

a natural disaster

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