:26:12
This is earthquake country.
:26:14
a great fault tears 700 miles
through the crust of California.
:26:19
lt is the San Andeas Fault
:26:22
the classic example of the last
major tectonic process.
:26:27
Beneath us, two great plates
of the Earth's crust
:26:30
are moving and grinding
laterally past one another
:26:34
generating earthquakes
:26:35
in the spasms
of their slow movement
:26:38
To the left, a huge slice
of western California
:26:42
rides the Pacific Plate
as it drifts northward
:26:45
past the American Plate
on the right
:26:51
The fitful movement averages
but two inches a year
:26:54
yet it has already carried
more than 300 miles.
:26:58
And, in 50 million years,
this slice of California
:27:02
including the present sites
of Los Angles and San Diego
:27:07
will be an Arctic island
approaching the Aleutian Trench.
:27:14
North on the fault line stands
a great and beautiful city-
:27:18
San Francisco.
:27:24
In 1 906, a powerful earthquake
and resulting fire
:27:28
leveled this city.
:27:30
Since, the stresses
have steadily accumulated
:27:33
in the fault
:27:35
Yet, when the San Andreas
:27:36
launches another
great earthquake
:27:38
San Francisco need not die.
:27:42
ln our new awareness
of Earth's forces
:27:44
we have designed our buildings
:27:46
to withstand
the greatest of earthquakes.
:27:49
Already, a new science has taken
the first promising steps
:27:53
in predicting
and controlling earthquakes.
:27:58
Our new theories
of plate tectonics