Earthquake Storms: The Fascinating History and Volatile Future of the San Andreas Fault

352 Pages·2014·7.8 MB·English

by  John Dvorak

EARTHQUAKE STORMS
the fascinating history and volatile future of the san
andreas fault
John Dvorak
Dedicated to my father,
who always has a story to tell,
and to my mother,
who has always had the patience to listen to my father’s stories.
Contents
PROLOGUE: The Swimmer
CHAPTER 1: A Noble Earthquake
CHAPTER 2: No Occasion for Alarm
CHAPTER 3: A Tumult of Motions and Noises
CHAPTER 4: Bridging “the Golden Gate”
CHAPTER 5: Blue Cut and the Mormon Rocks
CHAPTER 6: The Troubled World of Charles Richter
CHAPTER 7: Of Petrol and Pinnacles
CHAPTER 8: A Transformative Idea
CHAPTER 9: To Quake or Not to Quake
CHAPTER 10: Ancient Tremors
CHAPTER 11: Disassembling California
CHAPTER 12: Earthquake Storms
EPILOGUE: Bodega Bay
Image Gallery
Acknowledgments
Index
The whole world quaked …
—Homer, Iliad
Prologue
The Swimmer
Every earthquake is a surprise.
—Anonymous
I
have often wondered—and envied—at the peculiar way Clarence Judson
contributed to the study of earthquakes. A 36-year-old mechanic for United
Railroads in San Francisco, he was following a daily routine of rising during the
darkness of early morning and, after donning a robe, shoes, and a hat, careful not
to wake his wife or two-year-old son or twin infant daughters, setting out for a
brisk swim in the nearby waters of the frigid Pacific Ocean.
It was mid-April and the walk to the shore was a short one. The Judsons had
lived for two years in a modest clapboard house two blocks from the ocean in
what was a sparsely settled development known then and today as Ocean Beach.
On his way, Clarence Judson crossed a recently paved road that city planners
had designated “The Great Highway”—a moniker that it still has today—then
climbed over a short ridge of sand dunes and continued down to the beach.
He disrobed at the edge of the water and watched the waves before he entered.
They were coming in sideways, in broken sets, the larger ones running up high,
then pulling back. Judson later described them as “clawing at the beach.”
He waded into the water up to his armpits and was ready to swim when a
roller, larger than most, lifted him up, then set him down on his feet. A few
moments passed and he prepared himself again to swim when, without warning
and without any visible disturbance on the water surface, a great slap hit him
across his entire body.
The slap stunned him and he started to go under. He struggled and somehow
reached the surface just in time to suffer a second slap, then a third.
Now tumbling and his lungs filling with seawater, he fought desperately, able
to summon enough energy to drag himself up onto the beach. Then the bizarre
and most memorable part of his ordeal began.
Frightened by what had already happened, he tried to run to where his shoes
and hat and robe lay, but discovered his legs refused to work. They shuddered
uncontrollably—and he thought he must be paralyzed.
Surprised when he could move his legs again, he looked down and saw that the
sand directly beneath his feet was filled with a phosphorous glow. Afraid his feet
might be burned, he took off running, noticing that each step produced another
incandescent strike.
When he reached his clothes, he tried to dress but was thrown down as the
ground started to shake violently. This time he realized it was a terrible
earthquake. His thoughts shifted to his family and he knew he had to get back to
them.
The ground shook for almost a minute. As soon as it ended, Judson rose and
dressed and raced back over the ridge of sand dunes and across the new paved
road, which he noticed was badly cracked. He ran at top speed, past houses that
were now tilted, some having shifted off their foundations.
When he arrived home, he found his wife frantic and his children crying. He
tried to calm them, but a rumor soon came from a neighbor that said a giant sea
wave might follow the quake. So the Judsons gathered what they could in
blankets and, carrying these few possessions, joined other neighbors in an
exodus, moving a few dozen blocks inland where they would camp for the next
two nights.
As Clarence Judson and his family and their neighbors made their way, they
could see dark clouds billowing up a few miles to the east. Later that afternoon,
they would learn, as the rest of the world did, that San Francisco had been
crippled that morning by a major earthquake—and that, because gas lines had
been disrupted and chimneys had collapsed and the pipes that were to feed water
to the city had broken, fires were now raging out of control, and the great city,
home of nearly half a million, was burning to the ground.
Even today, much that Judson experienced that April morning in 1906—the
wave slaps, the phosphorescent sand—has not been explained by science, an
indication that our understanding of earthquakes is still in its infancy. And yet
much has been learned since the infamous San Francisco earthquake, much of
that knowledge gained by studying the San Andreas Fault, the same fault that
ruptured that morning more than 100 years ago and caused roadways to crumble
and houses to lean.
It was only after the 1906 San Francisco earthquake that most scientists finally
realized that earthquakes were caused by the sliding of great crustal blocks
against each other and not, as many had favored, by subterranean volcanic
explosions. Four years after the San Francisco disaster, after a detailed study of
the effects of the earthquake had been published, scientists also realized that
earthquakes were powered by the release of elastic energy stored within the
Earth, though how the energy had accumulated would remain a mystery for
another half century. Not until the advent of the theory of plate tectonics in the
1960s would this and many other major mysteries about the Earth be solved.
Plate tectonics—the idea that the Earth’s outer shell consists of a dozen or so
mobile plates that collide or spread apart or slide horizontally past each other—
would explain why earthquakes are so prevalent in California. In short, the
tectonic plate that includes most of the continent of North America is moving,
ever so slowly though constantly, westward, while the one that comprises most
of the Pacific basin is moving, also at an excruciatingly slow pace, to the
northwest. This difference in direction has caused a great fracture to form—the
San Andreas Fault. It was movement along a segment of this fault that caused
the 1906 earthquake.
Running for 800 miles from the redwood forests of Cape Mendocino
southward to the rugged Sonoran Desert on the east edge of the Salton Sea near
the border with Mexico, the San Andreas Fault passes beneath dozens of
communities and close to two of the nation’s largest cities, San Francisco and
Los Angeles. It lies under major highways, pipelines, and crucial aqueducts.
Scores of housing developments have been platted directly over it.
The fault is most readily apparent as an unusual alignment of river systems and
valleys. In northern California, the Gualala and Garcia Rivers lie along it. In
central California, the fault runs through narrow Bear Valley east of Point Reyes
and through the fault’s namesake, the San Andreas Valley. In the southern part
of the state, picturesque Cuddy Valley and Leona Valley and arid Lone Pine
Canyon mark its trend. The fault is responsible for the formation of both Cajon
Pass and San Gregorio Pass, two vital corridors that link Los Angeles with the
rest of North America. It is responsible for several desert oases and its trace can
be seen, with a trained eye, from Palm Springs.
The words “San Andreas” are so well known that they have become
synonymous with the stereotypical fast lifestyle that is California—and with
seismic destruction—though many perceptions about the fault are in error.
Technically, the San Andreas Fault is not the plate boundary between the
North American and Pacific plates; instead, it is a major component of that
boundary. The plate boundary actually reaches across a vast region that stretches
from the Pacific coast to Colorado, New Mexico, and west Texas.
The San Andreas Fault is also a relatively young geological feature—as well
as a transient one—when compared to other major geologic features, such as the
Black Hills of South Dakota, which began to rise about 50 million years ago, or
the basins filled by the Great Lakes, which began to sag hundreds of millions of
years ago. By comparison, the current strand of the fault is a few million years
old. The oldest segments of it are only 25 million years old and can be found in
the mountains north and east of Los Angeles.
And, contrary to popular opinion, a major earthquake along the San Andreas
Fault will not cause California to fall into the ocean. Instead, the San Andreas
Fault and its many subsidiary faults are slowly tearing California apart, so that
much of what is California today will be transformed into a collection of islands
that are destined to be rafted northward across the Pacific.
Of obvious interest and concern is what will happen along the fault in the near
future. On this question, scientists are in agreement: The last few hundred years
have been a period of relative seismic calm in California. The calm cannot last,
because the elastic energy that is building up as the Pacific and the North
American plates grind against each other must be released. And that release can
occur in only one way—as large earthquakes.
We also know from a study of the San Andreas Fault and its many subsidiary
faults—the Hayward Fault, the Hollywood Fault, the Newport-Inglewood Fault,
the San Jacinto Fault—that earthquakes do not occur randomly, nor do they