A Crack in the Edge of the World (51 page)

But, having said this, Charles Richter did try to make his scale somewhat user-friendly. He worked his mathematics around the idea that the number zero should represent the smallest kind of episode that could be recorded on a seismometer; that values of around 3 would describe the smallest earthquakes that could be felt; and that values between 5 and 7 would represent the strongest ruptures that the average Californian—and all the early calculations of this very Californian man were specifically aimed at the fears and apprehensions and past experiences of the locals, his neighbors—might ever experience in a lifetime.

The logarithmic nature of the scale can render it unfamiliar to most. A magnitude 5 earthquake is not twice as great as a magnitude 2.5, for example. But 900 earthquakes of magnitude 5, or thirty of magnitude 6, would be needed to release as much energy as a single quake of magnitude 7. And, while small-magnitude earthquakes can be very inefficient at releasing the stored-up energy in the earth, large-magnitude quakes can be devastatingly good: The 7.9 earthquake in San Francisco released 10
¹⁷
joules of stored energy in the sixty seconds of ground shaking—and only a very small fraction of that went into making the ground move. Large earthquakes have the power to move mountains, quite literally—and Charles Richter's scale can show how, and offer figures to prove it.

In conclusion: Intensity requires an audience; magnitude requires only the divining powers of machines. The numbers that are offered up by each kind of measurement, and that bear no relation to the other numbers that are offered up for assigning numerical value to the world's various physical phenomena, inhabit a curious half world of their own, all invented by geophysicists and each enjoying its own utility. To tell of the intensity of a quake is to relate rather romantically something local and subjective and vaguely arbitrary; to record the magnitude, on the other hand, is to note something that is arithmetical, absolute, and able to be presented for instant comparison. So, while intensity may seem the more amusing indicator to relate, it has to be admitted that earthquake magnitude, and the Richter scale that since 1935 has recorded it, are the stuff of history, and of science, and a matter of record. And thus, in summary, they, the magnitude readings, are of a rather more lasting value. Which is why Rossi, Forel, as well as Medvedev, Sponheuer, and Karnik are known by a very few; and why Charles Richter is a famous figure, now and forever more.

This stratigraphical diagram gives the presently recognized time span of each geological interval for the 545-million-year period, or eon, that can be readily dated and delineated using fossils, and which is known as the Phanerozoic.

The earth is, however, very much older than the life that has existed on it, having been created some 4,200 million years ago. This vastly long earlier period, not shown in the diagram, is divided by geology into two eons: the Proterozoic (which stretches from 2,500 million years to the start of the fossil-rich Cambrian, 545 million years ago) and the Archaean (dating from the estimated coalescence of the solid earth, 4,200 million years ago, up to the beginning of the Proterozoic).

Please note the different scales used in the diagram.

For further information on a time scale, which is constantly being refined, I suggest visiting the website of the International Commission on Stratigraphy at www.stratigraphy.org.

O
NE AFTERNOON IN THE EARLY SPRING OF 2003, AS I
was beginning to plan the research for this book, I remarked to my companion that to get the flavor of the city that would be its central subject I really ought to move there. We talked for a while about the details, and then we agreed: It all seemed like an eminently sensible plan.

The idea then hung in the air, but for no more than five minutes, for suddenly the telephone rang. There was an unfamiliar voice, a man's, on the other end. He introduced himself as Scott Rice, chairman of the Department of English at San Jose State University in Northern California.

He was calling, he said, to ask if the following winter I might like to move across to San Jose and teach there for a few months. It was, I thought to myself, the most uncannily propitious of synchronicities. And so it is with pleasure that I perform here my first and happiest duty—to record to whoever (or whatever) it was that prompted Professor Rice to call me that day my most earnest and sincere thanks.

For I did indeed take up the offer: I drove out west and I spent a small part of those first four months of 2004 teaching, lecturing, and generally bloviating to a most intelligent and attentive group of students in California. And then, from the pleasant flat in central San Francisco with which the university supplied me, I spent the rest of my time exploring and riffling my way through the manifold fascinations with which the cities of California, and the disaster that afflicted and otherwise affected them a century ago, are so richly endowed.

Without the university's help it would have been all so very much more difficult. I am grateful also to the friends I made at the university: Alan Soldofsky (who is academically fascinated by that most geologically minded of California poets, Robinson Jeffers), Mitch Berman, Paul Douglass, and the delightful Connie Lurie, whose generosity funded my visiting professorship to the university of which she is one of the more stellar alumni.

GIVEN THE SEISMIC PROPENSITIES
of California, it is hardly surprising that so many geologists are drawn there, most hovering as moths around the ever-flickering flame of the San Andreas Fault. They were universally helpful to me, enthusiastically sharing their knowledge and research, and trying hard to keep me from committing elementary blunders—and if I have failed them then it is my failure, not theirs. Many work for or with the U.S. Geological Survey office at Menlo Park, making up what is surely the jolliest coven of bureaucrats within this or any other government—and I happily record my thanks in particular to Mary Lou Zoback and Mark Zoback, Andy Snyder, Carol Prentice, William Ellsworth, and Leslie Gordon. Susan Hough, who also works for the USGS but on the Caltech campus in Pasadena, was enormously helpful, and as a writer of popular geology books also was particularly sympathetic to the challenges of conveying complex seismic matters in an assimilable way: I owe Susan, now a good friend for life, a formidable debt.

I would also like to record my gratitude to other geologists elsewhere: Eldridge Moores and John Dewey at the University of California, Davis; Tina Niemi, who is an expert in digging trenches into the San Andreas Fault but who is nominally based far away at the University of Missouri in Kansas City; Bill Cotton, who is deeply involved with the geological bizzareries of the town of Portola Valley; Ann Crawford at the Geological Society of America in Boulder, Colorado; Peter Haeussler of the USGS office in Anchorage, Alaska; Ted Nield of the Geological Society of London; Anthony Lomax, whose recent interests from his headquarters in France include new research on the location of the 1906 earthquake's hypocenter; the authors Damien Nance and Brendan Murphy, who offered me help on the origins of the names of early supercontinents; and John Rogers, who named the first and oldest of them Ur, from his department at the University of North Carolina.

A brief and unexpected encounter in an elevator in a Dallas hotel with Dave Ruppert, an archaeologist with the National Park Service in Denver, led me to two further Park Service scientists based at Yellowstone, Hank Heasler and John Varley, who helped me understand the significance of the variations in the periodicity of the geysers there. And Fred Ganders, a botanist at the University of British Columbia, advised me on the yerba buena plant and the man who first named it.

Harold Brooks of the San Francisco office of the American Red Cross, and his colleague on the other side of the Bay, Jean Nickaloff, were both immensely helpful in showing me their plans for dealing with any future citywide disasters; as was Jim Aldrich of the City of San Francisco's Office of Emergency Services, whose latest plans are necessarily the most sophisticated of all those that have been prepared for the skein of cities that lie between Santa Rosa and San Jose, and which can be expected to suffer the consequences of any dramatic slippage on the various faults that run beneath them.

I am grateful also to Claire Perry, Curator of American Art at the Cantor Center at Stanford University; to Martin Uden, British Consul General in San Francisco, and his assistant, Julia Cottam, who uncovered original correspondence from the diplomats who were based in the city at the time of the earthquake; to Harold Hallin of Lake Tahoe, Nevada, an insurance underwriter whose syndicate was involved in writing 1906 policies; and to my San Jose student Pat O'Laughlin of Los Gatos, who kindly introduced me to a number of his friends who had papers, images, memories, and opinions related to the seismic history of the region.

By chance I found that my apartment in San Francisco was just one floor above the flat belonging to California's most renowned living historian and author, Kevin Starr, and I am happy to record my thanks to him for his many courtesies and for his advice (and for his forbearance whenever I had heavy-footed friends over for tea).

The staff at Acorn Books was universally helpful in supplying me with long-forgotten publications that related to the 1906 events. I hope they consider that I, as customer, once helped them, too, if in a small way, on that occasion when about six of us felt obliged to jump on and subdue an extremely tall but somewhat deranged gentleman who, after lunching unwisely one day on a cocktail of unfamiliar chemicals, decided to come in and try to wreck the shop. We pinned him to the ground while waiting for the police to come, and—though I hardly recommend it as an ideal way to break the ice between bookseller and customer—we came to know one another extremely well in consequence, and discounts were offered once in a while.

And, finally, among those who gave professional help, I must give enormous thanks to Ron Henggeler, whose peerless performance as a waiter at the Big Four Restaurant on Nob Hill is matched only by his talent as an artist and his infectious enthusiasm for collecting San Francisco memorabilia. Not a single aspect of Bay Area life—from the debates over the siting of wartime antiaircraft batteries to the menu choices for lunches served at the Sutro Baths, from the mating habits of sea lions to the casualty tolls from earlier earthquakes—has ever escaped Ron's jackdawlike appetite, and his collections are immense and impeccably organized. He was kind enough to allow me to borrow from almost all and everything he possessed—film clips, books, magazines, paintings, vinyl records—and never once pressed me to return them until I was good and ready to do so. Ron is an enormously proud waiter, as he should be, and for anyone in need of some arcane fact about old San Francisco, I recommend a visit to his restaurant and a seat in his station. But do please remember the
pourboire
.

MATTHEW SCHECHMEISTER
of Stanford and Amy Biegelsen of Richmond, Virginia, helped with many aspects of my researches, and did so ably and with great energy. I wish to thank my friend Renee Braden of the National Geographic Society archives, together with her admirable colleague Mark Jenkins. Other old friends, Kate Schermerhorn and Matt Clarke, recorded much of my West Coast research on film, in the probably vain hope that one day someone, somewhere, might be interested in seeing just how a book of this kind is made: That they put up with my whims so cheerfully for so long is testament to their undeniable talent as filmmakers. Richard Price of Robinson, Illinois, offered many valuable suggestions for improving the text of the paperback edition of the book; and Steven Marshank of Ashland, Oregon, made some very useful comments that I similarly incorporated into my revision. Sophie Purdy, as is her wont, helped tirelessly with this book, just as she helped with the three that immediately preceded it: My debt to her is incalculable.

MY SUGGESTION
that I write this book was accepted, warmly and eagerly, by that most legendary of editors, Larry Ashmead—and though Larry retired during the writing of it, he never once abandoned his paternal interest in the project. My fondest hope is that when he sees it now, he will feel content with the way it all turned out. If he does, then that will in no small part be to the team that succeeded him—especially Henry Ferris, the wonderfully capable editor who agreed to take on the project in New York, together with Peter Hubbard, his meticulous assistant. In London my editor, Mary Mount, offered a thousand and one suggestions for improving the text: I believe I agreed with almost all of them, and am grateful to her for making them, and so tactfully and kindly, too. Donna Poppy and Sue Llewellyn remain the most faithful of copy editors, brilliant and faultless; and Peter Matson and Bill Hamilton—helped by their respective assistants Nina Aron and Ben Mason—remain the finest agents for which an author could possibly wish. I raise a glass to each of you.

As I do, finally, to my partner, Elaine, who came to hear in a couple of years more about strike-slip faults and ophiolite sequences and the Chinese poetry of Angel Island than any person of reasonable firmness might expect to hear in a couple of lifetimes. She took it all with great good cheer and in a spirit of amused tolerance, and remained in the best of good humor all the time that I was hunched silently over my keyboard, ignoring all around me. So for allowing me the peace and for keeping content all the time: a thousand thanks, my dearest Elaine. You've been an absolute brick.

ALQUIST-PRIOLO
This term, used with easy familiarity by many Californians today, refers to the 1972 Earthquake Fault Zoning Act, which was sponsored by the Democrat state senator for Santa Clara, Alfred Alquist, and the Republican state assemblyman for Ventura, Paul Priolo. The act compelled the state geologist to determine where all California's geological faults were located; imposed strict limits on the types of buildings that could be erected in seismic hazard zones that ran along them; and in time demanded that maps be prepared showing builders and real estate agents—as well as insurers—which parts of the state were relatively seismically safe and which were likely to be unsafe. Alquist-Priolo maps, as they are known, now run into the hundreds and are essential for anyone thinking of building or buying in the Golden State.