EarthquakEs Plate Tectonics and Earthquake Hazards EarthquakEs Plate Tectonics and Earthquake Hazards timothy kusky, Ph.D. EARTHQUAKES: Plate Tectonics and Earthquake Hazards Copyright © 2008 by Timothy Kusky, Ph.D. All rights reserved. No part of this book may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage or retrieval systems, without permission in writing from the publisher. For information contact: Facts On File, Inc. An imprint of Infobase Publishing 132 West 31st Street New York NY 10001 Library of Congress Cataloging-in-Publication Data Kusky, Timothy M. Earthquakes: plate tectonics and earthquake hazards / Timothy Kusky. p. cm.—(Hazardous Earth) Includes bibliographical references and index. ISBN-13: 978-0-8160-6462-5 (acid-free paper) ISBN-10: 0-8160-6462-8 (acid-free paper) 1. Earthquakes. 2. Plate tectonics. I. Title. QE534.3.K87 2008 551.22—dc22 2007020832 Facts On File books are available at special discounts when purchased in bulk quantities for businesses, associations, institutions, or sales promotions. Please call our Special Sales Department in New York at (212) 967-8800 or (800) 322-8755. You can find Facts On File on the World Wide Web at http://www.factsonfile.com Text design by Erika K. Arroyo Illustrations by Richard Garratt Printed in the United States of America VB FOF 10 9 8 7 6 5 4 3 2 1 This book is printed on acid-free paper and contains 30 percent post-consumer recycled content. To the Himalayan villagers whose lives were changed by the Kashmir earthquake of October 8, 2005 n  n  n Contents Preface xi Acknowledgments xiii Introduction xv Part I : Plate Tectonics 1 General Earth Structure and Plate Tectonics 3 Physiography: Shape of the Surface of the Planet 4 Historical Development of the Plate Tectonics Theorem 6 Alfred Lothar Wegener (1880–1930) 8 Alexander Logie Du Toit (1878–1948) 11 Plate Tectonics and the Hazardous Earth 12 How Plate Tectonics Works 13 Conclusion 18 2 Divergent Plate Boundaries 20 Divergent Plate Boundary Processes 20 Divergent Plate Boundaries in Continents 21 Kevin C. Burke (1929– ) 22 Modes of Extension 23 Divergent Plate Boundaries in the Oceans 25 Transition from Continental to Oceanic Rifting: The Afar Triangle 26 Conclusion 32 3 Transform Plate Boundaries and Transform Faults 34 Transform Margin Processes 35 Transform Boundaries in the Continents 36 Transform Boundaries in the Oceans 40 Tanya Atwater (1942– ) 41 Conclusion 42 4 Convergent Margins 44 Convergent Plate Margin Processes 46 Southern Alaska’s Convergent Margin 46 Arcs 50 Variations between Different Types of Convergent Margin Arcs 52 Collisions 56 The Tibetan Plateau 59 Conclusion 63 Part II : Earthquakes 5 Earthquakes 67 Areas at Risk for Significant Earthquakes in the United States 69 Origins of Earthquakes 74 Method of Locating Epicenters Using Three Intersecting Circles 76 Measuring Earthquakes 78 Earthquake Magnitude 80 Conclusion 82 6 Earthquake Hazards 84 Ground Motion 85 Ground Breaks 88 Mass Wasting 89 Liquefaction 90 Changes in Ground Level 92 Tsunami and Seiche Waves 92 Damage to Utilities (Fires, Broken Gas Mains, Transportation Network) 96 Conclusion 97 7 Earthquake Prediction, Preparation, and Response 98 Earthquake Statistics 98 Predicting Earthquakes 99 China’s Liaoning Earthquake: Successful Earthquake Prediction 102 Seismic Hazard Zones and Risk Mapping 103 Paleoseismicity: Understanding Ancient Earthquakes 104 Architecture and Building Codes 106 Agencies That Deal with Earthquakes 107 Earthquake Response 107 Utilities Infrastructure and Emergency Response 108 Earthquake Readiness 108 Conclusion 110 8 Descriptions of Earthquake Disasters 111 Earthquakes That Struck Convergent Margins 112 Earthquakes That Struck Transform Margins 128 Earthquakes That Struck Intraplate Regions and Divergent Margins 131 Conclusion 139 Summary 140 Appendix 143 Glossary 144 Further Reading and Web Sites 153 Index 161