Submarine Landslides: Selected Studies in the U.S
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Submarine Landslides: Selected Studies in the U.S. Exclusive Economic Zone Edited by W.C. SCHWAB, H.J. LEE, and D.C. TWICHELL U.S. GEOLOGICAL SURVEY BULLETIN 2002 U.S. DEPARTMENT OF THE INTERIOR BRUCE BABBITT, Secretary U.S. GEOLOGICAL SURVEY Dallas L. Peck, Director Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Government UNITED STATES GOVERNMENT PRINTING OFFICE: 1993 For sale by U.S. Geological Survey, Map Distribution Box 25286, Bldg. 810, Federal Center Denver, CO 80225 Library of Congress Cataloging in Publication Data Submarine landslides : selected studies in the U.S. exclusive economic zone 1 U.S. Department of the Interior, Geological Survey ; edited by W.C. Schwab, H.J. Lee, and D.C. Twichell. p. cm. - (U.S. Geological Survey bulletin ; 2002) Supt. of Docs. no.: 119.3:2002 1. Mass wasting-United States. 2. Marine sediments-United States. I. Schwab, William C. 11. Lee, Homa J. Ill. Twichell, David C. IV. Series. [QE598.5.U6] 557.3 S-dc20 [551.3'071 91-33678 CIP FOREWORD With each passing year, the United States becomes increasingly dependent upon resources from the oceans. Historically, the sea has provided food resources, recreational resources, and a defensive barrier in times of war. During the last few decades, we have turned to the sea to provide other resources such as oil, gas, and construction aggregate which had been almost exclusively extracted from onshore areas. With an ever-growing population demanding more resources to sustain a high quality of life, the United States will have to turn more frequently to the oceans to meet its increasing requirements for fresh water, energy minerals, industrial minerals, agricultural minerals, waste disposal, recreational diversions, military exercises, and other activities. All this must be accompanied and balanced with environmental concerns. Recognizing the growing importance of the oceans to the future of the United States, President Reagan in 1983 expanded the United States to include those parts of the oceans extending 200 miles off our shores. This enormous new territory, the Exclusive Economic Zone (EEZ), is over 3 million square nautical miles in size which is about 30 percent large than the land area of the United States. The United States Geological Survey (USGS) through its Offshore Geologic Framework program was directed by the President and the Congress to explore the sea floor of this new frontier. In partnership with colleagues from other Federal agencies, the States, academia, industry, and scientists from the international community, the USGS began a program in 1983 to map the EEZ. To date, these reconnaissance-scale studies have mapped approximately 2 million square nautical miles of the EEZ and unveiled a fascinating, but extremely complex, sea floor. These discoveries hold the promise of potential resources that ultimately will help meet the needs of all Americans. This promise will be realized, however, only through continued research, technology advancement, and informed decision making. Although our studies discovered significant potential resources, they also identified geologic processes that not only threaten the availability of these potential resources but also threaten human life directly. This volume is dedicated to increasing the understanding of one such process-submarine landslides. The authors focus on documenting our new understanding of the geologic processes involved in submarine landslides and the consequences of these processes. Submarine landslides fall within a general category marine geologists call geohaz- ards. To evaluate fully the significance of any geohazard, it is necessary to develop an understanding of the basic geological processes involved as well as the geographic distribution, frequency of occurrence, scale, magnitude, and consequences of the processes. All these topics and more are covered as the authors share their insights into submarine landslides occurring in diverse geologic settings throughout the EEZ from New England to Hawaii, from the arctic to the tropics, and from shallow water to deep ocean basins. Without question, submarine landslides involve significant geologic processes which must be understood and documented for policy makers to make informed decisions as to when and how the marine resources within the United States EEZ are to be exploited. This volume is a substantial and unique contribution to expanding the knowledge base of submarine landslides. Gary Hill Foreword Ill CONTENTS Foreword III Submarine Landslides: An Introduction 1 By H. J. Lee, W.C. Schwab, and J.S. Booth U.S. Atlantic Continental Slope Landslides: Their Distribution, General Attributes, and Implications 14 By J.S. Booth, D.W. O'Leary, Peter Popenoe, and W.W. Danforth Submarine Mass Movement, a Formative Process of Passive Continental Margins: The Munson-Nygren Landslide Complex and the Southeast New England Landslide Complex 23 By D.W. O'Leary The Cape Fear Landslide: Slope Failure Associated with Salt Diapirism and Gas Hydrate Decomposition 40 By Peter Popenoe, E.A. Schmuck, and W.P. Dillon Ancient Crustal Fractures Control the Location and Size of Collapsed Blocks at the Blake Escarpment, East of Florida 54 By W.P. Dillon, J.S. Risch, K.M. Scanlon, P.C. Valentine, and Q.J. Huggett Tectonic and Stratigraphic Control on a Giant Submarine Slope Failure: Puerto Rico Insular Slope 60 By W .C. Schwab, W.W. Danforth, and K.M. Scanlon Slope Failure of Carbonate Sediment on the West Florida Slope 69 By D.C. Twichell, P.C. Valentine, and L.M. Parson Slope Failures in an Area of High Sedimentation Rate: Offshore Mississippi River Delta 79 By J.M. Coleman, D.B. Prior, L.E. Garrison, and H.J. Lee Salt Tectonics and Slope Failure in an Area of Salt Domes in the Northwestern Gulf of Mexico 92 By B .A. McGregor, R.G. Rothwell, N.H. Kenyon, and D.C. Twichell Slope Stability in Regions of Sea-Floor Gas Hydrate: Beaufort Sea Continental Slope 97 By R.E. Kayen and H.J. Lee Mass Movement Related to Large Submarine Canyons Along the Beringian Margin, Alaska 104 By P.R. Carlson, H.A. Karl, B.D. Edwards, J.V. Gardner, and R. Hall Comparison of Tectonic and Stratigraphic Control of Submarine Landslides on the Kodiak Upper Continental Slope, Alaska 117 By M.A. Hampton Submarine Landslides That Had a Significant Impact on Man and His Activities: Seward and Valdez, Alaska 123 By M.A. Hampton, R.W. Lemke, and H.W. Coulter Processes Controlling the Style of Mass Movement in Glaciomarine Sediment: Northeastern Gulf of Alaska 135 By W.C. Schwab and H.J. Lee Contents V Liquefaction of Continental Shelf Sediment: The Northern California Earthquake of 1980 143 By M.E. Field A Submarine Landslide Associated with Shallow Sea-Floor Gas and Gas Hydrates off Northern California 151 By M.E. Field and J.H. Barber, Jr. Sur Submarine Landslide, a Deep-Water Sediment Slope Failure 158 By C.E. Gutmacher and W .R. Normark Seismically Induced Mudflow in Santa Barbara Basin, California 167 By B.D. Edwards, H.J. Lee, and M.E. Field Submarine Landslides in a Basin and Ridge Setting, Southern California 176 By M.E. Field and B.D. Edwards Giant Volcano-Related Landslides and the Development of the Hawaiian Islands 184 By W.R. Normark, J.G. Moore, and M.E. Torresan Submarine Slope Failures Initiated by Hurricane Iwa, Kahe Point, Oahu, Hawaii 197 By W.R. Normark, Pat Wilde, J.F. Campbell, T.E. Chase, and Bruce Tsutsui VI Contents SUBMARINE LANDSLIDES: SELECTED STUDIES IN THE U.S. EXCLUSIVE ECONOMIC ZONE Edited by W.C. Schwab, H.J. Lee, and D.C. Twichell Submarine Landslides: An Introduction By H.J. Lee, W.C. Schwab, and J.S. Booth INTRODUCTION "mass movement"). At Valdez, a large portion of a subma- rine delta-front failed during the Alaska earthquake and Consider these events: In the late afternoon of March slipped into the bay, carrying with it the town's waterfront 27, 1964, one of the most violent earthquakes of all time and generating massive waves. During Hurricane Camille, rocked southern Alaska. In the community of Valdez, the large waves generated by the storm loaded the weak shortly after the shaking began, a cargo ship unloading at sea-floor muds, causing them to fail and move downslope. the town dock began to toss violently, with vertical motion On the Grand Banks, the magnitude 7.2 earthquake caused in excess of 10 m (meters) and rolls of 50". Next, the docks slope failures on the continental slope and rise. Some of vanished into turbulent water. The entire waterfront fol- these slope failures transformed into high-velocity turbidity lowed, along with warehouses, a cannery, heavy equip- currents that traveled over 720 km (kilometers) from the ment, and 30 people. Ten-meter waves propagated back and source area, breaking communication cables along the way. forth across the bay on which Valdez is situated, surging Off the coasts of the Hawaiian Islands, the remains of giant over 500 m inland and flooding much of the town. For slope failures have been found using a modern side-looking months following these catastrophic events, the shore area sonar system. Some are more than 200 km long with near Valdez continued to subside. volumes up to 5,000 km3. The great displacement of the In August 1969, Hurricane Camille, one of the landslide blocks from their original source suggests that century's most intense hurricanes, struck the coast of some of the failures were cataclysmic events, capable not Louisiana. At an oceanographic station near the South Pass only of removing landmass from the islands' coastlines but portion of the Mississippi Delta, wave heights of 21 to 23 m also of generating tremendous sea waves.