Applications of Research from the U.S. Geological Survey Program, Assessment of Regional Earthquake Hazards and Risk Along the Wasatch Front, Utah U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1519 Contributions from Utah Geological Survey, Utah Division of Comprehensive Emergency Management, University of Utah, and Utah State University vum: f- COVER PHOTOGRAPH Oblique aerial view looking east at theWasatch fault zone below Spanish Fork Peak near Mapleton, Utah. The fault is the high west-facing curvilinear scarp. The flat bench at the base of the faceted range front is the Bonne ville shoreline. Geological studies at this location indicate that the most recent large magnitude surface faulting earthquake occurred about 650 years ago. (Photograph by Woodward-Clyde and Associates, 1969.) Applications of Research from the U.S. Geological Survey Program, Assessment of Regional Earthquake Hazards and Risk Along the Wasatch Front, Utah Edited by PAULA L. GORI U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1519 Contributions from Utah Geological Survey, Utah Division of Comprehensive Emergency Management, University of Utah, and Utah State University This report documents how pertinent information about earthquake hazards along the Wasatch Front, Utah, was transferred to researchers, public officials, design professionals, land-use planners, and emergency managers as part of the U.S. Geological Survey's effort to mitigate the effects of earthquake hazards. UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON: 1993 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 Library of Congress Cataloging in Publication Data Applications of research from the U.S. Geological Survey program, assessment of regional earthquake hazards and risk along the Wasatch Front, Utah/edited by Paula L. Gori. p. cm. (U.S. Geological Survey professional paper ; 1519) Includes bibliographical references. 1. Earthquake hazard analysis Wasatch Eange (Utah and Idaho) 2. Seismology Wasatch Eange (Utah and Idaho) 3. Natural disasters Utah. 4. Faults (Geology) Wasatch Eange (Utah and Idaho) 5. Geology, Stratigraphy. 6. Geology Wasatch Eange (Utah and Idaho) I. Gori, Paula. II. Series. QE535.2.U6A66 1993 551.2'2'09792201-dc20 91^180 CIP For sale by U.S. Geological Survey, Map Distribution Box 25286, Bldg. 810, Federal Center Denver, CO 80225 PREFACE In 1983, the U.S. Geological Survey (USGS) targeted the Wasatch Front, Utah, for a multiyear program that focused on earthquake hazards research and hazards reduction. This report represents the transfer of pertinent information about earthquake hazards along the Wasatch Front to researchers, public officials, design professionals, land-use planners, and emergency managers as part of the USGS effort to mitigate the effects of earthquake hazards. An earlier report, USGS Professional Paper 1500, "Assessment of Regional Earthquake Hazards and Risk Along the Wasatch Front, Utah, A-J and K-Z," contained the results of much of the research and experiences of the program from 1983 to 1988. This report contains the results of research and experiences undertaken during the later phases of the Wasatch Front program. Professional Paper 1500 defined the nature of the earthquake hazards in the Wasatch Front, including tectonic framework and earthquake potential, ground- shaking hazards and the estimated losses, and the use of earthquake hazards information for urban and regional planning. This Professional Paper comple­ ments the first report by presenting examples of how the research and experi­ ences were applied at the local level. Application of scientific information to further earthquake hazards reduction was one of the goals of the USGS program in the Wasatch Front. Presented in this report is an explanation of how new information was incorporated into policy and practice and how new information about the earthquake hazards was specifically applied in Utah. This report, therefore, is a compendium of informa­ tion developed at the local level to reduce the earthquake hazards of surface-fault rupture, landslides and debris flows, liquefaction, and tectonic subsidence with an explanation of the methodologies followed to encourage the organization and application of scientific information. The authors who have contributed to this report represent the many disciplines and levels of government that participated in this multidisciplinary cooperative program. Paula L. Gori, Editor in CONTENTS Page Page Preface.............................................................................. Ill A Mapping of Ground-Shaking Intensities for Salt Lake Interactive Workshops: Essential Elements of the Earthquake County, Utah Hazards Research and Reduction Program in the By Philip C. Emmi................................................ 91 Wasatch Front, Utah Introduction.............................................................. 91 By Paula L. Gori....................................................... 1 Acknowledgments...................................................... 91 Introduction.................................................................. 1 Measurement of Ground Shaking.................................. 91 Utah Regional Earthquake Hazards Assessment Program.... 2 General Model for the Assessment of Ground-Shaking The Role of Interactive Workshops................................... 3 Hazards ............................................................. 95 Interactive Workshops in Utah ........................................ 5 Points of Departure Data and Relationships ................. 96 Conclusion.................................................................... 10 Comparison of Alternative Methods.............................. 100 References ................................................................... 11 References ............................................................... 106 Appendix A.................................................................. 12 Reducing Earthquake Hazards in Utah: The Crucial Appendix A: Abbreviated Description of the Modified Connection Between Researchers and Practitioners Mercalli Intensity Scale ........................................ 109 By William J. Kockelman........................................... 16 Appendix B: The Interpretation of Technical Statements Introduction and Purpose................................................ 16 of Risk............... ................................................ 111 Acknowledgments.......................................................... 22 Appendix C: Use of Computer Mapping and GIS Toward the Connection in Utah ....................................... 22 Methodologies..................................................... 112 Translation for Practitioners............................................ 26 Wasatch Front County Hazards Geologist Program Examples of Successful Translation in Utah....................... 30 By Gary E. Christenson ......................................... 114 Transfer to Nontechnical Users........................................ 40 Introduction.............................................................. 114 Examples of Successful Transfer in Utah........................... 45 Acknowledgments...................................................... 115 Evaluation and Revision ................................................. 64 Description of the Program ......................................... 115 Conclusion.................................................................... 67 Accomplishments....................................................... 117 References ................................................................... 68 Evaluation and Suggestions......................................... 119 Public Perceptions of the Implementation of Earthquake Conclusions............................................................... 119 Mitigation Policies Along the Wasatch Front in Utah References ............................................................... 120 By Gary E. Madsen, Loren R. Anderson, Jerold H. Surface-Fault Rupture: A Guide for Land-Use Planning, Barnes, and Genevieve Atwood ................................... 75 Utah and Juab Counties, Utah Introduction.................................................................. 75 By Robert M. Robison ........................................... 121 Acknowledgments.......................................................... 76 Introduction.............................................................. 121 Methodology................................................................. 76 Acknowledgments...................................................... 122 Results of the Surveys ................................................... 76 Characteristics of the Wasatch Fault Zone ..................... 122 Application of Research Findings to Implementation of Consequences of Surface-Fault Ruptures and Reduction Earthquake Hazard Reduction on the Wasatch Front.... 80 of Hazards.......................................................... 125 References ................................................................... 80 Use of Special Study Zone Maps .................................. 125 A Data Base Designed for Urban Seismic Hazards Studies Scope of Site Investigations......................................... 125 By Arthur C. Tarr ....................................................