UNITED STATES DEPARTMENT OF THE INTERIOR GEOLOGICAL SURVEY PROCEEDINGS OF CONFERENCE XXVI A WORKSHOP ON "EVALUATION OF REGIONAL AND URBAN EARTHQUAKE HAZARDS AND RISK IN UTAH" August 14-16,1984 SALT LAKE CITY, UTAH SPONSORED BY U.S. GEOLOGICAL SURVEY FEDERAL EMERGENCY MANAGEMENT AGENCY UTAH GEOLOGICAL AND MINERAL SURVEY UTAH DIVISION OF COMPREHENSIVE EMERGENCY MANAGEMENT UNIVERSITY OF UTAH Editors Walter W. Hays and Paula L. Gori U.S. Geological Survey Reston, Virginia 22092 Open-File Report 84-763 Compiled by Car la Kitzmiller and Lynne Downer This report is preliminary and has not been edited or reviewed for conformity with U.S. Geological Survey publication standards and stratigraphic nomenclature. The views and conclusions contained in this document are those of the authors and should not be interpreted as necessarily representing the official policies, either expressed or implied, of the United States Government. Any use of trade names and trademarks in this publication is for descriptive purposes only and does not constitute endorsement by the U.S. Geological Survey. Reston, Virginia 1984 (!) rxi TABLE OF CONTENTS PAGE BACKGROUND INFORMATION AND SUMMARY OF THE WORKSHOP Summary and Background for Workshop on "Evaluation of Regional and Urban Earthquake Hazards and Risk in Utah" Walter Hays and Paula Gori Introduction....................................................... 1 Justification for Studying the Wasatch Front....................... 4 Cummulative Impact of Prior Workshops.............................. 5 Decis ionmaking and Earthquake Hazards.............................. 5 Workshop Strategies................................................ 8 Plenary Sessions................................................... 10 Discussion Groups.................................................. 11 Special Sessions................................................... 12 Conclusions, Recommendations, and Commitments...................... 13 Acknowledgments.................................................... 15 Draft Work Plan for the Wasatch Front.............................. 17 Research Goals, Objectives, and Tasks of the Program Element "Regional Earthquake Hazards Assessments: Wasatch Front, Utah".. 22 Summaries of Preceding Workshops and Knowledge Utilization Activities....................................................... 45 Evaluation of the Workshop on Regional and Urban Earthquake Hazards and Risk in Utah: Analysis and Response of Participants Sallie Marston....................................................... 48 REPORTS OF DISCUSSION GROUPS 1) Synthesis of Geologic, Geophysical, and Engineering Data for Evaluation of Earthquake Hazards and Risk in Utah.................... 54 2) Ground Motion Modeling and Loss Estimation in Utah................... 63 3) Information Systems.................................................. 67 4) Implementation Options Available in Utah............................. 70 EVALUATION OF EARTHQUAKE HAZARDS AND RISK ALONG THE WASATCH FRONT, UTAH Seismicity and Earthquake Hazards of Utah and the Wasatch Front: Paradigm and Paradox Robert Smith and William Richins..................................... 73 Fault Behavior and Earthquake Recurrence Along the Wasatch Fault Zone David Schwartz, Bert Swan, and Lloyd Cluff...........................113 Liquefaction Potential and Slope Stability, Wasatch Front Area Loren Anderson.......................................................126 The Ground-Shaking Hazard Along the Wasatch Fault Zone, Utah Walter Hays and Kenneth King.........................................133 Wasatch Front Hazards Information System Arthur Tarr and Don Mabey............................................148 RESPONDING TO THE EARTHQUAKE HAZARDS IN UTAH A Prospective Assessment for Recovery Following a Major, Damaging Utah Earthquake Charles Thiel........................................................151 Preparedness Planning Along the Wasatch Front for Earthquakes and Other Natural Hazards Ralph Find lay........................................................190 IMPLEMENTATION OF SPECIFIC ACTIONS TO REDUCE POTENTIAL LOSSES FROM EARTHQUAKE HAZARDS IN UTAH Lifelines in an Urban Post-Earthquake Environment Anshel Schiff........................................................203 Review of the Accomplishments and Recommendations of the Utah Seismic Safety Council Delbert Ward.........................................................208 Architectural Actions to Improve Seismic Resistance Christopher Arnold...................................................221 Examples of Earthquake Hazards Mitigation Techniques Available to Planners and Decisionmakers William Kockelman....................................................226 GEOLOGICAL AND GEOPHYSICAL STUDIES IN THE WASATCH FRONT AREA Near-Surface Faulting Associated with Holocene Fault Scarps, Wasatch Fault Zone, Utah: A Preliminary Report Anthony Crone and Samuel Harding.....................................241 Contemporary Vertical Tectonics Along the Wasatch Fault Zone Measured By Repeated Geodetic Leveling Spencer Wood.........................................................269 Constraints on the In-Situ Stress Field Along the Wasatch Front Mary Lou Zoback......................................................286 Earthquake Behavior in the Wasatch Front Area: Association with Geologic Structure, Space-Time Occurrence, and Stress State Walter Arabasz.......................................................310 Investigations of an M^ 4.3 Earthquake in the Western Salt Lake Valley Using Digital Seismic Data James Pechmann and Bergthora Thorbjarnardottir.......................340 Fluid Pressure, Temperature, and Composition at Depth on the Wasatch Fault, Utah William Parry........................................................366 11 Investigation of Historical Seismicity in the Salt Lake City Portion of the Wasatch Front Region of Utah Using Documentary Sources Sherry Oaks and Ted Algermissen......................................384 Preliminary Investigations of Late Quaternary Slip Rates Along the Southern Part of the Wasatch Fault Zone, Central Utah Michael Machette.....................................................391 EARTHQUAKE POTENTIAL AND GROUND MOTION/LOSS ESTIMATION MODELING Earthquake Recurrences Estimated by Calibrating Qualitative Geologic Rate Estimates David Perkins and Paul Thenhaus......................................407 Strain Rates in Utah from Seismic Moments, Paleoslip, and Geodetic Surveys Robert Smith, Paul Eddington, and L. L. Lillian Leu..................422 Analysis of Earthquake Ground-Shaking Hazard for the Salt Lake City- Ogden-Provo Region Maurice Power, David Schwartz, Robert Youngs, and Bert Swan..........438 Probabilistic Risk Assessment for the Utah Multi-Hazards Project Mart in McCann........................................................456 Near-Source Attenuation of Strong Ground Motion for Moderate to Large Earthquakes An Update and Suggested Application to the Wasatch Fault Zone of North-Central Utah Kenneth Campbell.....................................................483 An Effort to Determine Poisson's Ratio In Situ for Near-Surface Layers Don Steeples, Richard Miller, and Kenneth King.......................500 Extensional and Compressional Paleostresses and Their Relationship to Paleoseismicity and Seismicity, Central Sevier Valley, Utah Ernest Anderson and Theodore Barnhard................................515 Preliminary Estimates of Geographic Variation in Relative Ground Shaking in the Wasatch Front Urban Corridor Albert Rogers, David Carver, Walter Hays, Kenneth King, and Robert Miller........................................................547 Ground Failure Hazards and Risks: Considerations and Research Needs Applicable to Utah Jeffrey Keaton.......................................................557 Application of Ground Failure Maps to Earthquake Hazard Reduction Leslie Youd..........................................................568 A Plan for Evaluating Hypothesized Segmentation of the Wasatch Fault Russell Wheeler......................................................576 111 EARTHQUAKE HAZARD INFORMATION NEEDED BY PLANNERS AND DECISIONMAKERS Special Session Introduction William Kockelman and Genevieve Atwood...............................606 Land Use Planning Tools: Information Needs for Assessing Implementation Feasibility Patricia Bolton, Marjorie Green, and Susan Heikkala..................615 User Needs as Identified by the Utah Multihazards Project Wesley Dewsnup ......................................................631 The Need for Integrated Multihazard Analysis and Mapping Merril1 Ridd.........................................................634 Earthquake Programs of Private Businesses and Industries Jeanne Perkins.......................................................637 A Lesson Learned from the Idaho Earthquake Hazards Mitigation Effort: The Need for Earthquake Planning Scenarios and the Needed Information They Could Provide Clark Meek...........................................................642 Earth Science Information Needs of Planners and Policymakers in Larimer County, Colorado Robert Alexander..................................................... 647 Earthquake Information Needs of Local Governments Steven French........................................................658 Legal Issues Related to Hazard Mitigation Policies James Slosson........................................................665 Special Session: Needs Identified Genevieve Atwood and William Kockelman...............................669