Tsunami warning and preparedness : an assessment of the U.S. tsunami program and the nation's preparedness efforts

Contents EXECUTIVE SUMMARY 1 SUMMARY 3 1 INTRODUCTION 21 The Tsunami Threat in the United States, 21 Goals and Scope of this Report, 24 The Range of Options Available for Tsunami Hazard Mitigation, 25 Focus on Warning and Preparedness, 25 The Nation’s Tsunami Warning and Preparedness Efforts, 25 National Tsunami Hazard Mitigation Program, 26 NOAA’s Tsunami Program, 28 Assessing the Nation’s Efforts, 30 Challenges to Reducing the Nation’s Vulnerability to Tsunamis, 32 Tying It All Together: Report Roadmap, 35 2 ALIGNING PRIORITIES WITH SOCIETAL RISKS FROM TSUNAMIS 37 Summary, 37 Introduction, 38 Comprehensive Risk Assessment, 40 Tsunami Hazard Assessment, 43 Inundation Modeling, 43 Hazard Maps, 53 Evacuation Maps, 61 Vulnerability Assessment, 65 Population Exposure and Sensitivity, 66 Evacuation Potential, 68 3 EDUCATION AND PREPAREDNESS OF INDIVIDUALS, COMMUNITIES, AND DECISION MAKERS 73 Summary, 73 Introduction, 74 Education of At-Risk Individuals, 75 Factors That Increase the Effectiveness of Education, 75 Understanding the Local Risk Conditions and the Target Audience, 79 Increasing the Effectiveness of Public Education of Tsunamis, 82 C O N T E N T S Community Preparedness Efforts, 86 Developing and Delivering Effective Warning Messages, 92 Developing Effective Messages, 92 Effective Delivery of Warning Messages, 96 Improving Coordination of Preparedness Needs and Evacuation Procedures, 99 Improving Communication Among TWCs and NTHMP Members, 99 Communicating Local Community Needs to NTHMP and the TWCs, 101 Practicing Evacuation Procedures and Protocols, 103 Post-Event Reconnaissance, 106 4 TSUNAMI DETECTION AND FORECASTING 109 Summary, 109 Detection of Earthquakes, 111 Seismic Networks Used by the Tsunami Warning Centers, 112 Algorithms for Estimating an Earthquake’s Tsunami Potential, 114 Potential Use of Earthquake Alerts from the NEIC, 117 Detection of Tsunamis with Sea Level Sensors, 119 The Tsunami Warning Decision Process Before and After Enactment of Public Law 109-424, 119 The Economic Value of the DART Network, 121 Description of the Coastal Sea Level Gauge Network, 121 Adequacy of the Geographical Coverage of the Coastal Sea Level Gauge Network, 128 Reliability of the Coastal Sea Level Gauge Network, 129 Coastal Sea Level Data Processing, 130 Description of the Deep-ocean Assessment and Reporting of Tsunamis (DART) Network, 131 Adequacy of the Geographical Coverage of the DART Network, 132 Reliability of the DART Network, 139 DART Data Processing, 145 Sea Level Data Integration into Other U.S. and Global Observation Systems, 145 Forecasting of a Tsunami Under Way, 147 Instrumental Detection of Near-Field Tsunamis, 151 Research Opportunities and New Technologies, 155 Duration of High-Frequency P-Waves for Earthquake Moment Magnitude Estimation, 156 Hydroacoustic Monitoring of Underwater Geophysical Events, 157 Continuous GPS Measurements of Crustal Movement, 158 Observation of Tsunami Wave Trains with Satellite Altimeters, 160 Tsunami-Induced Sea-Surface Roughness and “Tsunami Shadows”, 161 Direct Recording of Tsunami Waves by Island Seismometers, 161 “Upward Continuation” of the Tsunami Wave and Its Detection in Space, 162 xi Contents 5 LONG-TERM RELIABILITY AND SUSTAINABILITY OF WARNING CENTER OPERATIONS 163 Summary, 163 The Tsunami Warning Centers, 165 Tsunami Warning Center Functions, 167 Tsunami Detection, 169 Tsunami Decision Support, 176 Product Generation and Warnings, 176 Technology Needs, 179 Human Resources, 184 Organizational Structures, 186 Conclusions, 189 REFERENCES 193 APPENDIXES A Examples of Tsunami Sources That Threaten the United States 207 B Review of the Tsunami Warning and Forecast System and Overview of the Nation’s Tsunami Preparedness 217 C Relative Hazards of Near- and Far-Field Tsunami Sources 219 D Available Tsunami Evacuation Maps 223 E Examples of Tsunami Education Efforts 237 F June 14, 2005: A Case Study in Tsunami Warning and Response 243 G Magnitudes from C. Richter to Mwp and the W Phase 249 H Tsunami Earthquakes 257 I Samoan Tsunami 259 J Response to the Chilean-Earthquake Generated Tsunami: The Hawaii Case Study 263 K Acronyms 273 L Committee and Staff Biographies 279