Kodiak Island Borough Multi-Jurisdictional Hazard Mitigation Plan Update May 2018 Prepared for: Kodiak Island Borough i Table of Contents 1 Introduction ............................................................................................................................ 1 1.1 Hazard Mitigation Planning ............................................................................................ 1 1.2 Planning Requirements ................................................................................................... 2 1.3 Grant Programs with Mitigation Plan Requirements ..................................................... 2 1.3.1 HMA Unified Programs ............................................................................................. 3 2 Prerequisites ........................................................................................................................... 4 2.1 Adoption by Local Governing Bodies and Supporting Documentation .......................... 4 3 Community Description .......................................................................................................... 5 3.1 Local History .................................................................................................................... 5 3.2 Geology, Geography, and Climate .................................................................................. 7 3.3 Demographics ................................................................................................................. 8 3.4 Economy .......................................................................................................................... 9 3.5 Land Use and Development Patterns ........................................................................... 11 3.5.1 Development Since 2006 ........................................................................................ 14 3.5.2 Future Development Trends ................................................................................... 14 3.6 Property Assessment .................................................................................................... 14 4 Planning Process ................................................................................................................... 15 4.1 Overview of Planning Process ....................................................................................... 16 4.2 2018 Hazard Mitigation Planning Team ....................................................................... 17 4.3 Public Involvement & Opportunity for Interested Parties to Participate ..................... 17 4.4 Incorporation of Existing Plans and Other Relevant Information ................................ 19 5 Hazard Profiles ...................................................................................................................... 20 5.1 Overview of Hazard Analysis ......................................................................................... 20 5.2 Identifying Hazards ....................................................................................................... 22 5.2.1 State of Alaska Hazard Risk Mitigation Plan, 2013 Matrices .................................. 22 5.3 Hazard Identification and Screening ............................................................................. 23 5.4 Hazard Profile ................................................................................................................ 26 5.4.1 Earthquakes ............................................................................................................ 26 5.4.2 Tsunamis ................................................................................................................. 40 i 5.4.3 Volcanic Hazards ..................................................................................................... 53 5.4.4 Landslides ................................................................................................................ 64 5.4.5 Erosion .................................................................................................................... 70 5.4.6 Wildland/Urban Interface Fires .............................................................................. 75 5.4.7 Severe Weather ...................................................................................................... 81 5.4.8 Dam Failure ............................................................................................................. 86 5.4.9 Technological (Transportation, Fuel, and Utilities) ................................................ 95 6 Vulnerability Analysis .......................................................................................................... 108 6.1 Overview of the Vulnerability Analysis ....................................................................... 108 6.2 Vulnerability Analysis: Specific Steps .......................................................................... 109 6.2.1 Asset Inventory ..................................................................................................... 109 6.2.2 Methodology ......................................................................................................... 114 6.2.3 Data Limitations .................................................................................................... 115 6.2.4 Exposure Analysis .................................................................................................. 115 7 Mitigation Strategy ............................................................................................................. 118 7.1 Developing Mitigation Goals....................................................................................... 118 7.2 Identifying Mitigation Actions .................................................................................... 122 7.3 Evaluating and Prioritizing Mitigation Actions ........................................................... 134 7.4 Implementing a Mitigation Action Plan ...................................................................... 135 8 Plan Maintenance ............................................................................................................... 142 8.1 Monitoring, Evaluating, and Updating the MJHMP .................................................... 142 8.2 Implementation Though Existing Planning Mechanisms............................................ 144 8.3 Borough Capability Assessment .................................................................................. 145 8.4 Continued Public Involvement .................................................................................... 152 9 References .......................................................................................................................... 154 ii Table of Tables Table 1—Kodiak Population and Housing Summary ...................................................................... 9 Table 2—Jurisdiction per Capita Income ...................................................................................... 10 Table 3—Land Ownership on Kodiak Island Borough .................................................................. 11 Table 4—2017 Kodiak Island Borough Assessor’s Office Property Values ................................... 14 Table 5—2018 Hazard Mitigation Planning Team ........................................................................ 17 Table 6—Public Involvement Mechanisms ................................................................................... 17 Table 7—Identification and Screening of Hazards ....................................................................... 21 Table 11—Hazard Matrix .............................................................................................................. 22 Table 12—Previous Occurrences from 1978 to Present .............................................................. 23 Table 8—Hazard Probability Criteria ............................................................................................ 25 Table 9—Hazard Magnitude/Severity Criteria ............................................................................. 25 Table 10—Largest Recorded Earthquakes .................................................................................... 26 Table 11—Probable Impacts of Major Earthquakes for Kodiak Island Borough .......................... 38 Table 12—USGS Estimated Earthquake Return Periods .............................................................. 45 Table 13—Probable Impacts of Major Tsunamis .......................................................................... 52 Table 14—USGS Volcanic Alert Levels for People on the Ground ................................................ 61 Table 15—USGS Volcanic Alert Levels for Air Traffic .................................................................... 61 Table 16—Probable Impacts of Landslides ................................................................................... 68 Table 17—Probable Impacts of Erosion Events ............................................................................ 73 Table 18—Kenai/Kodiak State Protection Area Fire Data. ........................................................... 78 Table 19—Probable Impacts of Wildland/Urban Interface Fires ................................................. 79 Table 21—Ice Hazard Data for Kodiak Island Borough ................................................................. 83 Table 20—Probable Impacts of Severe Weather Events .............................................................