The greatest hazard facing the Oregon coast is a Cascadia Subduction Zone (CSZ) earthquake and tsunami that could occur at any time. It is important that all Oregonians understand and are prepared for this. The Oregon Coastal Management Program (OCMP) is coordinating with coastal communities to help them prepare for a local Cascadia Subduction Zone (CSZ) tsunami through land use planning. This work uses tsunami inundation and evacuation maps produced by the Oregon Department of Geology and Mineral Industries (DOGAMI). The maps allow communities and planners to understand their risk and vulnerability to a local tsunami event. When they understand the vulnerabilities, they can look for ways to improve evacuation, and implement land use strategies to improve community resilience. 'Resilience' is the ability of a community to "bounce back" after a disaster. This type of land use planning can influence the development of the landscape over time. When development occurs with consideration and understanding of tsunami hazards, it can improve both the short- and long-term resilience of a community.
OCMP is leading this effort in partnership with DOGAMI. Funding for this important work is made possible through grants from the National Oceanic and Atmospheric Administration's (NOAA) Office for Coastal Management and National Tsunami Hazard Mitigation Program.
Learn more about earthquake and tsunami hazards.
Learn more about natural hazard mitigation planning.
Mapping produced by DOGAMI is the definitive source of information for the identification of areas subject to tsunami inundation. DOGAMI has produced several map products depicting tsunami inundation for the Oregon coast:
- Tsunami Inundation Maps (TIM's) depict the projected tsunami inundation zone from five different magnitude seismic events and resulting tsunamis: small, medium, large, extra-large, or extra extra-large (S, M, L, XL, XXL) events. These different modeled events are associated with differing levels of risk in terms of the relative likelihood of tsunami inundation.
- Tsunami Evacuation Maps are public products designed to direct visitors and residents away from low-lying areas in the event of a tsunami. They depict three color zones: orange for the largest expected distant tsunami (from Alaska); yellow for the largest expected local tsunami; and green for safety (or high ground).
- Beat the Wave: DOGAMI has completed detailed tsunami evacuation modeling for several coastal communities to determine the best routes to "beat the wave" to safety for a local tsunami event. These maps show areas of expected tsunami inundation, the most efficient routes to reach safety, and how fast one must travel to get there.
Components of Current Tsunami Land Use Work:
- Beat the Wave evacuation modeling:
Socioeconomic analyses of tsunami impacts:
- Provides a detailed evacuation map showing minimum pedestrian speeds and routes to reach safety;
- Can help analyze various evacuation scenarios and prioritize improvements;
- Provides detailed information needed to make land use financing techniques work, such as legal exactions;
- Key component for Tsunami Evacuation Facilities Improvement Planning (comprehensive approach to improving a community’s evacuation routes and facilities).
Tsunami land use resilience measures:
- Provides an assessment of the numbers of people, businesses, and critical facilities (schools, hospitals, police/fire stations) in the Cascadia tsunami inundation zone;
- Provides an assessment of the various population groups living in each community, in order to better understand potential evacuation challenges that could affect different population groups;
- Provides structure-level analyses of potential damage (including costs) to individual buildings, impacts to businesses, and fatality estimates for each community.
- Assist local governments in the drafting and adoption of comprehensive plan and development code provisions utilizing OCMP's Tsunami Land Use Planning Guide. These measures may include:
- Requirements for evaluating current development proposals in relation to tsunami evacuation risk;
- Assessments to identify and prioritize evacuation infrastructure improvements;
- Options to impose additional land use limitations in the highest risk areas (such as prohibiting new critical and essential facilities);
- Long-term relocation strategies and related infrastructure investments in high risk areas;
Many of the coastal communities doing this work are receiving a technical assistance grant from OCMP. Click here for more information about our coastal planning grant program.