Mapping for Resilience: Final Report – Understanding the Cascadia Megaquake and Tsunami

by Joseph Frombaugh Posted on
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Original Hypothesis

The Pacific Northwest is at significant risk from the future Cascadia Megaquake and Tsunami, and effective mapping using GIS can enhance disaster preparedness by identifying evacuation routes and highlighting infrastructure vulnerabilities. My hypothesis was that GIS technology, combined with community-led mitigation efforts, could substantially reduce the potential loss of life and property.

Research Journey

Through a series of blog posts, I documented my research and mapping efforts to understand the Cascadia Subduction Zone and its potential impacts. My journey involved:

  1. Understanding the Threat: The Cascadia Subduction Zone is a 700-mile fault line capable of generating a magnitude 9.0 earthquake and a massive tsunami. This event, expected every 300-500 years, poses severe risks to coastal communities. I explored historical data and geological evidence to understand the scope of the disaster.
  2. DOGAMI’s “XXL” Tsunami Inundation Zones: Using data from the Oregon Department of Geology and Mineral Industries (DOGAMI), I analyzed inundation zones for an “XXL” tsunami scenario. These zones represent worst-case scenarios for tsunami reach, emphasizing the need for precise evacuation planning and robust mitigation infrastructure.
  3. Case Studies of Seaside, Oregon, and Westport, Washington: These towns exemplify proactive disaster preparedness. Seaside has invested in a new school campus outside the inundation zone to provide refuge during a tsunami, while Westport has developed a tsunami tower—the first of its kind in the United States. Both towns have detailed evacuation routes and public education programs.
  4. Mapping Evacuation Routes: Using ArcGIS, I created evacuation maps to visualize safe pathways from high-risk zones to safe areas. These maps incorporated elevation data, proximity to tsunami inundation zones, and existing road networks. This process highlighted the importance of accessible evacuation options, particularly for vulnerable populations.

Conclusions and Lessons Learned

Key Findings

  1. Preparedness is Crucial: Towns like Seaside and Westport demonstrate that early investments in infrastructure and planning can save lives.
  2. GIS as a Tool for Resilience: GIS technology proved indispensable in visualizing risks, planning evacuation routes, and communicating potential hazards to communities.
  3. Community Involvement: Effective disaster mitigation requires collaboration between government agencies, scientists, and local residents.

Reflections

My work reaffirmed the value of spatial analysis in disaster management. Mapping not only informs policy decisions but also empowers communities to take action. By creating these maps, I hope to contribute to a broader effort to enhance resilience in the face of the Cascadia Megaquake and Tsunami.

This project has deepened my understanding of how GIS can bridge the gap between scientific research and actionable community resilience strategies.

References

  1. DOGAMI data for tsunami inundation zones.
  2. U.S. Geological Survey (USGS) for earthquake and tsunami risk data.
  3. Local government resources from Seaside, Oregon, and Westport, Washington, detailing evacuation infrastructure and planning efforts.