Environmentally Critical Areas Update

New Geologic Hazard Areas

The City of Seattle has designated the Seattle Fault zone and areas of the city that are at risk from tsunamis, seiches, and lahars as environmentally critical areas. These designations will assist citizens in understanding the threat posed by these hazards. No additional regulation of these new environmentally critical areas is currently being proposed.

Background Materials

• Adopted Geologic Hazard Areas Ordinance (March 2007): This update designated the Seattle Fault zone and areas of the city that are at risk from tsunamis, seiches, and lahars as environmentally critical areas.
• Geologic Hazard Areas Director’s Report (February 2007): This report provides supporting information on the proposed geologic hazard area ordinance.
• Supplemental Geologic Hazard Areas Best Available Science Report (February 2007): This report provides a compilation and review of the supplemental best available scientific information that has been considered in the proposed code update for new geologic hazard area designations.
• Links to Maps & Reports Referenced in Proposed Ordinance and Best Available Science Report:
• • Seattle Fault Zone – Seattle Fault Zone Map
  • Tsunami Hazard - Tsunami Hazard Map of the Elliott Bay Area
  • Lahar Hazard - Volcano Hazards from Mount Rainier Report
  • • Full Report
    • Map C & D referencing Seattle