Seismic Hazards in Seattle
The city of Seattle is built on a major fault zone known as the Seattle Fault. Geologists believe that earthquakes of magnitude 6.5 or greater occur on this fault every 1000 years, the last one occurred 1100 years ago, leaving Seattle 100 years overdue for a massive earthquake.
When the next earthquake of magnitude 6.5 or greater occurs on the Seattle Fault, thousands of people will die, 10's of thousands will be injured, hundreds will be trapped, over 190,000 buildings will be damaged or completely destroyed, there will be over 100 major fires, bridges will collapse, all major interstates will be closed or partially closed for months, and hospitals nearest to the fault may be damaged to the point that they are unable to provide aid to the injured.
The earthquake will cause a tsunami in Puget Sound that will be the equivalent of dropping a raging river on Pioneer Square, plus most lower elevation areas from Bainbridge Island to Tacoma will be suddenly flooded by the colossal wave. There will also be tsunamis and landslides around Lake Washington.
Seattle will not recover for many years, maybe never.
1. Earthquake Engineering Research Institute: Scenario for a Magnitude 6.7 Earthquake on the Seattle Fault
2. U.S. Geological Survey: Seattle Fault Zone - seismic profiles
3. The Seattle Times: Major quake could launch deadly tsunami