Vashon Earthquake Study Fact Sheet
VashonBePrepared has conducted an earthquake study estimating casualties and building damage, as well as needs for food and shelter. The study utilized sophisticated computer modeling techniques managed by a team of geologists, disaster planning specialists, and other volunteers. The study examines a range of possible effects from four earthquake scenarios.
Casualties and Damage
• As many as 70 people on Vashon would require some degree of medical treatment, with as many as ten people critically injured or killed by the most severe of the four studied earthquake scenarios.
• About 100 to as many as 250 Vashon buildings would be so severely damaged that they would be uninhabitable. That’s 2% to 5% of all Vashon building stock.
• Between 600 and 1,100 Vashon buildings would be moderately damaged or worse, requiring extensive repairs or completely destroyed - 22% of all Vashon buildings.
• Depending on the scenario, direct economic losses would be at least $41.2 million. Potentially, losses could reach nearly $83 million.
Food and Shelter
• In the immediate aftermath of a daytime earthquake the Island would need to find shelter for a total of 640 to 1,300 people, including those rendered homeless by destruction of their homes and mainland residents stranded by loss of ferry service.
• People in shelters would require between 1,920 and 3,900 meals per day, a total of between 13,000 and 27,000 meals during the first week after the earthquake.
• If ferry service was out for more than a week, food needs would quickly soar as grocery stores and home pantries were depleted. Assuming a two week ferry outage the Island could require as many as 235,000 emergency meals to feed those in shelters as well as the Island’s own population.
Vashon Stands Alone
A study in early 2005 of a 6.7 magnitude earthquake centered on Bellevue clearly showed Vashon could be on its own during a regional disaster. The Seattle Fault Scenario predicted chaos on the mainland, with all available resources being overwhelmed:
• 1,600 deaths and 24,200 injuries. Most hospital facilities heavily damaged.
• 9,700 buildings destroyed and another 29,000 severely damaged.
• Collapsed bridges cutting all six major highways in the Seattle metropolitan area.
• Downtown and Fauntleroy ferry terminals damaged. Port facilities badly damaged.
• Utilities and other lifeline facilities cut in poor soil areas.
See Full Text of Study