With much of the southeastern side of the country grappling with an unprecedented range of catastrophic damage and a high number of deaths from Hurricane Helene, it’s …
This item is available in full to subscribers.
We have recently launched a new and improved website. To continue reading, you will need to either log into your subscriber account, or purchase a new subscription.
If you had an active account on our previous website, then you have an account here. Simply reset your password to regain access to your account.
If you did not have an account on our previous website, but are a current print subscriber, click here to set up your website account.
Otherwise, click here to view your options for subscribing.
* Having trouble? Call our circulation department at 360-385-2900, or email our support.
Please log in to continue |
|
With much of the southeastern side of the country grappling with an unprecedented range of catastrophic damage and a high number of deaths from Hurricane Helene, it’s natural to wonder about the unique vulnerabilities in Washington state, specifically earthquakes.
The state has been working to better understand the potential for earthquake damage to the state’s public schools for years. The School Seismic Safety Project (SSSP) is a multi-year statewide effort undertaken by researchers with the Washington Geological Survey (WGS) and staff with the Office of Superintendent of Public Instruction (OSPI) to assess the seismic vulnerability at K-12 schools and communicate these results to school districts, policy makers, and members of the public.
As part of the project, the state releases “Site Class” assessments of school buildings. In 2019 to 2021, three local schools were part of the updated assessment — Blue Heron Middle School, Brinnon Elementary School, and Chimacum Junior/Senior High School.
Site class reports estimate how local soils amplify earthquake-induced ground shaking based on how fast seismic (shear) waves travel through the upper 100 feet of soil.
Site class reports have been approximated for the entire state of Washington, but these predictions are not always accurate where geology is complex. Researchers with the project report that the site class measured for the School Seismic Safety Project accounts for geologic complexity which state researchers say is more accurate than statewide approximations.
The project is ongoing and new data and reports are updated as they are completed.
Below is a summary of each of the schools and where it falls in terms of an Earthquake Performance Rating System (EPRS). A one-star rating indicates a risk of collapse in multiple or widespread locations. A two-star rating indicates a risk of collapse in isolated locations. A three-star rating indicates a loss of life is unlikely. Three stars is the target rating for schools.
Blue Heron Middle School
Two stars
On Dec. 14, 2019, a team from the Washington Geological Survey conducted a seismic survey at Blue Heron Middle School. The team learned the school is built on stiff soil, which would amplify ground shaking relative to rock. The team also learned that the school is sitting on Holocene artificial fill and modified land. Around the school, the team mapped Pleistocene continental glacial drift, consisting mostly of gravelly silt with drop stones and layers of gravel, sand, silt, and clay. In the event of an earthquake, this soil stands a very low chance of liquefaction, but has the potential for violent ground shaking.
In 2021, the Blue Heron Middle School main building received a two-star EPRS (Earthquake Performance Rating System) structural safety rating. The rating system is used to gauge a building’s safety in the event of an earthquake. A three-star rating is recommended for schools.
Brinnon Elementary School
One star
On Nov. 14, 2019, a team from the Washington Geological Survey conducted a seismic survey at Brinnon Elementary School. The team learned the school is built on soft rock or very dense soil, which would amplify ground shaking relative to rock. The team also learned that the school is sitting on Quaternary alluvium, consisting mostly of boulder, cobble, and pebble gravel and sand with Pleistocene continental glacial drift soil to the north.
In the event of an earthquake, this soil stands a moderate to high chance of liquefaction and the has the potential for violent ground shaking. The school is also within five miles of an active mapped fault.
In June 2021, the Brinnon Elementary School Main Building received a one-star EPRS rating.
Chimacum Junior/Senior High School
Three one-star ratings, and one two-star rating
On Oct. 11, 2020, a team from the Washington Geological Survey conducted a seismic survey at Chimacum Junior/Senior High School. The team learned that the school is built on stiff soil, which would amplify ground shaking relative to rock. The team also learned that the school is sitting on continental glacial drift consisting predominately of pebble to cobble gravel and sand. To the southeast, the team mapped marshes and bogs consisting of peat, muck, silt, and clay. In the event of an earthquake, this soil stands a low chance of liquefaction but has the potential for violent ground shaking. The schools are also within five miles of an active mapped fault.
In June 2021, Chimacum school buildings received three one-star EPRS ratings and one two-star rating. The north wing of Building 100 received a one-star rating.