Looking for answers
on tsunami safety
Is the Ocosta Tsunami Evacuation Building as safe as advertised?
I don’t think so.
While the Ocosta school building is cited as a “great advance” in protecting the public, my questions to various officials go unanswered.
After reading a startling report, “Mechanism of tsunami fires after the Great East Japan Earthquake 2011 and evacuation from the tsunami fires,” presented at The 9th Asia-Oceania Symposium on Fire Science and Technology, I viewed the Ocosta building with Google Earth and found, that while Roberts Road West is 40-feet high to the west of the Ocosta Elementary School, Roberts Road quickly drops to 28-feet elevation to the south.
Waters flow around barriers, and we know a megaquake could further drop Westport peninsula by around six feet of elevation.
I discussed the Ocosta building tsunami flow study with its UW professor author and was disheartened to learn that the study was only done in 2-D, not 3-D.
Who decided to limit the study?
This means that the elevation points were done only linearly west to east. Had a 3-D study been conducted it likely would have shown that, as the water rises, the flow would approach the school first from the south, and then, if it was a more serious tsunami, the water would overtop Roberts Road from the west.
But it’s not the rising water alone that creates the problem, it’s the velocity and what it carries.
The Japanese study showed that propane tanks, vehicles and debris often ignited and got pushed up against, and accumulated against, buildings.
The study writes, “In these situations, sparks from metals which collided (with) each other by tsunami and through other scenarios may have ignited leaked combustible gases and gasoline to become fires. These fires spread to combustible materials in and from broken houses, automobiles etc.”
Three of the Japanese tsunami evacuation buildings had to be evacuated because of the fires and smoke, and in one case, gasoline had penetrated the building, then ignited, and blew a third of the roof off. So much for buildings designed with breakaway walls.
A second problem is that nearly all the vehicles at the school would be parked in an arc west to south. Because it only takes three feet of moving water to push a car, and since most of the initial flood would come from the south, most of the vehicles would be pushed against the school.
Thirdly, the evacuation building is connected to the rest of a school but has an outside alcove, and entrance pillars, that will allow floating cars and debris to accumulate within it. The debris accumulation is made worse because the building is angled in such a way as to inhibit flotsam from flowing north past the building.
Since last December I have shared this information with local officials, state representatives, emergency managers and others. The only response has come from the architect and UW professor who conducted the flow study, and sent me a copy. The architect wrote, “While I can see some parallels between the (Japanese) report and the Ocosta project, I do not have enough information nor am I qualified to say how this type of situation would play out at Ocosta given the numerous variables involved.”
More revealing, the UW professor wrote, “you’re absolutely correct to be concerned about burning debris risk at the Ocosta school. Your voicemail mentioned cars in the parking lot and, yes, both the impact of a car on the school as well as ignition of the gasoline is a real concern, too.”
I had made some recommendations on mitigating the threat, one to include raising the roadway to the south to at least 40 feet. Another would be to design some vertical barriers to limit debris flowing against the building. So far … nothing!
There’s an upcoming Tsunami Roadshow at noon on April 11, at the Ocosta school evacuation building. You can bet I’ll be there trying to get answers. If you want answers, I hope you will be too!
Randy Dutton
Montesano
