Thursday, June 19, 2008

Earthquake Safe Havens a Non-Starter

There's a little discussion following Ana-Marie's posting below in which Garry brings up the notion of building "safe haven" spaces from earthquakes. I think that this is a non-starter. The ONLY possible safe haven for 1,000 children in a school building is the classrooms themselves.

Before the design, engineering and construction problems I can see several very serious problems with the notion of designing and building earthquake-safe havens:

1. There is no evidence that those subject to strong shaking can go anywhere at all. Most people report that they can't move anywhere safely. So there's no option but for the whole building to be strong enough not to collapse. (The only exception are those very far from the epicenter who may be able to get an early warning from primary waves).

2. For schools it doesn't work just because of the density of occupancy. You'd have to build another place as big as a school to accommodate 1,000 children in a safe haven - so the school itself has to be the safe haven.

3. Suppose that people survived in the thousands in life safe voids, by design or even by accident. Judging by the evidence from both Kashmir and Weichuan, we'd have to be honest and let people know that life-safe voids will not be uncovered within the golden 72 hours for survival... "Lucky" people probably did survive in these places - just to perish there later, unrescued...

4. Even if we could anticipate places where search and rescue will find survivors, we can't responsibly tell people to do something to get to those spots until we first ascertain that such advice would not do more harm than good. This applies equally to the ideas of "safe havens" and "life-safe voids":

Take these photos as an example.
Just because search and rescue workers can prove that they save more people near the outer walls of collapsed buildings does not mean that everyone should get near outer walls. Just because "outside" away from the building is safer than inside, does not mean that everyone should run outside. In both of these building, drop cover and hold would have been the safest thing to do. If people had congregated by the outer walls they would have fallen to their deaths. If they had run outside, they would have been smothered by falling debris.

So the question is not "What could have been done to save people in the buildings with the most fatalities?" The question has to be "What can be done to eliminate fatalities and reduce injuries?" The latter requires a much broader perspective and a research method that that looks at the currently safe sites as well as the most hazardous sites.

I don't think the "cost savings" idea for building earthquake-safe havens works either. I would bet that it would be very hard to find a poor surviving parent in China who believes that they could not afford to build their child's school a safe school.

Indeed we are all agreed that there is a LOT more to learn... about being able to anticipate collapse patterns, about how long it takes buildings to collapse, about the differential rates of deaths and injuries in heavily damaged vs. collapsed buildings, about what is the safest course of action for everyone who is going to feel the shaking and therefore follow whatever advice it is that we promote.

Let's see who wants to step up to fund this research, and pursue it systematically!

P.S. As for doorways - the biggest problem is that they are all so different, depending on construction and placement. Some offer some protection to one or two people (except for the injuries caused by the door itself swinging), others offer none at all. Doorways are a non-starter for schools no matter what the class size.

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