Thursday, November 13, 2008

Earthquake Precautions and Judging Sources of Information

"When it strikes at 1000 local time, millions of participants across the region will 'drop, cover and hold on' - drop to the ground, take cover under a sturdy desk and hold on until the shaking stops."

(BBC news story on a planned massive earthquake drill in southern California)

Not long ago, I came across a fairly detailed discussion of earthquake precautions, somewhere online; unfortunately I no longer remember where. The author appeared to be well informed, with extensive experience in dealing with disasters.

According to him, "take cover under a sturdy desk" is lethally mistaken advice. The sturdy desk, table, or whatever is likely to have its less solid parts crushed, and you, under it, will in turn be crushed by its more solid parts. Where you want to be is next to the sturdy desk or equivalent--ideally, I suppose, between two of them--so that you end up with at least one end of the chunk of the ceiling that fell on you held up by the solider part of the desk, and you under it and uncrushed. He had similar critiques, along essentially the same lines, for other parts of the standard advice.

I have no independent information on the author's expertise and do not even remember where I saw the information. Nonetheless, I am on the whole more inclined to believe him than to believe the sources of the advice reported in the BBC story. Why?

There are basically three ways of judging sources of information. One is internal evidence--does the author sound like a competent, well informed person who takes reasonable care to make sure that what he says is true? A second is external evidence about the information--does it fit other things I have reason to believe are true? A third is authority--do I have good reason to believe that the source of the information is reliable?

The earthquake advice I read passed the first test and, to the extent I could apply it, the second--it was at least consistent with the relevant geometry and physics, and what little I know of the construction of ceilings and the appearance of collapsed buildings. I had no easy way of verifying the author's claimed expertise, so could not apply the third.

The advice reported by the BBC, at least in the forms have seen it in the past, passes none of the tests. It is presented in a "this is official information, believe it" form, with none of the explanations and qualifications that signal a source taking care not to overstate its claims. It is routinely offered as advice to schoolchildren, presumably the ones most likely to have a convenient desk available to hide under--and my observation of school desks suggest that they are unlikely to have legs strong enough to bear the weight of a collapsed roof. The source is typically not a single, identifiable expert but the sort of bureaucratic organization that sets up an earthquake drill for five million people or generates civil defense instructions to be distributed to schoolteachers and read to children. My experience with the information produced by such organizations in other context is that it reflects less a concern with being right than a concern with not admitting to having been wrong.

Absent further information, I don't plan to hide under a desk if there is an earthquake--especially not under a classroom desk, if I happen to be in a classroom at the time. Are there any readers out there who can point me at better sources of information on the subject?
[Commenters pointed me at what is probably the piece I remember--on my son's blog. The ultimate source appears to be an article, "Triangle of Life," by Doug Copp. Snopes is critical of Copp. Looking at both of the pieces they link to (Red cross and Turkish) that critique Copp's arguments, I find their arguments rather less convincing than his; their strongest point is that building collapse is more likely in the third world disasters his arguments are largely based on than in a country like the U.S., where buildings are more solidly constructed, making optimal precautions different here.

I have not checked out the links Snopes provides to pieces that attack Copp rather than his arguments.]


Unknown said...


Type in the google bar

earthquake triangle

and you will find a lot of information and controversy

Best regards

Anonymous said...

Here ?

Matt Brubeck said...

According to the American Red Cross:

Recently, the American Red Cross became aware of a challenge to the earthquake safety advice "Drop, Cover, and Hold On." This is according to information from Mr. Doug Copp, the Rescue Chief and Disaster Manager of American Rescue Team International (a private company not affiliated with the U.S. Government or other agency.) He says that going underneath objects during an earthquake [as in children being told to get under their desks at school] is very dangerous, and fatal should the building collapse in a strong earthquake. He also states that "everyone who gets under a doorway when a building collapses is killed." He further states that "if you are in bed when an earthquake happens, to roll out of bed next to it," and he also says that "If an earthquake happens while you are watching television and you cannot easily escape by getting out the door or window, then lie down and curl up in the fetal position next to a sofa, or large chair." These recommendations are inaccurate for application in the United States and inconsistent with information developed through earthquake research. Mr. Copp based his statements on observations of damage to buildings after an earthquake in Turkey. It is like "apples and oranges" to compare building construction standards, techniques, engineering principles, and construction materials between Turkey and the United States.

More from the American Red Cross and

I wonder if the real reason you're more inclined to believe the "Triangle of Life" claim is your innate contrarian streak. The rest sounds like rationalization.

dWj said...

Being under a desk would, of course, protect you from minor building damage. As for collapse, I expect there's nothing much you can do about it, and telling people to hide under a desk is like having them put their shoes through the X-ray machine at the airport. I'm sure the officials view saving lives as a laudable goal, but it's not the only one.

Glen said...

The official advice was probably pretty good in the days before the invention of safety glass.

Anonymous said...

I suspect that the advice to schoolchildren to shelter under a desk dates from WWII, a time when school desks were really solid, with heavy steel or wrought iron frames, which would not fail even if loaded by a collapsed building, but would leave the child in a clear protected volume. At that time, the advice was probably good.

Mike Huben said...

"my observation of school desks suggest that they are unlikely to have legs strong enough to bear the weight of a collapsed roof"

Where else do you propose 30 students are going to be? What else could give them ANY protection in the classroom?

I'd also point out that a single desk wouldn't support a collapsed roof, but 30 probably could.

If I was going to criticize these suggestions, I'd point out that it's very hard to get underneath the one piece desk/seat combos that are so common in schools.

Indeed, if anything, this might make an argument that for civil defense purposes we should require furniture to be suitable for taking shelter during earthquakes.

Anonymous said...
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Anonymous said...

Why not go outside of the building your in? There are many things that can fall on you inside a building; as well as a ruptured gas line that could explode causing a fire!

Anonymous said...

Has anyone ever been hurt in an earthquake by holding on to a pole driven into the ground deeply or holding on to a tree trunk with many strong roots; away from falling objects or falling buildings? Ideally, being on board a flight would be the best protection of all the precautions available; which would save your life!