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An Early Warning System For Earthquakes
Iphtashu Fitz writes "Would 15 seconds be enough warning time to prepare for an earthquake? It certainly wouldn't be long enough to evacuate from where you live, but it may be just long enough to get out of a building or brace yourself in a doorframe or under a solid desk. Italian scientists may have discovered a way to measure the initial shockwave of an earthquake two seconds after it starts, and from it predict the extent of the destructive secondary wave that will follow. It typically takes twenty seconds for the secondary wave to spread 40 miles, so sensors that can transmit warnings at the speed of light may provide just enough warning before a major quake for people to brace themselves. Even more importantly, such a warning could allow for utilities like gas companies to close safety valves, preventing potential fires or explosions in the aftermath of the quake."
(I'm not an expert on earthquakes, but 40 miles seems like a long way for the earthquake to travel.)
There would still be gas in the main lines, how would shutting a safety valve keep a broken pipe from leaking gas already in it?
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My geology professor has gone over it again and again, Radon could potentially be an early warning system in some cases. Naturally the stuff leaks out of the ground, before an earthquake more of it is supposed to come out due to the shifting of the ground up to the earthquake. This could be months, days, minutes that this is detectable. Someone with a better understanding please correct anything and add to this.
What do earthquakes need to be warned early about?
"... brace yourself in a doorframe ..."
this is a myth. The only thing this acomplishes is broken fingers.
It stems from an observation from a red cross worker after a earthquake in mexico.(I think 1950ish.)
That archtecture of the entrance way was an adobe arch. Arches are very strong, as opposed wooden square door frames.
The Kruger Dunning explains most post on
Would 15 seconds be enough warning time to prepare for an earthquake?
Nope. But a few hours to a few days would be lots better.
is barely enough time to evacuate your bowels - let alone prepare for a large quake.
I thought the high speed trains in Japan would stop in the event of an earthquake (before the earthquake actually hit them), http://en.wikipedia.org/wiki/Shinkansen
"In the event of an earthquake, an earthquake detection system can bring the train to a stop very quickly"
Anyway, the idea of a broadcast system to warn of an earthquake is pretty obvious, the engineering task of doing it right without false positives is pretty difficult I bet.
ElarmS.
While the article is quite light on details, much work has been done in this area, by groups such as ElarmS in California, if your interested in the methodology take a look at Allen's paper "Rapid magnitude determination for earthquake early warning (a 7 pg. PDF) which is reasonable understandable by lay persons if you skip through the math, yet still informative for people in the field.
Apocalypse Cancelled, Sorry, No Ticket Refunds
"... brace yourself in a doorframe ..."
this is a myth. The only thing this acomplishes is broken fingers.
A very dangerous myth, too. Most of the deaths in Loma Prieta may have resulted from this myth.
There were 57 deaths attributed directly to the earthquake, and 42 of them were in the Cypress Street Viaduct collapse.
At the start of the earthquake, the drivers stopped. Because of the myth, most of them tried to stop under the arches. When the strucutre collapsed, the arches came all the way down to the pavement, pancaking the cars beneath them, while the regions between the arches had enough space that it was possible, in many cases, to survive the collapse itself.
- - - -
Of course a lot of the deaths there are attributable, not just to the quake, but also to governmental interference with volunteer rescue attempts.
Most of those who survived the initial collapse were still trapped in their cars or the structure itself. When the quake hit virtually all of the the nearby citizens dropped what they were doing (along with any inter-group animosity) and immediately began rescue efforts. (A notable part of this was workers at a nearby warehouse improvising an elevator using a dumpster and a forklift.) The pulled quite a few out of the collapsed structure's "sandwitch" in the first half-hour or so (at considerable risk to themselves, especially given the risk of further collapse or rolling debris due to aftershocks). Then the authorities arrived.
The police kicked them out and cordoned off the area to await the official first responders. They eventually arrived - around sundown. Then they had insufficient light (given the power failure) and mainly waited around further for portable lighting to arrive. It was several hours before rescue attempts, with a smaller force of official rescuers, resumed. (Of course by then the "golden hour" had long since expired and those who had been in shock were now dead or beyond hope.)
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
Ah but which building designs would fare better in a hurricane or tornado? Flooding? We have more than just earthquakes for natural disasters...
This whole idea sounds pretty shaky.
Have you read my journal today?
...or you could and up being a crippled stud.