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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."
What do earthquakes need to be warned early about?
1985, Mexico City, buildings collapsed when the center of the earthquake was 400 km away. That one was unusual but it shows what's possible.
The other thing you can do with 10-20 seconds of warning is apply emergency brakes on the bullet trains, which I believe Japan has arranged to do.
"... 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
The collapsed Cyprus freeway was in Oakland. It's believed that earthquake waves travel horizontally through the crust and can also be reflected off of harder layers further down. If the original wave and the reflected wave harmonize they can be extremely destructive even many miles from the epicenter.
It's simple: I demand prosecution for torture.