By Andrew Nusca
Posting in Cities
Here's how the world's first early warning earthquake detection system kicked into gear before an 8.9-magnitude quake struck Japan on Friday.
But some residents knew it was coming before it happened.
A fantastic primer by Juro Osawa in the Wall Street Journal details how the world's first early warning earthquake detection system kicked into gear before the big one struck the nation's coast.
The system, developed by Japan's meteorological agency in 2007, was able to detect a shockwave near the 'quake's seismic center and relay that message over television, radio and mobile phone.
Here's how it works:
- Seismometers detect the first shockwave.
- Computers analyze the wave and estimate how powerful the second one will be.
- If that wave is estimated to be more powerful than a certain threshold ("lower 5" on the local scale), an alert is issued.
It's simple enough, but it's a critical step so that companies -- think utilities, petrochemical plants, rail operators and others -- can shut down facilities and minimize damage.
Make no mistake -- the warning is issued mere seconds before the earthquake actually occurs. But it's just enough to make a difference for those further away from the seismic center -- as well as initiate a ripple effect across the globe.
More on Japan's preparedness via the New York Times:
In the country that gave the world the word tsunami, Japan, especially in the 1980’s and 1990’s, built concrete seawalls in many communities, some as high as 40 feet. In addition, some coastal towns have set up networks of sensors that can sound alarms in every residence and automatically closed floodgates when an earthquake strikes to prevent waves from surging up rivers. Ports are sometimes equipped with raised platforms.
Update: Here's a great Q&A on the subject with Brian Shiro at Popular Mechanics.
Related on SmartPlanet:
- Why Americans aren't prepared for the next mega-disaster
- Video: Detecting earthquakes before they happen
- Japanese nuclear plant damaged in earthquake, needs coolant
- Japan's strong building codes keep millions safe
- In pursuit of a sustainable, resilient city
Mar 10, 2011
@Hates Idiots Trains are decelerating when the earthquake hits. Seeing how they have 1 HSR train confirmed destroyed and 4 others still missing, I question how good their systems really were. How can the sensors that cause trains to decelerate when the earthquake hits, stop them from being destroyed or going missing, I question how good your judgement really is about this?
"Friday's quake was 7 on that scale, and the system sent out the warning message 8.6 seconds after it detected the very first shock wave." Honey, there's an earthquake coming; get ready! When. Eight seconds. Aaaaaahhhhhiiiieeeeee.....
They need designs that are inherently stable when not producing power. All current reactor designs require artificial cooling when offline, not producing power. They are, by design, wasteful and inherently dangerous.
Knowing Japan is seismometrically active, and they have a number of nuclear generating plants on or near faults, why don't they maintain large tanks (10,000 gallons ?) of concentrated boric acid solution for each reactor? In a strong earthquake, especially followed by Tsunamis, severe damage to controls, cooling systems and shut-down apparatus should be a given. Use flex piping every so many meters in coupling the boric acid solution to the reactor. There should be a cut-off valve(s) between the primary coolant loop and the reactor, such that the system to slow or stop the nuclear reaction is controlled in its own cooling loop, separated from the rest of the apparatus. Then open additional supplies of coolant when the "stopper" solution gets too hot. If the secondary coolant loop is functional, use that to cool the boric acid solution. What's the additional cost, vs. the cost of a runaway reactor and its health concerns and clean-up costs.
I heard these sensors were supposed to be hooked into Japans high-speed train system. It is supposed to trigger a power shutdown of the trains, they are all electric, so they are decelerating when the earthquake hits. Seeing how they have 1 HSR train confirmed destroyed and 4 others still missing, I question how good their systems really were.
It's stupid! I built 1 device then discard it. The speed of EQ sound is about 9km per second depending type of soil. if you are at epicenter, then having 1/10 second to escape. It's impractically, only enough time for few steps. if you are at 100km away, then having 11 seconds to escape, but most EQs wont affect that far, so you dont need to run. It's stupid idea.