Tuesday, May 5, 2009

Tsunami? NOAA's got our back.

There were many things that struck me as odd when I moved to the North Island from Winnipeg when I was eight years old. All the kids in my grade three class called their backpacks "pack sacs", and cutting in line was "budging". But weirdest of all was when the orderly fire drill I had come to know and love morphed into a crawl-on-the-floor, hold-onto-your-desk-and-count extravaganza. Turns out, there was no fire: we were having an earthquake drill!

Earthquake drills are still practiced in schools on the North Island, because here on the Pacific North Coast we are located in a prime earthquake risk zone. Scientists believe that a large earthquake in the Cascadia subduction zone might take place in our lifetime. Along with our fear of earthquakes, comes a fear of the resulting tsunamis.

But fear not, fellow Pacific Coasters! The USA's National Oceanic and Atmospheric Administration has got us covered. Following the disastrous tsunami in South Asia in 2004, the Bush administration authorized a $37.5 million upgrade to NOAA's international tsunami warning system. Last year, the final two buoys in the Deep-Ocean Assessment and Reporting system, or DART2 were deployed. Now there is a network of 39 tsunami-assessing buoys in portions of the Pacific and Atlantic Oceans, the Gulf of Mexico, and the Caribbean Sea.

The idea behind the design of this system seems simple to me, and with the help of this diagram, it becomes even simpler to understand.
First, a passing tsunami creates changes in water pressure;
Next, a bottom pressure recorder monitors changes in pressure, and acoustically sends potential "events" to a surface buoy moored above.
The surface buoy relays information to a communications satellite, and this data is received in a tsunami warning center in the USA. Areas in danger can then be quickly notified.

How long does this process take? “From the time a buoy detects something to the time that information arrives at the warning center is usually less than five minutes from any ocean. Then it takes maybe 10 more minutes to process the data, come up with a determination of threat and send out a response.”1

So the idea is: if ever there is a tsunami about to crash into the Port McNeill harbor, our friends at NOAA and the tsunami warning center will inform us of this fact well in advance of any impending danger. Then, just in case I become blinded by terror and forget to run AWAY from the water, I will be reminded by my local constituency's contribution to the tsunami preparedness effort: tsunami evacuation route signs, pointing UP the hill. Genius.

No comments:

Post a Comment