
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

No comments:
Post a Comment