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GPS Could Speed Tsunami Warning
wwood_98 writes to tell us that Wired is running a story about how GPS could serve more than its traditional role. From the article: "International organizations like the Pacific Tsunami Warning Center, or PTWC, in Hawaii currently depend on coastal seismic stations to record deep-sea earthquakes that could cause giant waves. But according to Jeff Freymueller, a geophysicist at the University of Alaska Fairbanks, data from GPS receivers could provide quicker, more accurate estimates of the magnitude of a tsunami-causing quake, buying time for evacuation. Freymueller presented his findings at this week's American Geophysical Union conference in San Francisco."
Excellent, if you live in a coastal city, you'll get to know that you have 20 minutes left to live...
According to the SAS Survival manual by John Weisman - if a Tsunami is inbound your best defense is to be over 1km inland or 100ft above sea level.
In many (not all) places you would have time to do either of these. You also have the option of quickly heading out to sea as the Tsunami only has effects at shallow depths (right by the coastline). So, an additional 20 min could indeed save a huge number of lives.
I would also add, that you might not be safe even 1km inland if you were withing a natural "funnel" like a trianglar river delta with highlands on each side...
Try to hack my 31337 firewall!
The article is interesting in the use of GPS recievers to gather information. Let's look at two datasets.
From Wikipedia: "The accuracy of the GPS signal itself is about 5 meters (16 ft) as of 2005 and has steadily improved over the last 15 years. Using differential GPS and other error-correcting techniques, the accuracy can be improved to about 1 cm (.4 in) over short distances."
From NASA: "Large earthquakes often cause permanent movement of the Earth's surface, a result of the motion that occurs deep underground. The tsunamis spawned by the magnitude 9.0 earthquake on December 26, 2004, were the result of motions of the sea floor above the earthquake fault. Seismic measurements and computer models show that the Burma Plate slipped up to 20 meters (66 feet) at the location of the earthquake, 18 kilometers underground. The sea floor above moved less, up to 5 meters (16 feet) vertically and 11 meters (36 feet) horizontally."
So, the practical uses of this, even without error-correction, are theoretically viable for creating an early warning system for Tsunamis.
The article states that it should only really take 70 seconds for "a good idea of the final deformation". Linking this data to website and government run servers, the early warning system for Tsunamis would be far greater and accurate that say, tornado early warning systems. Consider the following exerpt from PBS's NewsHour: Developing a Global Tsunami Warning System: "STUART WEINSTEIN, Geophysicist, Pacific Tsunami Warning Center: I think the 'holy cow' moment didn't occur until we started getting the first preliminary reports over the wire services that, in fact, a damaging wave struck Phuket, Thailand and Sri Lanka.
BETTY ANN BOWSER: Were you frustrated?
Stuart WeinsteinSTUART WEINSTEIN: Very frustrated. Frustrated and to a certain extent humiliated. It's humiliating for me as a geophysicist working for a tsunami-warning program to learn first of a tsunami from a wire service than from a tide gauge. That -- it doesn't get any worse than that, quite frankly.
BETTY ANN BOWSER: Thousands of miles away at NOAA's Pacific Marine Research Lab in Seattle, tsunami researcher Vasily Titov was also frustrated. It took him until 4 a.m. in the morning of the next day to run this computer model, because he didn't have tsunami readings either."
Considering the earthquake hit at 00:59 GMT, and the wave first makes landfall at Sumatra 01:30 GMT, then 02:30 GMT in Thailand, then 03:00GMT in Sri Lanka and India... having a result from this system at 01:00GMT (70 seconds) automatically piped to the national emergency centers of governments, could have at least mobilized aid faster in Sumatra, and could have evacuated thousands in Thailand, Sri Lanka, and India.
A total of approximately 275,000 died in the Indian Ocean Tsunami of 2004. At a cost of even $10,000 per detector, 5000 detectors for $50million USD would have only cost $181 for every person that died.
I8-D
No, you have 20 minutes to:
THEN you can drive. If you're not busy blogging the event, telling the other blogophiles you'll be AFK for a while.
When they came for the communists, I said "He's next door. Take him away. Goddam commies."
Check out the Southern California Integrated GPS Network for an example of highly accurate (sub millimeter) uses of GPS over a large area. The receivers being used in this network are 10 years old and still returning excellent data which we can use to compute annual tectonic plate motion. In 1999, after the Hector mine earthquake, we were able to determine 17cm of slip at a sight 40km away from the epicenter. This was done in a few hours.
Also, take a look at the Plate Boundary Observatory which is being built now.
--Keith