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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...
MoM++ - A Classic Expanded - [Master of Magic 1.5]
http://mompp.sourceforge.net/
I don't see what GPS receivers can do here that accelerometers can't.
Warning: this article may contain humor, sarcasm, parody, and perhaps even irony. Read at your own risk.
Knowing the accuracy of GPS at the best of times of the time it takes for a usable signal to be picked up, it seems that they don't seem rugged enough to actually be of use to geophysicists for a reasonable amount of time.
However, anything that can be done is always a good thing, of which I'm sure everyone will agree with.
But looks like there may be a way to detect a tsunami caused by an under sea event;
Sounds promising but is it possible to tell the difference between air movement caused by a tsunami and just a sudden gust of wind? How dense would the sensor array need to be to prevent false positives?
Does anyone have any further information regarding what grade of GPS is being used? Based on the price point, I would have to guess that it is Mapping grade GPS equipment, but the problem would be that in order for Mapping grade GPS to update, the person (or mount) holding it, must be moving to get the corrections from the satellite. Survey grade may work, but it wouldn't be under $10k per receiver.
Any help?
for GPS devices on the ground, I doubt they'll do much good for earthquakes that happen deep on the ocean floor; and those seem to be the ones that generate the most powerful tsunami.
Still, cheaply covering part of the risk is definitely worth it.
Traditionally, the AGU meets in San Francisco in the early part of December, in between the end of classes at the Universities and the start of the Holiday rush.
If it weren't for deadlines, nothing would be late.
"I don't see what GPS receivers can do here that accelerometers can't."
Cost more.
Sorry, posted too quickly. Some colleagues went to the meeting, and I just remembered they were back from it all last week.
If it weren't for deadlines, nothing would be late.
But this is just ridiculous. I mean honestly, when was the last tsunami before this recent event? Does anyone honestly think their tiny human little heads will be perking up 2000 years later just as vividly, watching the GPS screens, when the next tsunami comes? Seriously, give it a break. There was nothing we could have done. And perhaps in the future we will be able to do something beforehand. But that's not worth reporting, because I'll bet you my two arms and three balls that we won't have a tsunami in the next 100 years. This is just another tiny scientific advancement which isn't really worthy of taking up our time, because we're not going to ever see it in use, and we're not going to care.
From TFA:
k .html
s sen_etal2002c.pdf
"With GPS, the displacements are measured second by second," said Bock, who also presented at the American Geophysical Union conference. "Within 70 seconds you have a good idea of the final deformation." In addition to predicting tsunamis, he thinks GPS modules could be used to monitor the activity of volcanoes and landslides in real time. [emphasis mine]
I thought GPS was already used extensively in volcano studies.
http://vulcan.wr.usgs.gov/Monitoring/GPS/framewor
No specific mention of real time data whacking in that link? A quick Google, and we find this, for example:
http://www.gmat.unsw.edu.au/snap/publications/jan
Computational Chemistry products and services.
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
You would think that projects like this, with such potentially positive results for every country with a coastline, would be a real focal point for government spending. Unfortunately, it seems like too many governments only find money for these things after the fact, when TV screens start showing the after-effects of catastrophes. As much as I believe that a global early warning network is a good idea, I am pessimistic about it ever being completely implemented, for reasons of bureaucracy and cost.
NeverEndingBillboard.com
NeverEndingBillboard.com
(and posting as AC, so I'm not karma whoring, Jeebus)
GPS Could Speed Tsunami Warnings
By Elizabeth Svoboda
GPS satellite receivers are already navigational must-haves for hikers and drivers. Now scientists are hatching plans to press them into service as tsunami predictors.
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.
Unlike seismometers, GPS receivers can measure the movement of the ground in real time. Because quake magnitude is a direct function of how much the earth shifts, Freymueller has demonstrated that the receivers can obtain precise measurements of a massive quake's severity in as little as 20 minutes.
"Seismometers measure the velocity of the ground, and you have to collect a number of cycles of the important wave in order to get that measurement," he said. "GPS receivers measure the static displacement of the earth, and after the first few minutes of a quake, that doesn't change much."
Freymueller envisions a new tsunami-warning strategy that would use seismic and GPS data in tandem to calculate a wave-causing quake's strength soon after its onset. This would enable more-accurate computer simulations of the coming wave, allowing more-targeted evacuation strategies. Planting the receivers every hundred miles in tsunami-prone areas, he added, could be done in a matter of months, and each receiver would cost less than $10,000.
"Early warnings from GPS could save thousands of lives," he said. "In last year's Indian Ocean tsunami, there were potentially one to two hours for evacuation, had an accurate warning system been in place. Every minute counts."
Seismic measurements of very large quakes like the one that caused last year's Indian Ocean tsunami take several hours to fine-tune, because the moving vibrations must be recorded at a variety of stations in different locations. When the quake that caused the giant Southeast Asian wave first hit, scientists at the PTWC estimated its magnitude at 8.0, but revised their estimate to 8.5 an hour later. After a few more hours passed, a team at Harvard University pegged the quake at 8.9. The final reading, 9.2, was not agreed upon until months afterward.
Yehuda Bock, a geologist at the Scripps Institution of Oceanography, has also investigated the possibilities of using GPS receivers in tsunami-warning systems. His results are similar to Freymueller's, indicating the receivers can gauge the ground movements created by tsunami-causing quakes with unprecedented precision and speed.
"With GPS, the displacements are measured second by second," said Bock, who also presented at the American Geophysical Union conference. "Within 70 seconds you have a good idea of the final deformation." In addition to predicting tsunamis, he thinks GPS modules could be used to monitor the activity of volcanoes and landslides in real time.
Like Freymueller and Bock, Peter MacDoran, a GPS expert who works for George Washington University and Taco Bell's Space and Advanced Communications Research Institute, wants to make GPS receivers part of disaster-prediction networks. But he foresees using them in a different way: to track the movement of tsunami-associated pressure waves in the Earth's atmosphere.
"Quakes that cause tsunamis create deformation on the surface of the water, and that causes an atmospheric 'thump,'" MacDoran said. "A compression wave travels into the upper atmosphere, and that disturbance causes subtle changes in the way GPS signals travel." Digital processing of the changed signals coming from nearby receivers
"In 23 minutes and 12 seconds a tsunami of height 13.6 meters will hit blah blah blah...".
Actually it is the core idea.
Tsunamis not caused by weather. They are generally sparked off by earthquakes, which we cannot predict reliably. However, once one is sparked off and we know the nature of the event(what kind of earthquake, magnitude, location) we can predict the tsunami once we crunch the numbers. However, this takes time.
Tsunamis are basically shock waves. They travel at 500-1000 kilometers an hour while in the deep ocean. That means that you are going to have much less than an hour in most situations. If you're talking over an hour of travel time you're talking about a minor tsunami for anything less than a huge asteroid hit. Near shore it slows down to 'dozens of kilometers' as it builds into a huge wave.
Seconds count in this situation. We're talking sirens annoncing the need to take immediate shelter, or travel inland/out to ocean. The most dangerous area is the coast region. If you're far enough out to sea, the wave can be handled, if you even notice it. Coastal mega-hotels need to be built strong enough to take the wave, though I'd see evacuating all of the ocean side and lower level rooms.
20 minutes can save a huge number of lives, though. A moderatly healthy person should be able to walk at least a mile and a half in that time. It's also the sort of situation where you're likely better off walking than trying to take your car. So many other people will be trying to drive, panicing, that accidents and traffic will slow you to a stop.
I don't read AC A human right
Until the tsunamis get ahold of these.
Word of impending doom spreads like wildfire... people would find out relatively quickly, I think everyone simultaneously trying to leave an area at the same time might cause a lot of problems actualling leaving...
So you'd wind up drowning in your car...
===
However, there is always the chance you could be one of those first few to make it out... you never know!
MoM++ - A Classic Expanded - [Master of Magic 1.5]
http://mompp.sourceforge.net/
I think this article (and the researcher) missed the point of a far more profound, yet more far-off, use of GPS in earthquake detection. Spectrum recently ran a story describing how the GPS system among other things could sense impending earthquakes days, weeks, and even months in advance of an earthquake. The basic concept is the cracking of rocks in the crust leading up to an earthquake frees electrons which rush downward creating positvely charged holes. These holes also appear at Earth's surface and attract electons out of the ionosphere. The phase difference of the two signals the GPS satelites transmit is affected by this change and the change from normal values can be detected. This is still a long way off, and the use of GPS to measure this phenomena is only one and definitely not the best. But it sounds better than the couple hours mentioned in the article.
The devices being used for this work are typically $10K+ units using RTK, as opposed to general purpose GPS (like the Garmins etc you might use for hiking). They also use very good antennas which provide good coverage. RTK receivers can measure down to 20mm (yes less than 1 inch) and can thus provide measurements of flexing and slumping and thus things like the tsunami energy and stresses that often signal pending earthquakes or volcanic activity. GPS has a long history (many years) in monitoring fault lines etc in places like California, Japan and New Zealand. These units are perminantly mounted at monitoring stations, so aquisition time is a non-issue.
Engineering is the art of compromise.
Just wanted to add that these GPS measurement stations put up for this purpose could give valauable information that could also be used for other many purposes, I can mostly think of geophysics purposes as that is what I work with myself, but I imagine such a web could be used for many other things
I remember a paper about the isostatic rebound after the icecap in Scandinavia where GPS recievers were used. A curiosity I remember from the paper was that at the coastal areas there were quite a lot more uncertainty on the vertical movement, which the authors said probably was caused by the bigger amount of snow that assembles on the GPS devices and thereby causing refraction of the waves used for the GPS measurement
GPS information could is also used to determine the absolute movement of plates and I imagine that this system could also with time, be used to predict big earthquakes more precisely and thereby give even more time to prepare for the tsunamies etc.
GPS is easier to say than acceler-o-whatsit is.
Here is the Alaska/Pacific tsunami detection data from NOAA: http://www.ndbc.noaa.gov/dart.shtml
Interesting stuff.
TFA didn't mention this, but they may be talking about Geodetic GPS receivers. These units are often used to measure plate drift and can measure down to 5 millimeters or so. Something like http://www.trimble.com/5800.shtml
A team was on Unimak over the summer to install a few stations which can measure submillimeter movements (as I understand from what they told me); these are GPS-based but there may be other stuff involved for all I know. The site selection was not at all a trivial operation, involving three specialists in different fields as well as a lot of helicopter time. I guess it's tough to find good solid bedrock in a volcanic area.
They use a laser system to transmit the data from the mountain to the town's satellite link, uploading the data stream in realtime. Very cool stuff.
If this GPS idea works as advertised, it'll be a very useful incremental improvment to the tsunami warning networks. But it'll hardly be revolutionary. Being able to determine which events will produce a tsunami just from the seismic data - that would be revolutionary.
http://www.germany-info.org/relaunch/business/new/ bus_tsunami_buoy_8_2005.html
That's funny ... I thought it was two weeks ago.
Build it, and they will come^Hplain.
It would seem like a better idea to have a sort of public-safety warning system integrated with the mobile phone network. This way, the authorities could simply send SMS messages (or even graphic messages) to people within a specific geographical area, giving them the nature of the incident in question.
I think we had something like this that put messsages on your radar detector, but it died in the womb a while back.
This would work for virtually everything - if a train derailed and spilled hazardous chemicals, the fire department could use the public safety system to get people out of their houses. If a hurricane was going, they could use the system to coordinate evacuation so that people wouldn't get trapped in giant traffic jams. And if an escaped killer got out of jail, they could send everyone in the immediate area his picture.
Another way GPS receivers can be used is by placing one on a buoy a few miles off of the coast. When a tsunami passes the buoy, there will be an unusually long-period wave detected by the software monitoring the buoy's position. When this occures shortly after an earthquake a tsunami warning would be issued to the coast, giving the residents 5-10 minutes to head to higher ground. See this page for an example installation. This usage of GPS receivers has been around for at least 5 years.
about how they would use GPSr's to measure *seafloor* movement. Is this thing submerged and anchored to the floor of the ocean? Or is it a buoy with an umbilical to something fixxed to the seafloor? Or is it a buoy that simply floats and measures at the surface only?
I'm sure they have considered it, but I don't see it in the article.
They should be using Inertial Navigation Systems. And Wired should fix it's registration process.
Okay, point taken ;-) I was trying to correct a minor inaccuracy in TFA and ended up flubbing it in a couple of ways. :-|
... as in right after classes end at most universities. If you're really concerned about meeting dates, you can always check out the AGU website.
Generally the AGU meets as early as possible in December
If it weren't for deadlines, nothing would be late.