Slashdot Mirror
GPS Used To Monitor Continental Drift
metz2000 writes "BBC News is reporting that a team of scientists from Nottingham (UK) are using GPS to measure sea levels and continental drift. The team has around 50 stations across the UK, and use GPS technology to track miniscule changes in altitude and location. This allows the team to gain an understanding of how the UK landmass is likely to change over the coming centuries. They have discovered that the British Isles are tilting, with the north of the country gaining altitude and the south of the country 'sinking'."
well this should sort the north/south divide and tilt (apollogies for pun) the house price difference to the north.....
just my 2 (euro) cents worth
Alex
Considering a lot of GPS receivers have an error of + or - 10 feet or so, I wonder if they are using very precise equipment, or if having the redundancy of many units makes up for the rough estimates GPS satelites give.
http://almostsmart.com
...you tell me this *after* I've just bought a house in Southampton. Bummer. I knew the must be *one* good reason to live in Scotland...
Nick...
I didn't realize that GPS was accurate enough for that...
I think i heard once that there were two types of recievers, one was more error prone, but gave you an updated location every second, the second was very, very accurate, but took over 10 minutes to get a position fix.
can anyone clue me in here?
No, unless the fat guy is running really slow and you have a strange kind of earthquakes in your part of the world....
They are measuring slow changes, not quick seismic vibrations.
Jeroen
Secure messaging: http://quickmsg.vreeken.net/
I think you can extrapolate this data into a correlation with population. Look at the warnings from the 1970s about halting population growth in California, especially west of the San Andreas Faultline. There were no changes, and then an earthquake strikes.
Now the most populated area of the UK is sinking and the rest rising. If you think about it, it is quite logical. The weight of london alone is billions upon billions of tonnes, the building and auto infrastructure, not to mention several million people.
We are having a much greater effect on the planet than anyone could know.
RST
Lifing at one and and sinking at the other? Where have I heard this before?
Oh yeah, that's right... the Titanic...
Sounds to me like this tilting is just the land settling down after the last ice age. The north of the country used to be covered in ice, while the south was clear. Now that the weight of the ice has gone, the land is just seeking a point of equilibrium.
1/6 Acre house plot, on an island in the north-west of Scotland, in an area that is (hopefully) getting wireless broadband within the next year.
If you can sort out immigration, USians can apply too - avoid your Iron Curtain before it's too late.
I may just be being stupid, but since you have the altometer on a boat isnt it always at sea level..... and thus less than useful?!
just my 2 (euro) cents worth
Alex
The fact that the northern part of Europe is rising and the southern part is sinking (for a rather broad definition of southern: Holland is sinking too), has been known for a long time. I was told in highschool (think before 1983) that this is due do the northern part having been pushed downwards during ice age(s) due to the massive weight ot the ice. When the ice last retreated, the current tilting movement was initiated.
Linux user since early January 1992.
Slightly OT, but just to mention that imaging microwave radar (as those mounted in the ENVISAT or ERS satellites, for example) is also being used to monitor small changes in elevation, using a technique based on interferometric SAR (which is behind the Shuttle Radar Topography Mission.
The benefit of using a satellite orbiting around the Earth is that you don't need to deploy all the "base stations". If you want to find out more, google for "differential interferometry" or somesuch :-)
This allows the team to gain an understanding of how the UK landmass is likely to change over the coming centuries.
So, is the UK drifting west across the Atlantic, as some of paranoid us Brits fear?
And if they relocate people to the north, will it stop the process?
the first thing i thought of was a piece in wired about microsatellites to track terrestrial phenomenon. the real world, that outside of the military, has plenty of uses for new technology as soon as its readily available and not too expensive. there was another article in wired about using satellite technology to track trucks. both of these applications use space technology, and neither of them can be replaced simply with gps, but they illustrate the types of applications that such technology enables. anything that requires precise geographical measurements over time is now possible, as long as you can get a grant for the equipment.
...vividly encapsulates that post-Watergate/pre-punk/coked-up moment when you could trust no one, least of all yourself.
this brings a whole new meaning to:
... or was it 'waves'?
"Rule, Britannia, Britannia rules the sea!"
Global warming! Phew, it's hot!
Global freeezing! Brrr, it's cold!
Recreational boating decreases the sea level!
etc.
These devices are not accurate enough for this. Continental drift occurs on the order of feet per eon. I can almost hear the hysteria: "Researchers predict the Atlantic Ocean will be empty by 2012", soon to be followed by "Oops, disregard that last report - Mount Kilamanjaro will be an island in 2015!"
What a waste of time.
Curb CO2 emissions: Kill yourself today!
..in how they use GPS to make such precise measurements you can read about it here:
Using GPS to Separate Crustal Movements and Sea Level Changes at Tide Gauges in the UK
Application of the Dual-GPS Concept to Monitoring Vertical Land Movements at Tide Gauges
Whenever the offence inspires less horror than the punishment, the rigour of penal law is obliged to give way...
From "Navigation Satellites & GPS v2.2.3 / 01 dec 02 / gvgoebel@earthlink.net /"
Geophysicists have been exploiting GPS since the mid-1980s, using it to measure continental drift and the movement of the Earth's surface in geologically active regions. They have been able to obtain accurate surface measurements to within a few millimeters through a procedure known as "carrier tracking", which is even more accurate than differential GPS. Carrier tracking actually senses the phase of the carrier signals on which the location code sequences are broadcast. It is, not surprisingly, a tricky and subtle procedure, and not applicable for general use.
Ok, i understand the basic idea behind GPS. Satalites in orbit where basic geometry is used based on the subtle diffrence in the time it takes a signal to get to a device, well i'm assuming this.
Could be useful for tracking moving things like land masses and ocean levels.
Question: If our land masses are moving, and water moves, what ever do we actually calibrate the satalights with in the first place?
The only thing that comes to mind is the axis of the earth. Would someone wiser then I in this area elaberate, i'm somewhat curious.
There is no sanctuary. There is no sanctuary. SHUT UP! There is no shut up. There is no shut up.
There are more clues to one's altitude than to one's latitude and longitude...you see where sea level is, or see signs denoting altitude as you travel. These are in the same units your GPS displays, and you can compare them and notice the error. If you had access to the same sort of easily interpreted errors in the horizontal plane, you would notice the errors there much more than you do now.
Its been known for a long time that the north is rising and the south sinking. We were taught that in Geography about 7 or 8 years ago.
Its due to the glaciers having melted in the north.
.. I thought it couldn't sink any further. :)
I always new there was something fishy in the south side of britain. Ah well.. atleast now they have showed that it will hit rock bottom soon
Whats the point of having excellent karma if not to spend it every once in a while?
Well that's all very well for you, but London is always "down" for me since I live in Edinburgh.
It's a pity we couldn't speed this thing up a bit so I could see house prices changing within my lifetime.
Dunk
The "tilting" is just an observation of the variying stretch of an equatorial bulge, due to centrifugal force. Also, the rotational axis wobbles between 21.5 and 24.5 degrees and the GPS precision varies slightly due to moment of inertia.
Scientists from Nottingham... Not quite.
Your hand-help GPS reports a fix once a second or so -- so the integration time of the GPS data is approx one second.
If you program your GPS receiver to integrate GPS data over, say 24 hours instead of one second, then you get very high accuracy. Your GPS has to remain perfectly stationary during the integration.
Hand helds don't have an option for setting integration time. You need fancy, expensive receivers for that. Or, you can roll your own, which isn't as hard as it sounds.
In the course of every project, it will become necessary to shoot the scientists and begin production.
"They have discovered that the British Isles are tilting, with the north of the country gaining altitude and the south of the country 'sinking'"
GREAT DISCOVERY *sarcasm*
Since the late pleistocene the big icesheets on top of Northern Europe disappeared by global climat change from glacial to interglacial (cfr. Iversen model). As a concequence of this loss of mass on top of these plates they began to bounce back up. Imagine taking a piece of drifting wood, push it down. If you lift your finger it will rise up again. The same principal goes for continental plates and is called isostatic uplift.
So, since the beginning of the holocene and end of the pleistocene countries now known as Sweden, Norway began to rise and Belgium and the Netherlands for example began to sink, because the y once were uplifted by the weight on the northern part of europe.
It seems normal that these consequences aren't just limited to european main land but also influence the UK. In fact Scotland has had a big icecap during the last iceage so the isostatic uplift of Scotland and the drowning, if you may call it that, of the south of the UK isn't exactly new.
They may claim having measured it, but they certainly may not claim the discovery of these changes because that's veeeeeery old news.
Who moderated this as Interesting? Please connect brain before moderating. Moderating as Funny I can maybe accept, but Interesting?
The stuff humans account for is miniscule compared to everything else. Think of it in terms of height; human constructions are is in the range of tens of meters, not particularly dense and quite spread out, while the ground below consists of kilometers of rock. It will make no difference whatsoever, at least not by pure weight. Erosion and other effects could be significant.
This post is free (as in cheese in a mousetrap).
In the medium term, the greater risk seems to be from rising groundwater, presumably resulting in London floating off down the Thames.
GPS accuracy is somewhat consistent among manufacturers, and is generally more accurate the more you pay for the equipment. However, there is always a margin for error. For example, Wilson's GPS Accuracy page states that vertical accuracy depends on "latitude (errors for vertical accuracy rapidly increase with latitudes greater than 65 degrees), receiver/antenna, local geometry/multipath and satellite geometry (VDOP)"
The real question is are the Nottingham group using high grade and control tested equipment and have they properly accounted for discrepency. Stating that Scotland is rising two millimeters a year is quite the claim.
I'm wrong and so are you.
Tilting up in the north and down in south won't change this. If it had been the other way around though..
Unless of course you think that going north on a map is going down for some reason.
To quote the Kopyright Liberation Front (The Justified Ancients of Mu Mu):
Bolton, Barnsley, Nelson, Colne, Burnley Bradford, Buxton, Crewe, Warrington, Widnes, Wigan, Leeds, Northwich, Nantwich, Knutsford, Hull, Sale, Salford, Southport, Leigh, Derby, Kearsley Keighley Maghull, Harrogate, Huddersfield, Oldham, Lancs, Grimsby, Glossop, Hebden Bridge, It's Gay Up North
How small a thought it takes to fill a whole life
Sweet maybe in a few millenia we will be able to drive right across to France for that cheap booze and cigarettes.
-- Karma Karma Karma Karma, Karma Chameleon - Boy George
The world is a close aproximation of a sphere, hence it all depends where you take your plane of reference to lie.
If you take your plane of reference to run through London, everything is down from it.
..some scientists studying the "sinking" effect have noted CowboyNeal's recent move to Southampton.
My journal has hot
What us English need is an ingenious businessman to come up with a plan to turn the Country around, then we just start building in the 'new south' and it evens everything out.
"Dre don't get as high as me.... I'm Cheech and Chong" - Snoop Dogg
Altitude is usually measured in height above mean sea level. Unfortunately mean sea level depends on many things including local gravitational anomalies. A big dense rock underground will make the gravitational field locally stronger which means that even if the surface above the rock is mathematically flat, it will appear to have a dip in it where the rock is.
For a GPS to give accurate absolute altitude, it needs to have a map of all the local gravitational anomalies on the planet (or at least in the area it is used in).
OTOH if you are trying to measure changes of height ("Scotland is rising") the absolute zero doesn't matter.
All I want is a secure system where it's easy to do anything I want. Is that too much to ask ~~ Randall Munroe
The tilt, at least, has been known for a quite a while; I remember joking with a friend from London that London might be horrible, but if we just waited a few million years the problem would be solved (we were in Scotland). That was back in the late eighties.
yeah, it seems to be stuck on 0 all the time.
(yeah, yeah, I know water is not always at sea level, it's a joke)
"Son, in a sporting event, it's not whether you win or lose, it's how drunk you get" - Homer J. Simpson
The problem will actually accelerate exponentially, since the south is over populated already and this news will only add to it.
Just make sure you live near the coast so you can flip to the other side when that happens.
First, pardon all typos and mispellings -- its 7am and Im about to go to my second to last environmental geology classes. Its a presession class that goes for 9 days, 8a-12:30.
...
Anyways, we covered plate tectonics and this movement stuff and its very interesting.
If you need some kind of science class and you had your chem and phys in highschool and want to try something different, your university probably offers environmental geology and its an absolutely amazing class. Ive had a really easy time with it and learned quite a bit in the last 7 days.
The part about drift that I had never heard before was that pangea was not the first super continent and these plates move damn fast. eventually a new super continent will be formed just like the 4-5? that came before.
Also, those cool hotspots (Hawaii, Iceland, Yellowstone, and more) are going to be the key to geting a nuclear bomb to the earth's core if it ever stops moving
The ultimate network admin tool needs HELP!
This is hardly news, I was taught about this 10 years ago at school.
I was taught (only a couple of decades ago, honest!) that this sort of rebound after the ice age was supposed to be going on - in fact it was (if I remember correctly) one of the justifications for the Thames flood barrier. However, no-one (at school anyway) ever let on how this rebound was measured. It's nice to know that modern technology allows for easier monitoring of this sort of measurement. That said, does anyone know whether measurements of this sort had been done before and if so, what were the techniques?
Cheers,
Toby Haynes
Anything I post is strictly my own thoughts and doesn't necessarily have anything to do with the opinions of IBM.
No! The tradition is that regardless of your location within the UK you always travel "up" to the capital city of London. I live much further north than Edinburgh, and therefore by sheer geography alone, I, quite simply, must know what I am talking about. And before we get into an argument about national identity, I don't agree with it either but that is the tradition.
As for house prices, Edinburgh has gone through an explosive increase in the past few years, mostly due to the Scottish Parliament. You must have bought a house in the past 2-3 years, in which case it will be some time before you see a return on your investement.
GPS measurements have also allowed scientists to show that the UK is drifting about 2-3 cm each year in a north-easterly direction.
I disagree. The UK is only drifting north. Since we have no east or west pole, the east-west component of the velocity can only be stated relative to some other plate. We could just as well assert that the UK is stationary in the east-west direction, and the other plate is moving west.
Your time-scales are all wrong. Nothing geologically significant (except earthquakes, volcanoes, and meteor strikes, and even then...) happens in a century time scale. You'd need to think in 10's of thousands of years at a minimum.
Some people are slow, and have to be reminded often...
Wow, and the Queen thought she'd had an "annus horribilis" a few years ago!!
OK, now what?
This was already common enough knowledge for those interested in the subject ... the south east & east anglia are sinking, the north west rising.
The sky is falling! The sky is falling!!!
:)
Oh--wait--the ground is rising...
umm--nevermind
This seems like very old news to me.
I seem to recall being told this in the early 1980s at school.
Apperently it's the "rebound" effect. In the last ice age all the ice caused Scotland and Northern England to sink under it's weight.
Since it all melted it's been slowly rising.
I can't remember why southern England is sinking though. Maybe there's a pivet somewhere through Shefield or something ?
One way to improve accuracy is to integrate thousands of measurements made over several hours. Then measure over a network of stations to reduce error. Also there are stricks like using the carrier signal for further precision.
I remember an in-depth discussion of the tilting effect on the Open University in the late '80s.
Geologists have been measuring micro-motions of the earth since GPS started in the early 1990s. There are thousands of talks on the subject here .
I have lived north of London all of my nearly 24 years with the exception of eight months and can say quite certainly that I have never heard anybody talk about travelling "up" to London.
:)
That aside, I was really just looking for an excuse to post a useless comment on the lines of:
Wahoo! This is the closest slashdot story to me ever. I walk past the University of Nottingham IESSG building every day to get my lunch.
Yeah, I'm sad. Please don't mod me down for it though
Cheers,
Roger
Do you have any better hostages?
Cheers,
Ethelred
Everyone wants to be Ethelred. Even I want to be Ethelred.
Heresy! The earth is obviously flat.
I have seen the English terms "ice sheet" and "continental glacier" for this.
SIGBUS @ NO-07.308
That isn't continental drift. It is selective availibility!
Do you like German cars?
GPS has just confirmed that we have, in fact, collided with France. More at 11, after our continuing coverage of the war between Linuxia and Microsoftistan.
Misquote: It's Gay Up North
Nay lad, that's It's Grim Up North.
Anyroad. Nowt wrong wi' t'south sinkin'. Get drownded, thee southern bastards!
"Information wants to be paid"
They didn't discover this. The fact that the north is rising and the south sinking has been known for quite some time-- certainly longer than the GPS constellation has been up. I have a book here somewhere (can't find anything here!) that was written in the late sixties that mentions it as established fact, then positing the theory that ice age glaciers "pushed down" the island and it's "springing back". It shows a picture of some 400+ year old castle in the north that was originally built with its moat-gates open to the ocean but is now some 100 feet above sea level! Doesn't take GPS to tell you the island is tilting.
If a job's not worth doing, it's not worth doing right.
they can hoist a giant sail from the center of the isle and commence to steer! Let's park it in the Mediterranean for a while! :-D
j/k, of course...
The UK has asked anyone over 90kg to move to the north. Starting Nov 1, any 90+kg person found in the south will be fined.
20 Euro to be paid to fat people who move north.
A free trampoline will be issued to the relocated to help with the tilt.
Why worry? Each of us is wearing an unlicensed "nucular" accelerator on his back.
Sig changed for readability by G.W.
There is a group here at the USGS Pasadena Office that is doing this. You can read about the project at http://www.scign.org
Most geological surveyers can use gps equipment with post processing of data allowing you to find your location within a millimeter or two. Its pretty common within the US as well. Look at http://cors.ngs.noaa.gov to find other projects going on in the US. They are also using GPS to watch the Gulf coast sink. Your little hand held GPS receivers are limited to wide error because of processing power and the type of GPS signal they use.
Wasn't it like 3 feet and then improved to 1 feet? I doubt that even if they have 1cm precision, this won't be precise enough for them..?
-- Leeeter than leet
FWIW, they've been doing this sort of thing in western Canada since 1991.
t m
www.pgc.nrcan.gc.ca/geodyn/docs/wcda_bc/content.h
My first real programming job was at the Pacific Geoscience center (a decade ago), maintining the unix programs and scripts that downloaded seismic data from these remote GPS stations.
Slashdot: come for the pedantry, stay for the condescension.
They have discovered that the British Isles are tilting, with the north of the country gaining altitude and the south of the country 'sinking'
That explains the difference in house prices up North and down South. I wonder when they'll start advertising southern homes as "temporary accomodation"? :o)
Resistance is futile. Reactance buggers it up.
They have discovered that the British Isles are tilting, with the north of the country gaining altitude and the south of the country 'sinking'
Well of course the South of the country is sinking. It's densly populated. More people mean more houses, more cars, more infrastructure, more tea shops, more cake shops selling sweet meats and pleasant fancies . . . . which all lead to more weight. It's what many non-scientists call "the see-saw effect".
Does this also mean Scotland's Highlands will be gaining altittude, and we'll have to change all maps and road signs to say "Higherlands"?
~~~~~~~~~ "I must create my own system, or be enslav'd by another man's." William Blake, Jerusalem.
I'm sure people would like to know that the use of GPS for geodesy has been going on for many years.
The way that it is done is not to use the same sort of measurement used by handheld GPS receivers but to use the phase of the signal coming from the satellite.
If you monitor the gps network for a long enough period using these techniques you can get down to the millimetre level of accuracy horizontally. The longer you monitor the better the accuracy you can get.
A group working here, at Oxford University, has been doing such work in Greece and the South Island of New Zealand and is now part of a national centre of excellence, called COMET.
This page should give you a better idea about what they're doing.
Agrajag: "Oh no, not again!"
They have discovered that the British Isles are tilting, with the north of the country gaining altitude and the south of the country 'sinking'.
Either that, or the GPS satellite positions are tilting!
I was wondering how long it would talk for someone to mention NGS and CORS (I work for NGS)
As a continent, I find this to be a grave violation of my privacy. Can I at least opt out of this tracking?
"People that quote themselves in their signatures bother me" - athakur999
I thought I would include some links to similar projects:
SCIGN -- Southern California Integrated GPS Network
http://www.scign.org/
This GPS array has 250 active stations throughout SoCal continuously monitoring crustal deformation. SCIGN was started after the 1994 Northridge Earthquake and has helped the determination of the velocity field in Southern California produced by SCEC.
An interactive map of station locations can be found at:
http://pasadena.wr.usgs.gov/scign/Analysis/
SCEC -- Southern California Earthquake Center
http://www.scec.org
This is the umbrella organization for EQ research in Southern California and is the parent organization of SCIGN.
PBO/Earthscope -- Plate Boundary Observatory
http://www.unavco.org
One of the most exciting new developments in GPS. Recently the US Congress approved the Earthscope initiative which includes 3 separate parts. The GPS portion is the PBO which will include 875 new stations from the Mexican border through Washington and Alaska. This massive array will be built over the next 5 years.
There are also several other regional deformation arrays include the Basin Range network, The Bary Area network, and a cluster of sites around Parkfield, CA.
Equipment:
The GPS equipment used at these sites are commercially available dual frequency geodetic quality receivers which can recover the military code without needing the military keys. The receivers are capable of good precision when operated alone and are capable of sub-millimeter precision when used in a continuously operating network.
This type of processing requires extremely accurate satellite orbits provided by the International GPS Service (http://igscb.jpl.nasa.gov/).
These large GPS arrays have been deployed throughout the world where there is a seismic hazard. Japan is one of the predominant countries with large GPS networks in place.
We encourage you to look at the various websites and learn about these projects and the science that they produce.
--Keith
SCIGN Network Coordinator
Lex Luthor, eat your heart out.
Friends don't help friends install M$ junk.
I was writing my senior thesis on using GPS to track land movements way back in 1994-95. This is not news. My paper was about tracking seismic buildup in the New Madrid Seismic Zone.
Hyperic Community Manager
On further investigation scientists have discovered that the tilting and sinking of the British isles is directly related to the movements of John Prescott.
,and he sprung first to mind.. I'm sure with a bit of thought I could've found someone funnier/more suitable, but this is /., since when have posters ever applied thought? :P)
An attempt was made to request that Mr Prescott go on a diet, but unfortunately the delegate picked to make the request was never seen again, presumed eaten. Scientists are now designing a special protective suit, and hope to make another attempt early next year.
(note, nothing against John P personally, I just needed an unpleasant fat person
Curiosity was framed. Ignorance killed the cat.
Here's the link to the Southern California version of GPS monitoring (Southern California Integrated GPS Network -- SCIGN). It's run by the Southern California Earthquake Center and used to predict where earthquakes have high probabilities of occurring.
http://www.scign.org/
The problem is all the people and property being dragged to the south portion of England. They need to move a few large cities to the north end to balance things out better. ;-}
Well that's all very well for you, but London is always "down" for me since I live in Edinburgh.
Except you're making a very common mistake.
Not really your fault though. All the mapmakers and such get it wrong as well.
They always show the planet upside down. I mean look at it. The vast majority of the landmass at the top?!? That's just crazy. It obviously would have slid down to the bottom by now.
Now to combine our 2 favorite /. poll answers:
CowboyNeal is fat you insensitive clod...
At the next eco-hypocrisy-meeting, count the private jets used to get to the meeting. Should be interesting to see that
Accurate information actually modded up on slashdot. Film at eleven.