Talk:Ground-penetrating radar

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Question:

Can GPR be used effectively to locate buried facitlites such as buried pipes (4" to say 12"), or buried electrical cable with any kind of confidence? —Preceding unsigned comment added by 207.229.13.65 (talk) 20:32, 19 March 2008 (UTC)

Contents

[edit] Question

I want to know atmosphere effect on gpr radars

What do you mean by the atmospheric effect? The radar pulses are sent into the ground. However, if the transmitter antenna is not shielded it emits radiation everywhere. Thus, nearby buildings and trees also cause reflections that may be seen in the measured data. Is this what you mean or am I missing something?
Most GPRs have an antenna in contact with the ground. No atmospherics. Dominick (TALK) 12:53, 14 November 2006 (UTC)
Sometimes you unintentionally get nice images of overhead power-lines where you think you are looking at the ground. The antennae try to have contact with the ground, however, it is difficult to focus this range of frequency (even with shielding), and power-lines provide lots of noise.+mwtoews 09:40, 20 December 2006 (UTC)


This is mentioned in the Richard Kregeg wiki article. There GPR is dismissed by historians ( what that means I am unsure of ) because it didn't find ground disturbance - of course this was at Treblinka ( really messed up a good story ). Is GPR reliable - if it finds that the ground has not been disturbed does it mean that the ground may have been massively disturbed or not. How would a 'historian" know the difference. I believe I recently saw GPR used in Mongolia? on a National Geographic archaeology show - they seemed to find it reliable but maybe it doesn't work well in Poland159.105.80.219 14:20, 5 January 2007 (UTC)

I don't know anything about the conditions at the site in Poland, but GPR is not effective in some soils, particularly those containing clay. This is well known, and experienced practitioners will use other geophysical methods where conditions are not appropriate for GPR. It is all too common, however, to see it applied inappropriately. Tapatio 22:57, 7 April 2007 (UTC)

[edit] Locate uranium deposits from space?

It is well-bandied-about that at current prices the world has 50 years of uranium deposits. (Note: fuel cost is very small in nuclear power plants, and price increases could easily be absorbed.) Is it possible to locate uranium deposits from space? Are there specific frequencies which Uranium-235 and Uranium-238 would reflect? Simesa 23:11, 5 July 2006 (UTC)

A radar of all types give the instrument an measure of the reflection coefficient. It would depends on specific ores and specific substrata. Usually buried objects can be found only a short distance underground. Specifically a particular element may resonate in a native ore at a particular frequency. Frankly when people say we are running out of element X, that usually precedes the discovery of a rich source or it starts the sales pitch for an investment scheme. Uranium in sea water and in undersea deposits have never ben exploited, so I would say we have many centuries of supply. Dominick (TALK) 12:53, 14 November 2006 (UTC)

[edit] Better illustration?

The figure used as an illustration in this article really isn't all that illustrative, as it does not show any distinctive refections. I have access to lots of GPR data, and could contribute something showing interesting subsurface features. Tapatio 17:35, 8 June 2007 (UTC)

I agree, and I've briefly looked for something through the USGS websites (because it is public domain), but haven't done a serious search .. you could try to help out by looking on their websites for something more interesting. +mwtoews 17:53, 8 June 2007 (UTC)

How about this (from my own work)?Tapatio 14:25, 11 June 2007 (UTC)

Yes, that is certainly improved, since there is something to see. I'll replace the first example photo.+mwtoews 16:44, 11 June 2007 (UTC)

I'm glad someone caught the parabolic vs. hyperbolic error. It was careless acquiescence to the spell check on my part. Tapatio 05:15, 14 June 2007 (UTC)

How about an illustration of GPR in use? Tapatio 17:34, 5 July 2007 (UTC)

[edit] Spam

It seems like the external links section is almost all spam. It has been tagged with a spam warning, but nobody seems to want to fix it. What criteria might we apply in deciding what is spam and what is not?

[edit] Keep

- sites that provide more detail/examples--CheMechanical 16:38, 31 July 2007 (UTC)
- sites with proprietary GPR techniques or equipment--CheMechanical 16:38, 31 July 2007 (UTC)

I would be inclined to discard commercial sites with proprietary GPR techniques or equipment. They are basically advertising their products or services. If such sites represent the mainstream of GPR practice or instrumentation, this should be treated in the body of the article. If they represent important advances, these could be mentioned in an appropriate section as well. Tapatio 20:49, 9 August 2007 (UTC)

[edit] Discard/Remove

- all others--CheMechanical 16:38, 31 July 2007 (UTC)

[edit] I did it

I have deleted the ugliest of the spam from the external links. I don't think any of them could be justified under wikipedia policy (see Wikipedia:External links, particularly Links normally to be avoided). I think that the links in the "Examples of GPR radargrams" section are a bit dodgy also, but they fullfill a need that is not currently met by the article. It would be nice to see a couple more examples of different applications and presentations within the article, then get rid of these links. Tapatio 15:09, 16 August 2007 (UTC)

[edit] Time slicing

In archaeology it has become the norm to view GPR data as time-slice plots of multiple lines of data, as well as vertical sections of individual lines. Is time slicing common enough in other disciplines to be discussed here? Tapatio 17:34, 5 July 2007 (UTC)

[edit] Inventor and date?

Can we get a quick blurb on who invented it and when it was invented? I wanted to find out if it existed back in 1980 to answer someone's question elsewhere, but I couldn't find that information here. I found information on one site that said it was invented "in the 1970's" for the military, but nothing more specific or useful as a citation. -- HiEv 09:34, 30 September 2007 (UTC)

GPR has been used earlier than the 1970s. In September 1976, I was on a Coast Guard C-130 (USCG 1351) flight where we had a NASA crew, mini-computer, and a Side Looking Radar system. We used this to fly Alaska's North Slope and over the (North) Polar Ice Cap. This Radar system provided the thickness of: sea ice, flow ice and permafrost. We flew tracks that went East from Point Barrow to Canada's Yukon Territory, and West to Cape Lisburne. DeanRB 22:02, 24 October 2007 (UTC) DeanRB

[edit] Limitations

The paragraph enumerating the limitations of GPR (The limitations of GPR are many in this current day and age...) seems a bit out of place in the introductory paragraph. Perhaps this subject can be spun off into its own heading. Tapatio (talk) 15:25, 22 May 2008 (UTC)

It should certainly be in its own section (below "Applications"), and I was going to move and reword it when it was added, but I haven't ... so dive in! (It also needs some references). +mt 16:38, 22 May 2008 (UTC)

I started a rudimentary section an limitations. I don't have specific references, but I think it is all common knowledge to people in the field and non-controversial (previously it had some POV issues). Feel free to edit, expand, or expurgate. Tapatio (talk) 18:44, 22 May 2008 (UTC)