Questions and answers about treasure hunting and geophysics

[99thpercentile]

I haven’t seen many good posts here for a while so I want to propose something.

Ask specific questions here about how geophysics relates to treasure hunting.

For example, I had a recent question about what type of sensor may have produced a picture that was shared with me. The person said the picture was of a plastic 55 gallon drum. I did my best to explain what type of instrument most likely produced that image, why I thought that, and what the rustles would have looked like from other types of sensors.

I was asked once by the drug enforcement agency (DEA) to help locate plastic 55 gallon drums buried by drug dealers on beaches in the Caribbean that may have been full of cash and jewels.

 

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[ConceptualizedNetherlandr]

My first question is: were they full of cash and jewels?

 

[ConceptualizedNetherlandr]

My second question is: I still use my old 1980's copy of geophysics by Telford. Has that been found to stand the test of time or were there errors or shortcomings?

 

[99thpercentile]

The bad news about the DEA request was that they decided not to do it after we explained how long it would take to do the surveys. They thought I could walk up and back twice along a beach and then be done. We had to explain that our like spacing would need to be less than the smallest dimension of the target.

I think that last edition of Telford was published around 1993, it is a fine book for the technical underpinnings of most geophysical methods. It doesn't really address modern ground penetrating radar (GPR) instrumentation or processing, it doesn't address mobile time domain electromagnetic induction (TDEM), or any other method where there have been big improvements in collection speed and resolution. The biggest improvements in geophysical equipment are collection speed and resolution, the processing for some methods has significantly improved while others haven't changed much in 20+ years. A lot of near surface geophysics is bump detection and unfortunately there aren't too many ways to speed up that processing.

I typically recommend "An Introduction to Applied and Environmental Geophysics" by John M. Reynolds 2nd edition (2011) although I think he is writing a 3rd edition now. I also recommend "Field Geophysics 4th Edition" by John Milsom and Asger Eriksen (2011) for anyone interested in near surface geophysics.

 

[ConceptualizedNetherlandr]

Thank you. Very informative!

 

[Icewing]

I have been hunting a pre civil war military fort, and some other places with civil war activity.
I have always been interested in either a drone with Lidar or some type of GPR that doesn't cost as much as a car. My problem is I don't know where to start. Are you familiar with Lidar and would it even be useful on old forts and camps? Is there anything on the market for hobbyists that's worth buying?