Seeking a Way to Detect Underground Voids in Lava

You might want to talk to the archaeologists involved in this project:

http://news.discovery.com/history/pyramids-egypt-nasa-satellite-110526.html

Please check back and let us know how this is going. You may or may not find anyone here with the knowledge to help you but there are a lot of people here who are interested in your results.

Maybe a bunch of dowsers will show up and offer their services.

Wouldn't the underground tunnels, tubes and chambers have to be flooded for dowsers to work?

Not being a dowser, I don't know all the finer points.

I really miss that region (used to live in Kennewick). Although there is evidence of volcanic activity in that area, I wasn't aware that there were lava caves/tubes/chambers. What is your focus? What do you hope to find?

Looking for Mel's Hole?

There are some geographic (as well as editorial) errors in that article. (As might be expected in "Coast to Coast" productions.)

Manastash Ridge is on the west side of the Yakima River; the Yakima Firing (now Training) Center is to the east of the river, roughly 15 miles away from the ridge.

The Ape Cave, near Mt. St. Helens to the SW, is an example of a rather large lava tube, roughly 10-30 feet diameter and over a mile long.

The DeLorme topographical atlas has a joke symbol of a sasquatch about 13 miles NNE of Mt. St. Helens.

You have asked most of the right questions.

If you google "Ground penetrating radar" (Or "locating underground pipes") you will come across three different types of entry. Those that want to tell you what GPR is and the theory of operation, those that want to sell you GPr equipment or accessories and those that contract their services using GPR.

There are conractors out there who provide services to sewer authorities to locate underground pipes (especially plastic ones with no meatalic trace).

GPR has some limitations that work in your favour for voids in solidified lava.

The greater the difference in density of the surround and the void the better. That's why they offer to find sewer pipes (mostly full of air), but rarely offer to find water pipes.

The lava should have a reasonably consistent density, so there should not be intermediated density changes to give false reflections.

You can use different frequencies to "look" deeper into the material.

Have fun!!

Using infrared they continue to find civil war soldier graves in many soil types. This is similar to what artsmith describes for locating the pyramids.

The size of what you are looking for determines how far away you need to be to "see" the difference in temperature, the solar heating provides the heat source, which a void looses its heat quicker then a solid, but the depth and size of the void determines the rate of heat loss. If the void is large you may only see an edge, if the void is at a descending angle.

I have had a professor from New England who wanted to look for the underground caverns in Florida with an infrared camera mounted to an unmanned aircraft and transmitting video to a receiver at his mobile location on the ground.

Usually the infrared camera has a very wide angle lens between 25 and 5mm depending upon how big an area you want to see and the number of pixels in the infrared camera detector. For a 256x256 pixel detector and 5mm lens at 5,000 ft each pixel is about a 3x3 foot area on the ground. Flying slow, using high-high sensitivity infrared camera (check out www.infraredcamerasinc.com ).

The application is very similar to border patrol. You will want a visible camera and an infrared camera looking at the same area at the same time, i.e concentric focused, auto focus is unlikely to work due to changing scene (best to get into the infinity focus part of the lens), and probably sychronized shutters will make it easier to match the images.

no problem...

the device is called a "Drilling Rig"... and can easily and routinely detect those types of things.

that was easy

chris

Check with the USGS for Cross hole Tomography. I have first hand experience and this type of Cross hole will show you the tunnels or lava tubes quite well. The USGS would be a good place to check. Check out this link http://walrus.wr.usgs.gov/geotech/highres/. Good hunting.

Good suggestion. I think USGS has a large office in Vancouver, WA to study Mt. St. Helens - about 40 miles or so from me - and the other Cascade volcanoes, among them Mt. Adams, which is about 8 miles from me. I'll give them a call after the 4th and ask about Cross hole tomography. Thanks.

Thumper truck and seismic equipment same way they explore for oil and gas.

There are a number of Geophysical methods that might be employed for this. One method that I recall from my Geophysics course many years ago was seismic refraction.

This method measures the change in velocity and direction of a seismic wave as it encounters a change in density of the underlying rock or soil. An open void in the rock would stand out clearly.

I recommend that you contact the Geology department of your state university. I am sure that they will have the necessary equipment. Your interest may lead to a good project for a Geophysics student.

Depending on depth, take a look at this website.

That looks like just what I need. The cases on their site show examples of work almost identical to what I have in mind. Thank you.