Clay Diggins, you are sort of correct but not really. The H/V technique was invented in the 90s but has not been widely used. I'm a geophysicist with experience in the mining and petroleum industries going back 16 years. I've worked with lots of new technology including many different seismic systems. The technology that we're using is only 5 years old and we are some the first to be using it for placer exploration.
Seismic refraction using a traditional energy source has been used in placer lots, but it's expensive, requires cut lines, a crew and dynamite permits. You can do it without dynamite but you won't get as good of results, I know this from experience. The passive system doesn't have any of those requirements.
H/V can be done with tri-axial geophones but our system is specifically designed for this type of survey and we are using a new processing technique.
The resolution depends on the interpretation more than anything. The device is insanely accurate and each point is independent, it's not a line like traditional 2D or 3D seismic and you don't have CMPs or anything like that. As long as you have strong impedance contrast between layers you're accurate. When you have decomposed bedrock that can provide some uncertainty of the exact interface but you see the decomposed section too.
IMAUDIGGER, the listening time depends on several factors but we have settled on a 20 minute record time per station. We are using a sensor that is patented, it's not our invention but we do have our own unique processing technique.
Seden, You go ahead and have fun with your seisgun. You still need geophones and a line, etc. But knock yourself out.
ncclaymaker, we actually do UAV LiDAR too. How do you think we get the surface profile? We use photogrammetry or LiDAR depending on the situation. Those can't see into the earth. They map the surface only, you can't find a channel by surface map alone.
We're working on a cool new technology using our drones and a multi-spectral camera. It won't see into the earth but uses an NDVI technique to classify different types of vegetation. The idea is that certain types of vegetation like to grow in disturbed ground. We've had some success with this technique in the Yukon, especially in areas where there's permafrost. We're still working on that though. In the right areas it can be used as a wide area scanning tool to get an idea of where to look for channels, we have a long range drone that can cover 640 acres in one flight so this can be very economical.
The passive seismic system is exactly as I have described. It's real and it's spectacular.
