They were still "ditch-witching" in my country as late as the early 1980s.

Ditch-witching was a form of seismographic exploration for oil and gas. Like any of the seismograph techniques, you set sensitive listening devices, called geophones, in the surface of the ground, and they record the echoes of loud noises, made on or near the surface, as they bounce off the different geological structures below. But in ditching-witching, the source of the loud bang for the sensors to detect was explosives laid in a long ditch in the ground.

Explosives are set off, and here come the echoes. 'Course, they left a chunk of the countryside looking like it had been bombed, because, in effect, it had. And everything with wings or feet left the country.

Next technological advancement we saw was similar, but the explosive was hung in a bag from a pole a meter or so above the ground. Just as noisy to the above-ground world as ditch-witching, but less destructive to vegetation and soil. But just as hazardous. Not the sort of thing you can set up and then wait until tomorrow, or next spring, to set off.

Then came the drilling rigs. Light, mobile operations that would drill a hole, 30'-60' deep, with the explosive set at the bottom of the hole, with the detonator wires running to the surface. Got to see a demonstration of that once. They drilled the hole faster than I could imagine, and set the explosives. Then you have to refill the hole, using water and bentonite. They told us, if you didn't get the hole backfilled properly, you and everyone else will know, 'cause the mud will come flying back up like a geyser.

When they set off the blast, you could barely hear the muffled "whump" below your feet (yeah, we stood right there, not four or five meters from the hole). You could feel it better, like a vibrating shimmy up through your toes. Loose dirt on top of the hole shivered like a train was passing.

And that was it. They didn't disturb any more dirt than a really hungry badger. If it wasn't for all the truck traffic and new roads across virgin countryside, in a year you'd never know they had been there.

I passed a crew setting out their line over twenty years ago, right perpendicular to the highway. Since then, the highway department built a 12-foot snowfence across the perfectly straight two-track road the seismograph crew created.

Everyday I go by there, like yesterday, I kick myself for not taking a picture of that crew out there making their road.

Because it is still there. Probably twenty years later. With absolutely no traffic on it since that day.

But when I encountered this sign

north of Picket Lake yesterday, I knew there would be no explosives going off.

The modern seismograph companies use vibrators.

And no, not the hand-held kind. These vibrators are huge.

These big-tired machines have a metal plate on their belly, and when at the proper site, hydraulics push the plate down onto the ground, lifting the rest of the vehicle literally up in the air. And the engine vibrates the plate for a few moments, at the same time that the three or four machines in the crew are vibrating.

Then they move on to the next site.

The echoes of those vibrations are read by the network of geophones laid out on the ground, and connected by electronic cables and radio to this trailer:

So. What's the problem with the new system?

Roads. Lots and lots of roads. With the progression of computers and software, the product of seismograph work now is essentially a 3-D picture of the geological structures under the ground. But to get that database, like with CAT scans, you need lots and lots of pictures, or echoes. With these 3-D projects, the huge vibrators essentially drive criss-crossing lines every quarter to half mile.

On hard ground, you'd probably never know they'd been there after a year. Softer stuff, like the clay soils of the Honeycombs, and those ruts might be there for a decade or more.

We sometimes have to choose. Do these machines follow each other single-file to each vibration point, thereby creating huge new roads,

or do they drive side-by-side, thereby avoiding deep ruts, but covering five to six times as much ground. I did the figures on one project. Side-by-side, those big rigs would have physically driven over six percent of roughly four townships (~144 square miles) they were covering.

That's a lot of nests to lose. Of anything (except maybe starlings).

Not to mention the geophone network. Takes a lot of people to get those laid out, and they are always moving them as the vibrators shift into new ground. Either a lot of trucks, ATVs, or as with this outfit,

helicopters.

So, a remote, favored part of my desert now has new scars.

But that is nothing compared to what is to come. They don't waste 3-D money on speculative explorations. The companies do this because they know the gas is here, they just want to know exactly where.

The gas wells will be coming. Complete with bladed, all-weather roads, pipelines, flaring waste pits, and noisy compressors.

Soon.