With all the rain we are having, I noticed a weird spot in our gravel parking area. Periodically there are bubbles coming up from underground. (This is a gif made from a video clip)
Bubbles come up for a while, then stop for a bit. I knelt down and sniffed, but the only odor is wet gravel.
There are no pipes underground there. I’m assuming it’s a natural phenomenon, any geologists out there?
Is it flammable? See if you can light it. If so, I would suspect methane from decomposition of organic matter. Perfectly natural and not really dangerous, since there doesn’t seem to be much and it dissipates quickly. Another possibility is CO2 produced when acidic water reacts with limestone, but if it was CO2, it would have burnt your nose when you sniffed (not burnt like with a flame, but burnt like it does when you take a big sniff of your beer).
I would just suspect hollow spots underground with small openings, like insect/animal tunnels. About like the bubbles that come out of an empty bottle if you hold it under water. The water pushes the air out as it seeps into the hollow spot.
Where you shootin’ at some food?
I would say something like this. Not being all that far from you I know some people up off 422 by Worthington who have that a lot of the time during rains. Basically the ground water forcing out ground-trapped air. The gravel of the drive makes it show as bubbles more so than when it escapes from the grass. If it doesn’t light, don’t give it a second thought.
I took a torch out to the area just now. It stopped raining last night, and there’s no longer a puddle present. I waved the flame around the area and nothing happened.
Will try again if conditions recur.
I wonder if you know the same people I know in Worthington. Motorcycle enthusiasts, one a retired prison warden, one attends funerals, one a retired linebacker?
Small world, either way. 
Also, anaerobic digestion (decomposition) produces biogas, which is usually a less than half methane. The other half is mostly carbon dioxide. Unless it builds up, it doesn’t produce that much heat when it burns.
Ask them about Sunset Riders and the old HOG group from Butler; Yeah – I think I know at least one of the above. But the main person I was thinking of makes artificial body parts for accident/disease victims. And not just the usual leg and stuff but faces and things as well. Younger fellow than me by 20+ years but a good dude.
And this winter for sure ---- beer and a cigar somewhere.
Small World x 10000. Yeah, beers and cigars for sure this winter!
Forget the golf clap, this deserves a round* of applause.
I suspect it is just some dry space underground. As water ‘capped’ it off above and water soaked to the bottom it caused the air to be pushed out.
No harm no foul.
I don’t know, but that’s some damn fine looking gravel!
You maybe over an Indian burial ground. I would move. Those pesky ghosts don’t play.
Come to think of it, I think I saw this episode on Scooby-doo.
Yes, isn’t it though?
We are the last of three homes on a private lane. Most years we share the cost of a few truckloads of gravel. We also get mulch and topsoil from the same guy. He is so adept at dumping while his truck is moving, that we do not have to do much raking when he’s done.
This year’s gravel caught my eye.
Is that a low spot on the property?
Where I work, the back of the property has a retaining wall about 5 feet high. The entire rest of the block is at the height of that wall. After a good, hard rain, water comes up through cracks in the pavement (95% in one specific crack), over the next day or so. In Spring, water comes bubbling up for a good month or so.
I’m thinking this is similar, it’s a [local] low spot and after it rains, water is traveling just below the surface to wherever it ends up and that happens to be a good spot for it to bubble up as it passes.
Being it’s in Pennsylvania I suggest that spot is a fetal pothole waiting for pavement.
No. There are low spots in other areas where ground water sometimes surfaces, but this spot is not one of those.
Is there a water main running anywhere near it?
On my drive to work there’s one driveway that will have a fairly large puddle in front of it that lasts for days after it rains. All the roads were are dry an hour later, this one still has a puddle 72 hours later. My WAG is that there’s a water main down there with a slow leak. Not enough to draw too much attention, but enough to keep the ground saturated so rain water can’t readily soak in to it.
We have a well. Pipe from the well to our house is nowhere near the area.