P.S. I am pro-fracking
A volcano is a BIG fissure.
No, that is pressure exceeding the force of gravity.
But, my original post accounts for that as hydraulic fracturing creates pathways of least resistance into the borehole.
So your post is pointless.
I’ve done many percolation tests.
The water is not ‘wicking’ up in the soil. Simple gravity is actually at play.
Here are the usual ingredients, for having a shallow water table:
1. You are in a low area - i.e., there are adjacent areas, which are at least slightly higher.
2. Shallow rock ledge
Some of the rainwater in the area goes down into the soil, as per usual. However, it can’t get past the rock ledge, and becomes ‘perched’ on the rock. The water will eventually migrate to the lowest point on this rock ledge, which is usually the lowest point on the top surface.
The water can even come out of the ground, if the elevation difference is enough (think mountain spring).
As an example, if my per test is at elevation 100, and there is nearby ground at elevation 110, and the rock is 10 feet deep at 100, I would expect groundwater on my lot to be immediately below the surface. When I dig the perc hole, and see the water fill the hole, it is actually seeping in from the sides...essentially ‘falling into’ to hole. And, it may bubble up from the bottom, due the the energy gradient between the perched water and the hole. But the energy gradient is due to gravity (think hose level), and certainly not defying it.
Liquids can ‘wick’ and defy gravity. But, the weight of the water in the aquifer would actually push groundwater down any cracks in the rock, inhibiting any wick action. Also, somebody smarter about fracking than me may have info on the surface tension of fracking fluid, and whether or not wicking is probably.