http://people.csail.mit.edu/jaffer/Deepest
	The Deepest Hole in Miami

When you drill a hole into the ground in South Florida, eventually you reach water in (sand or) porous rock. If you drill further, you will penetrate a succession of aquifers. Do they go on forever?

The Spa

Drilling a well for use in irrigation typically took between one half day and two days to complete. The spa's well would go much deeper. Miami is sitting above the Boulder Zone, which puts the Lower Floridan Aquifer at a depth over 850.m.

Pile-driving so deep a well seems a challenge. Rotary drilling can compensate for some irregularities because the shaft turns. Buck was welding length after length of pipe onto the column being pounded down. Uneveness in the rock being cut or in the first welds could make the shaft wander away from vertical. The more the shaft curves, the slower the progress towards depth. If an upper weld brakes, the column might diverge from its lower section.

After four days of drilling, the workers stopped for the weekend. The well tip must have been only centimeters from their goal. On Sunday my father received the telephone call that a geyser had erupted from their rig, spraying a great plume of scalding sulfurous water which stained adjacent buildings.

I pondered the geyser incident for quite a while. As a youngster, I thought we lived in the most geologically dull place on earth (Miami). Was the hot water evidence that magma was close enough to the surface that a volcano might erupt in Florida?

Sadly (for bored children), the answer is no. The earth's core is hotter than its surface. Thus, there is a heat gradient increasing with depth. Drill deep enough anywhere on the planet and you will find warmth.

At several locations in Matheson Hammock Park there seem to be seeps of the dark, foul smelling water from the underworld. Its hard to imagine how that water would travel to the surface from such a depth. Perhaps decaying mangrove leaves are instead responsible.