Describe where and how groundwater is stored in regions above the water table.?

Question

What roles do temp. and pressure play in the eruption of the geyser?

Answer 1

If it is groundwater by definition it is BELOW the water table.

http://geology.about.com/od/structuresla...

Answer 2

there is always a percentage of water above the water table, clinging to soil particles through cohesion and adhesion.

The water table is a boundary that exists where the water pressure is equal to the soil pressure, creating 'free' water.  Above the water is a vadose zone, which can be inches to several feet where the water is pulled up from the water table through capillary action, as well as other forces.  The vadose zone is below soil pressure.

Water can also be 'perched' - meaning there's a local zone of water (with it's own water table) suspended in an ordinarilly dry formation by an impermeable or low permeable layer.

As for geysers... they're based on a temperature inversion.

Cold water is denser than warm water, so in a perfect world, cold water would sink in warm water.  In a geyser, the water is heated from the bottom, often to boiling, but the cold water above forms a bubble, keeping the hot water from escaping.  After a certain amount of pressure builds, the energy of the hot water wanting to float overcomes the downwards pressure of the cold water and it shoots out.  

More temperature or more pressure would give you a more dramatic display and/or faster turn-around time.