earthquakes

A Question for Geologists (and other scientists) Regarding the Deepwater Horizon Gusher, Well Pressure and EarthQuakes

Question for folks, particularly science-types:

The pressure from the Deepwater Horizon well, which forced the blowout, and the steady stream of escaping oil...is that pressure solely from the weight of the many atmospheres of water above it? ...or could some of it be from internal pressures?

Regardless, does anyone know whether releasing all that pressure will lead to settling of the surrounding crust/mantle, leading to possible shifts in pressure in plates and affecting/effecting earthquakes?