Methane or CH4 gas is being released in vast quantities in the Gulf waters. Seismic data shows huge pools of methane gas at the location immediately below and around the damaged "Macondo" oil well. [...] With the emerging evidence of fissures, the tacit fear now is this: the methane bubble may rupture the seabed and may then erupt with an explosion within the Gulf of Mexico waters. The bubble is likely to explode upwards propelled by more than 50,000 psi of pressure, bursting through the cracks and fissures of the sea floor, fracturing and rupturing miles of ocean bottom with a single extreme explosion.

First Tsunami with Toxic Cloud

If the toxic gas bubble explodes, it might simultaneously set off a tsunami travelling at a high speed of hundreds of miles per hour. Florida might be most exposed to the fury of a tsunami wave. The entire Gulf coastline would be vulnerable, if the tsunami is manifest. Texas, Louisiana, Mississippi, Alabama and southern region of Georgia might experience the effects of the tsunami according to some sources.

Second Tsunami via Vaporisation

After several billion barrels of oil and billions of cubic feet of gas have been released, the massive cavity beneath the ocean floor will begin to normalise, allowing freezing water to be forced naturally into the huge cavity where the oil and gas once were. The temperature in that cavity can be extremely hot at around 150 degrees celsius or more. The incoming water will be vaporised and turned into steam, creating an enormous force, which could actually lift the Gulf floor. According to computer models, a second massive tsunami wave might occur.

Some random guy on the Internet says:

Contrary to what most of us would think as logical to stop the oil mess, actually opening up the gushing well and making it gush more became direction BP took after confirming that there was a leak. In fact if you note their actions, that should become clear. They have shifted from stopping or restricting the gusher to opening it up and catching it. This only makes sense if they want to relieve pressure at the leak hidden down below the seabed..... and that sort of leak is one of the most dangerous and potentially damaging kind of leak there could be. It is also inaccessible which compounds our problems. There is no way to stop that leak from above, all they can do is relieve the pressure on it and the only way to do that right now is to open up the nozzle above and gush more oil into the gulf and hopefully catch it, which they have done, they just neglected to tell us why, gee thanks. [...]

This down hole leak will undermine the foundation of the seabed in and around the well area. It also weakens the only thing holding up the massive Blow Out Preventer's immense bulk of 450 tons. [...] If you have been watching the live feed cams you may have noticed that some of the ROVs are using an inclinometer... an inclinometer is an instrument that measures "Incline" or tilt. The BOP is not supposed to be tilting... and after the riser clip off operation it has begun to... [...]

What eventually will happen is that the blow out preventer will literally tip over [... ] as the well casings cannot support the weight of the massive system above with out the cement bond to the earth and that bond is being eroded away. When enough is eroded away the casings will buckle and the BOP will collapse the well. [...]

All of these things lead to only one place, a fully wide open well bore directly to the oil deposit... after that, it goes into the realm of "the worst things you can think of". The well may come completely apart as the inner liners fail. [...] the very least damaging outcome as bad as it is, is that we are stuck with a wide open gusher blowing out 150,000 barrels a day of raw oil or more. There isn't any "cap dome" or any other such fixer device on earth that exists or could be built that will stop it from gushing out and doing more and more damage to the gulf. While at the same time also doing more damage to the well, making the chance of halting it with a kill from the bottom up less and less likely to work, which as it stands now?....is the only real chance we have left to stop it all.

Researchers aboard the F.G. Walton Smith vessel briefed reporters on a two-week cruise in which they traced an underwater oil plum 15 miles wide, 3 miles long and about 600 feet thick. The plume's core is 1,100 to 1,300 meters below the surface, they said.

"It's an infusion of oil and gas unlike anything else that has ever been seen anywhere, certainly in human history," said Samantha Joye of the University of Georgia, the expedition leader.

Bacteria are breaking down the oil's hydrocarbons in a massive, microorganism feeding frenzy that has sent oxygen levels plunging close to what is considered "dead zone" conditions, at which most marine life are smothered for a lack of dissolved oxygen.

Joye said her team also measured extremely high levels of methane, which is also spewing from the gushing BP well at up to 10,000 times background levels in Gulf waters. "I've been working in the Gulf of Mexico for 15 years," Joye said. "I've never seen methane concentration this high anywhere in the water."

When this blew out there had to be resevoir pressures of 40-50,000 pounds per square inch other wise the fire wouldn't have been so intense and what would have come out first is the blowout preventer would have popped out of the water more like a cork. And then what would come out second is the casing. [...] And so we have an open hole that's spewing I would guess somewhere between 100-150,000 barrels a day of oil which is why you now have over a hundred mile oil lake at the bottom of the Gulf of Mexico that's apparently 4-500 feet deep. [...]

I would think by the end of the week we will discover that we have an open hole with no casing in it which sits about seven miles away from where BP had been trying to fix these little tiny leaks in the drilling riser. I bet where (inaudible) of the drilling riser is still connected to the (inaudible) of it and so they've done everything wrong. [...]

They basically are trying to patch a little leak in the drilling riser. You've got to remember that what we're seeing on television, the drilling riser is 22.5" in circumferance. Most of it is a elastomers to make it bouyant. In the middle is a 7" column with the annulus where the drill bit goes down, so coming out of that is a little plume of gas. It's not oil and it's only about four feet high.

That could not by any way have actually covered 40% of the Gulf of Mexico, so what we're going to find when the Thomas Jefferson finishes its work is we have an open hole with no casing in it and the only way we'll shut it off is either let it complete which might take 30 years, which could maybe not only poison the Gulf of Mexico but maybe the Atlantic Ocean, or to put a nuclear device down the hole like the Russians did in the 70's and actually encase it by turning the turning the rock into (inaudible).