the super plume of the like a mushroom cloud caused co2 generation, which caused seawater temperature rise higher. this caused large amounts of methane release from methane hydrate at the bottome of the sea. the temperature became 7-8 °C higher right on the equator and 25 °C higher at the north pole and the south pole.
"wait did it actually plume UNDERGROUND? that seems alot scarier than just being shot out a narrow line. " That's right, a big fat plume burst up from the deep layers of the Earth and piled up against the crust. The pressure had no where to go but burst out the crust, and so the hot rock oozed out and keept oozing out until all the pressure was gone.