Split the raid into two groups. 1 consisting of 1 tank, 1-2 healers (Depending on the setup) and all of the DPS. The second group consisting of 1 tank and 1-2 healers (Depending on the setup).
Tank the two molten colossi at the two corners before the stairs.
Have the healers stay as far away from the corner as possible, leaving them out of line of sight of the molten colossus, thus leaving them unaffected by Earthquake
Make sure that tank and DPS is always in line of sight of the healers, but not the molten colossus.