Bible tells that earth, meaning dry land, the original single continent, was stretched over vast water area called the great deep. Bible also tells that the flood came when the fountains of the great deep burst open. Logical conclusion from that is, for some reason the original continent was broken, which led to the situation where the water came from below the earth. And when the water came out, the parts of the obviously logically continent sunk. This all obviously caused massive sentimental formations first outwards from the fountains to the edges of the continent.World flood in 40 days is unbelievably sudden. Even in the Biblical narrative the ground DID NOT sink
Things that we can observe in nature suggests that when God formed the circle around our planet, it went about where nowadays is the "ring of fire". From that circle earth was originally stretched. And when the earth, dry land, was broken, it seems to have started from where we can nowadays find the Mid-Atlantic ridge.
I think the evidence for Biblical flood is overwhelming.