In every other O.T. place, the deep has a bottom, as it does here, shown by the fact that its bottom was seen and became dry when the water was “gathered into one place” (Gen. 1:9). The “great deep” (rav tehom), that had fountains opened during Noah’s Flood ( Gen. 7:11), never is elsewhere said to refer to the ocean! In the only other time it refers to a place, Amos 7:4 says, “Thus Yahweh showed me, and behold, Yahweh was calling to contend by fire, and it consumed the great deep (rav tehom) and began to consume the farm land.” The word translated, “fountains,” (magyahn), in Genesis 7:11 and 8:2, appears 23 other times in the O.T. and “water” is the only substance associated with it. Isaiah 30:33 speaks of “a stream of fire and brimstone.” No such stream is spoken of in conjunction with Noah’s Flood. So to say the vast majority of Earth’s volcanism happened during Noah’s Flood, is based on a non-Biblical assumption. (see p.63 in my: BEFORE GENESIS)