why is there lava?
Because the fountains of the deep cavitated away the dense rock above the basalt the lava under caused the mid-ocean ridges to form.
With the weight of the planet pressing down and the more flexible basalt exposed it pressed upward.
Its all apart of the hydroplate theory it explains the mid-ocean basalt mountains ranges when other mountains on the planet are not basalt.
When God stopped the fountains of the deep the mantle above the basalt on either side of the exposed basalt pressed down accelerating the uprising of the basalt mountains and hydralically pressed excess water beneath the trenches in response to this uprising.
The lava under the basalt mountains is still pressing upwards causing the tectonic plates to float quite slowly towards the trenches.
Edited by Charley, : No reason given.