08-22-2007, 05:14 AM
I doubt lava tubes filling up would actually cause earthquakes. It's usually pressure in the underground-to-surface paths, major earth settling, or plate movement (such as with this last one) that do. What we should be worried about is the surface flows turning into tubes, that then yield "breakouts" much lower down on the slope.
Time is an illusion, but a handy one. Without it, we would not be able to hear sounds, and without that ability, we would have no music.