Increasingly as the pole shift nears, the Earth will give evidence of the compression and tension in her surface by what humans will perceive to be sonic booms. The mechanism is in fact the same, clapping air masses, the same mechanism that produces thunder. Where thunder is caused by air masses separated by what is essentially a vacuum created by the superheating lightning bolt, and where sonic booms are caused by a compressed air mass pushed in front of the plane exploding back to equalize with the thin air mass trailing the plane, pre-cataclysm booms are caused by heaving in large bodies of water. Earthquakes where plates are compressing are measured by humans as the friction causes jolting, but for every compression adjustment there is, somewhere, a widening in a rift. Most often these rifts lie underwater, as water fills low lying places. A widening rift does not jolt the bordering plates, it is a silent adjustment. However, the sea water rushing to fill the new void has an effect on the air masses above, creating a thin air mass and causing the air on all sides of this thin air space to rush in, and clap!