These powerful forces have different consequences at different depths. Some minerals suddenly rearrange their atoms into denser packing arrangements when the temperature and pressure rise above certain thresholds. This produces implosions a few hundred miles below the earth's surface. Because the flood occurred only about 5,000 years ago, temperatures are not uniformly hot at these depths. The reverse, a sudden expansion, occurs when the temperature and pressure drop below specific thresholds.
Shallow earthquakes involve a different phenomenon.
Trapped, subterranean water, unable to escape during the flood, slowly seeps up through cracks and faults formed during the crushing of the compression event. The higher this water migrates through cracks, the more its pressure exceeds that in the walls of the crack trying to contain it. Consequently, the crack spreads and lengthens. Simultaneously, stresses build up in the crust, again driven ultimately by gravity and mass imbalances at the end of the flood. Once the compressive stress has risen enough, the cracks have grown enough, and the frictional locking of cracked surfaces has diminished enough, sudden movement occurs.