LIQUEFACTION

 

This happens when loose, moist soil or sand is shaken so hard that individual grains separate, turning the earth into a soft, fluid that can swallow entire buildings.  The soil will turn into a liquid.  And ground motions in regions of soft sediment are drastically affected compared to surrounding areas, so that much greater earthquake damage results, such as that in the Marina District of San Francisco following the 1906 and Loma Prieta (1989) earthquakes. The port zone of Kobe, Japan, was also damaged severely by liquefaction during the 1995 earthquake.