Many low lying coastal areas are built on soils that will turn to mush with violent shaking causing buildings to sink.
http://en.wikipedia.org/wiki/Soil_liquefaction
Try this little “liquefaction” demo at home:
Fill a regular baking tray with clean, dry sand to about one inch in depth. Set a few small objects of various size and weight on top of the sand. For example, you might use a “Pink Lady” type pencil eraser, a marble (or small pebble), and a quarter.
Pick up the baking tray, hold it flat in front of you, and shake it side-to-side; gently at first, and then with increasing force.
Note what happens to the objects you put on top of the sand.
Try repeating the experiment a couple of times after adding water to the sand. Do it once with the sand moistened throughout, then again with the sand thoroughly saturated, though not to the point where there is standing water on top.