It has been reported([1]) that when a loosely packed column of saturated sa
nd in a vertical cylindrical container is shock loaded axially by dropping
to the floor, large horizontal cracks initiate, grow and eventually fade aw
ay in the sand as it settles under gravity. This paper shows that a similar
phenomenon can also be observed when shock loading is replaced by forcing
water to percolate upward through the sand column. It is believed that our
result sheds further light on the physics of formation of these cracks.