During an earthquake near Port Royal, Jamaica, the water-saturated sand on which the city was built vigorously shook. As a result, the sand particles lost contact with one another, giving the mixture the consistency of a thick milk shake. Anything supported by the ground, such as buildings and people, either floated or sank. One eyewitness stated: "Whole streets with inhabitants were swallowed up. . . . Some were swallowed quite down, and cast up again by great quantities of water; others went down and were never more seen." This is a description of ________.