1.   The plates slide toward one direction or another and, inevitably, their ridges move off the hot spots that found them.

2.   As the earth moves, the upper and lower steel plates would slide back and forth across each other.

3.   On the West Coast, the Pacific plate is sliding under the North American plate, pushing it up slightly, reducing the relative sea level rise somewhat.

4.   Other earthquake-prone areas, such as Southern California, involve a different kind of boundary where one plate is sliding past another, rather than toward it.