The Richter scale is logarithmic, which means that each increase in magnitude indicates a tenfold increase in the strength of the quake. In terms of the energy released, the differences are even greater. Seismologists have developed other magnitude scales based on measurements of body waves or surface waves. But these, too, are not accurate for all earthquakes. Body-wave magnitudes, for example, aren't accurate for very strong earthquakes.
Seismic waves weaken with increasing distance.
The 1989 Loma Prieta quake. Groundshaking is not the only hazard people face during earthquakes. They can also trigger landslides. In 1692, the town of Port Royal, Jamaica, slid into the sea and came to rest 50 feet below the surface. In 1959, archaeologists found a pot of turtle soup in one buried home, still sitting in its copper kettle.