Interactive Earthquake

Earthquakes are movements of the brittle portions of the Earth. These movements generally occur as a result of slippage along fault surfaces due to the release of frictional forces that build up along the fault. The rapid slip between two brittle blocks of rock creates a shock wave that is transmitted through the overlying rock to the surface where we feel it as an earthquake. A seismometer senses the vertical and horizontal motions of the ground resulting from the deep earth movement and displays these motions as squiggly lines on a seismograph. The magnitude of the earthquake, commonly reported as a number on the Richter Scale, depends on the height of the squiggles (amplitude) and the distance between the squiggles (period)

When you jump on the platform here, you are creating a shock wave that is measured by the seismometer and displayed on the seismograph. Someone who is bigger or jumps hard will produce larger squiggles than someone who is smaller -- in other words they are producing a bigger earthquake.

Links to Earthquake Information elsewhere:

• Earthquake Image Information System, U.C. Berkeley
• National Information Service for Earthquake Engineering Gopher Server

Volcanoes!