Accelerograph

An accelerograph can be referred to as a strong motion seismograph, or simply an earthquake accelerometer. They are usually constructed as a self-contained box, more commonly now being connected directly to the Internet.

Accelerographs are useful for when the earthquake ground motion is so strong that it causes the more sensitive seismometers to go off-scale. There is an entire science of strong ground motion, that is dedicated to placing accelerographs in the vicinity of major faults. The type of information gathered (such as rupture velocity) would not be possible with the standard seismometers. The best known example is the Parkfield Experiment which involved a massive set of strong motion instrumentation.