An apparatus for registering the shocks and undulatory motions of earthquakes.

An instrument for magnifying and recording the motions of the Earth's surface that are caused by seismic waves.

A device that records natural or manmade vibrations from the earth. Geologists read what it has recorded to evaluate the oil potential of underground formations.

A graph that is produced by a seismometer, showing the magnitude and length of earth movements. siesmic earthquake Richter