Seismograph:
A device that detects vibrations in the earth.It is used in studying the earth’s interior and in prospecting for probably oil-bearing structures.
Vibrations are created by discharging explosive in shallow boreholes, by striking the surface with a heavy blow, or by vibrating a heavy plate in contact with the ground.
The type and velocity of the vibrations are recorded by the seismograph indicate the general characteristics of the section of earth through which the vibrations pass.
