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nouna measuring instrument for detecting and measuring the intensity and direction and duration of movements of the ground (as an earthquake)
Definition that contains seismograph
- mercalli scale a scale formerly used to describe the magnitude of an earthquake; an earthquake detected only by seismographs is a I and an earthquake that destroys all buildings is a XII
- richter scale a logarithmic scale of 1 to 10 formerly used to express the magnitude of an earthquake on the basis of the size of seismograph oscillations
- seismogram the graphical record of an earth tremor made by using a seismograph