seismograph

[sahyz-muh-graf, -grahf, sahys-]

noun

1. any of various instruments for measuring and recording the vibrations of earthquakes.

seismograph

/ saɪzˈmɒɡrəfə, ˈsaɪzməˌɡrɑːf, ˌsaɪzməˈɡræfɪk, -ˌɡræf /

noun

1. Also called: seismometer. an instrument that registers and records the features of earthquakes. A seismogram ( ˈsaɪzməˌɡræm ) is the record from such an instrument

seismograph

1. An instrument that detects and records vibrations and movements in the Earth, especially during an earthquake. Most seismographs employ a pendulum mounted within a rigid framework and connected to a mechanical, optical, or electromagnetic recording device. When the Earth vibrates or shakes, inertia keeps the pendulum steady with respect to the movements of the frame, producing a graphic record of the duration and intensity of the Earth's movements. Separate instruments are needed to record the north-south horizontal, east-west horizontal, and vertical components of a tremor. By comparing the records produced by seismographs located in three or more locations across the Earth, the location and strength of an earthquake can be determined.

Other Word Forms

• seismographic adjective
• seismographical adjective
• seismography noun
• seismographer noun

Word History and Origins

Origin of seismograph¹

First recorded in 1855–60; seismo- + -graph

Example Sentences

After the fact, seismologists study measurements of the ground’s movement taken by seismographs and evaluate the damage done by the quake to decide what magnitude to assign to the event.

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When a patient is having a seizure, these lines jump up and down dramatically like a seismograph during an earthquake -- a signal that is easy to recognize.

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When the edge of two tectonic plates shift to produce an earthquake, the seismic waves it emits are measured by seismographs all over the world.

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These anomalies can be observed when seismographs pick up signals from earthquakes.

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Eventually, the researchers want to integrate the system with physics-based models, which could be important where data is poor, or places such as Cascadia, where the last major earthquake happened hundreds of years before seismographs.

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