seismograph

American  

[sahyz-muh-graf, -grahf, sahys-] / ˈsaɪz məˌgræf, -ˌgrɑf, ˈsaɪs- /

noun

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

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seismograph British  

/ 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

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seismograph Scientific  

/ sīz′mə-grăf′ /

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.

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Other Word Forms

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

Etymology

Origin of seismograph

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