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

Explanation

A seismograph is an instrument scientists use to measure the strength of an earthquake. Geologists or geophysicists who study earthquakes are called seismologists, and the tool that helps them study the shaking of the ground is called a seismograph or seismometer. It is usually installed at ground level or slightly underground, and it measures how intense an earthquake is. Seismograph comes from the Greek words seismos, "earthquake," and graph, "writing."

Example Sentences

They then analyze the simulated wave patterns at seismograph locations and compare them with real seismograms, which are graphical records of ground motion from actual earthquakes.

From Science Daily • Jan. 6, 2026

The technology might bear little resemblance to Palmieri’s electromagnetic seismograph, and his heroics are no longer needed in a world where scientists can monitor volcanoes safely from afar.

From Scientific American • Aug. 16, 2023

To go further back in time, Bromirski gathered data from seismograph records held in UC Berkeley’s archives.

From Los Angeles Times • Aug. 1, 2023

Earlier this month, data from the InSight probe's seismograph provided novel data about what Mars' core looks like.

From Salon • Apr. 28, 2023

They were not simply swinging, for the period of the undulations differed from that of the seismograph when set swinging, and also varied in successive undulations.

From A Study of Recent Earthquakes by Davison, Charles