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
• seismography
  noun
• seismographic
  adjective
• seismographical
  adjective

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

See Examples For:

seismograph

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

It became the electromagnetic seismograph, the first instrument that measured earthquakes in a way that wasn’t solely mechanical.

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

Both occurred on the opposite side of the planet from the InSight seismograph, which is useful for interpreting what exactly the energy waves were traveling through before it reached InSight.

From Salon ● Apr. 25, 2023

For the first time in my life its even course began to waver: the needle registered warning marks on the matrimonial seismograph, lines vague enough, but lines.

From The Man in Lower Ten by Rinehart, Mary Roberts