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


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

Origin of seismograph

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

Related forms

seis·mo·graph·ic [sahyz-muh-graf-ik, sahys-] /ˌsaɪz məˈgræf ɪk, ˌsaɪs-/, seis·mo·graph·i·cal, adjective Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for seismograph

British Dictionary definitions for seismograph


/ (ˈsaɪzməˌɡrɑːf, -ˌɡræf) /


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

Derived Forms

seismographic (ˌsaɪzməˈɡræfɪk), adjectiveseismographer (saɪzˈmɒɡrəfə), nounseismography, noun
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Science definitions for seismograph


[ sīzmə-grăf′ ]

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.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.