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The Collaborative International Dictionary

Seismogram \Seis"mo*gram\, n. [Gr. ? earthquake + -gram.] (Physics) The trace or record of an earth tremor, made by means of a seismograph.

Douglas Harper's Etymology Dictionary

record made by a seismograph or seismometer, 1888, from seismo- + -gram.


n. (context geology English) The graphical output from an accelerograph or seismograph.


A seismogram is a graph output by a seismograph. It is a record of the ground motion at a measuring station as a function of time. Seismograms typically record motions in three cartesian axes (x, y, and z), with the z axis perpendicular to the Earth's surface and the x- and y- axes parallel to the surface. The energy measured in a seismogram may result from an earthquake or from some other source, such as an explosion. Seismograms can record lots of things, and record many little waves, called microseisms. These tiny microseisms can be caused by heavy traffic near the seismograph, waves hitting a beach, the wind, and any number of other ordinary things that cause some shaking of the seismograph.

Historically, seismograms were recorded on paper attached to rotating drums. Some used pens on ordinary paper, while others used light beams to expose photosensitive paper. Today, practically all seismograms are recorded digitally to make analysis by computer easier. Some drum seismometers are still found, especially when used for public display. Seismograms are essential for finding the location and magnitude of earthquakes.

Usage examples of "seismogram".

Whetstone stood together at the front of the room, before an alarming seismogram display showing an almost constantly increasing amplitude on all crests.

The boys who run my explorations department can write a street address for any seismogram and some pieces of rock.

I wrote to Louis right away, but all he said in reply was that if I cared to come and check the figures against the seismograms his office had prepared I'd find them accurate.