Seismogram
A seismogram is a record of an earthquake induced motion at a measuring station as a function of time. Seismograms are usually taken by seismometers. Seisometers 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.
Historically, seismograms were recorded on paper attached to rotating drums. Some used pens on ordinary paper. Others used light beams to expose photosensitive paper. Today, almost all seismograms are recorded digitally to make analysis by computer easier. Seismograms are very important for measuring earthquakes using the Richter scale.
Seismogram Media
A seismogram being recorded by a seismograph at Weston Observatory in Massachusetts
A detail of the seismogram
A set of seismograms for an earthquake from the USGS (click to see large version)
A container that stores a Develocorder film reel
A reel of develocorder film that contains the archive of seismograms recorded at Weston Observatory in Massachusetts, USA. The shelves on the background contains film archives.
Viewing of a Develocorder film
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Other websites
- An example seismogram Archived 2008-05-18 at the Wayback Machine
- REV, the Rapid Earthquake Viewer Archived 2006-01-12 at the Wayback Machine Seismograms recorded around the world from recent earthquakes (weeks old) as well as larger earthquakes from the past.