Seismogram

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.

 Other websites 
An example seismogram 
REV, the Rapid Earthquake Viewer  Seismograms recorded around the world from recent earthquakes (weeks old) as well as larger earthquakes from the past. 

Category:Earthquakes
Category:Earthquake engineering