seismograph

References & Edit History Related Topics

Images & Videos

Anderson-Wood torsion pendulum seismograph

Bronze replica of Zhang Heng's ancient seismoscope featuring a central ornate vessel with dragon heads around its sides and open-mouthed toads positioned below each dragon.

Palmieri, Luigi: seismograph

Diagram of a horizontal pendulum seismograph showing a suspended mass on a boom attached to a pivot, with a silk thread, mirror, oil lamp, thin plate with slits, and a recording drum with photo-sensitive paper to capture seismic activity.

Press-Ewing seismograph

The video thumbnail image shows a woman trying to break a bundle of pasta strands as part of a scientific demonstration.

How the Richter scale measures earthquakes

Diagram showing a strain seismograph with two piers connected by a rod. Three panels illustrate the rod's position during no seismic activity, compressional wave activity (rod moves closer to pier 1), and stretching wave activity (rod and pier 2 move away from pier 1), demonstrating how changes in distance measure seismic waves.

Diagram showing four main types of seismic waves: P wave with alternating compressions and expansions, S wave with vertical undulations, Love wave with horizontal shearing, and Rayleigh wave with rolling elliptical motion.

Graph showing travel-time curves for seismic waves, with time after initial rupture on the vertical axis and distance from earthquake epicenter on the horizontal axis. Three lines represent primary (P) waves arriving fastest, secondary (S) waves arriving next, and Rayleigh and Love waves arriving slowest.

seismograph: References & Edit History

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Article History

Type	Description	Contributor	Date
	Deleted Web site: Geosciences LibreTexts - Measuring Earthquakes.	Gloria Lotha	Sep 17, 2025
	Media added.	Meg Matthias	Aug 14, 2024
	Add new Web site: Geosciences LibreTexts - Measuring Earthquakes.	Emily Rodriguez	Aug 23, 2023
	Added a photograph of the Press-Ewing seismograph and a diagram of a travel-time curve.	John P. Rafferty	Nov 28, 2017
	Description of Sir James Alfred Ewing changed from "British physicist" to "Scottish physicist."	John M. Cunningham	Mar 15, 2017
	Media added.	Mic Anderson	Jun 10, 2016
	Illustrations depicting the Wood-Anderson seismograph and seismic exploration, a photo showing the placement of seismic instruments on the Moon, and a video describing the Richter scale added.	John P. Rafferty	May 09, 2016
	Media added.	The Editors of Encyclopaedia Britannica	May 09, 2016
	Add new Web site: United States Geological Survey - Earthquake.	Emily Rodriguez	May 02, 2016
	Add new Web site: Michigan Tech - UPSeis - How Are Earthquakes Studied?	Emily Rodriguez	May 02, 2016
	Add new Web site: Incorporated Research Institutions for Seismology - Seismographs.	Emily Rodriguez	May 02, 2016
	Added new Web site: How Stuff Works - Science - Seismograph and Richter scale.	Gita Liesangthem	May 16, 2007
	Added new Web site: Seistronix - RAS-24 Exploration Seismograph.	Dutta Promeet	Jan 11, 2007
	Added new Web site: Seismic Education Site - UPSeis.	Marco Sampaolo	Jun 13, 2006
	Added new Web site: Seismic Education Site - UPSeis.	Marco Sampaolo	Jun 13, 2006
	Article revised.	The Editors of Encyclopaedia Britannica	Apr 28, 2005
	Article added to new online database.	The Editors of Encyclopaedia Britannica	Jul 20, 1998