This page is all about learning how to read seismograms, however many of the links referenced cover the subject of earthquakes as a whole. For the most part it relates to earthquakes, but there are some specific volcano related materials as well.
I have divided the section into two parts, one for straight reading, and one where there are exercises for you to try. These many be paper or interactive.
Before you begin, if you know nothing of this then the description that follows may help:
Think of reading a seismo this way. Take a bobblehead on a dashboard of a car – put a pencil in it’s mouth – put a piece of paper moving past in a straight line on rollers going across moving like film in your old fashion reel camaras. ok – so your driving along on smooth pavement and all you get is a straight line going along the moving paper – then WHAM, Pot Hole – bobble head shakes violently, you get a massive spike on the paper – and then as the bobble head slows bobbling, the shakes lines get smaller and smaller until you have a flat line again. Volia! You have just read the instrument showing a quake.
Did that make sense?
Adapted from this source with the poster’s permission.
All links are to web pages unless specifically mentioned otherwise. All links open in this page unless noted otherwise.
Materials with Exercises
- Seismogram Analysis (University of Bergen)
Very good, and has learning check at the end.
Reading a seismogram (PDF)
Shows ground vertical movement recorded by a SLU seismic station at Cathedral Cave, Missouri (CCM) during a magnitude 4 earthquake near New Madrid on Sept. 26, 1990. and has some useful exercises associated with this event.
Virtual Courseware: Earthquake
This activity illustrates how seismic waves are used to determine the magnitude of an earthquake and to locate its epicentre.Trigger explosions and see the results on seismograms.
A certificate of completion as a virtual seismologist will be granted once the activity and quiz are successfully completed.
USGS How Much Bigger Calculator
Lets you calculate the difference between two earthquake magnitudes.
Earthquake Magnitude and Intensity – Excercise 2 (PDF)
Not for the faint-hearted. Requires a certain amount of understanding of the subject.
The applet simulates a seismometer’s reaction to an adjustable ground motion w(t). The displacement x(t) of the movable mass relative to the case is calculated recursively from the case (=ground) displacement w(t), based on the second order differential equation……
- A nice easy look at most aspects of earthquakes for the non-technical reader.
- IRSI animations all about earthquakes. Many of them.
- Seismic Signatures: How do I read a seismogram? (PDF)
Sumatra December 2004 – Reading the seismogram (PDF)
An excellent PDF file by the Guardian newspaper in the UK that will help you understand seismograms. This ons is looking at the December 2004 earthquake in Sumatra as seen on a seismograph in Italy.
You can view the original Guardian article here.
Triangulating the Epicentre of an Earthquake (PDF)
Part of an educational curriculum but has some useful information on it. (Very minor amount of self testing if you want.)
Earthquakes ( Laboratory 8 )
Introduction: In this lab we will study the three types of faults that can form. Next, we will look at how and earthquake forms along a fault. Then we will see how a seismometer records an earthquake and how the location and magnitude are determined. Finally we will look at the relationship between earthquakes and plate tectonics.
(At the end of the document there are 2 links to little excercises you can try.)
GeoNet (New Zealand) – Seismic Monitoring of Volcanoes
This is an excellent guide to reading the seismograms, especially as relating to volcanoes.
1999 AUG17, Turkey Earthquake
Explains the readings for that magnitude 7.8 earthquake.
1999 JUN15, Washington State Earthquake
Takes a look at the seismogram readings for that Magnitude 5.5 earthquake.
The Oklahoma Geological Survey Seismogram, Spectrogram, and Magnetogram Index
There are other examples of seismos and a mine collapse example.
Earthquakes and Society
by Courtney Brunious and Amanda Warner.
- Earthquake (PDF)
- Faults & Earthquakes
- Seismic Waves
- Effects of Earthquakes
- Measurement of Earthquakes
- Distribution of Earthquakes
- Earthquake Prediction
- Interpreting seismograms – Natural Resources Canada Web
Seismic data plots (seismograms) provide a visual record of earthquake activity, as well as other vibrations in the earth caused by natural and man-made phenomena. For example, seismographs located near shipping routes are able to detect the passage of freighters and cruise ships. (Good page this – worth a look!)
- Foreshock – Main shock – Aftershock Sequence