Activity 3 - How Big Was It?

Use the resources listed below to help you complete this activity.

State-Based Resources
General Resources

State-Based Resources: Investigate - Part B: Measurement of Earthquake Wave Amplitude

Visit the Virtual Earthquake web site and simulate a new earthquake.

State-Based Resources: Inquiring Further

1. Does your community experience frequent earthquakes? Maybe you would like to help seismologists when an earthquake happens in your community. The Earthquake Felt Report Form allows you to contribute your intensity observations directly to seismologists so that they can construct isoseismal maps. Visit the following web sites to find the address that will let you know the kinds of observations you need to detect and record.

   Description of the scale currently used in the US. Includes a good explanation of the difference between intensity and magnitude.
   
   Includes an earthquake intensity location map of North America. Allows searches for specific earthquakes by city and state, so you can look up the intensity of earthquakes that have shaken your community.

3. Write down other questions you have about the ways earthquakes are measured. How would you go about gathering information to answer these questions? Write your ideas in your notebook. Visit the following websites for suggestions of useful web sites to explore:

   Explains how seismographs work, includes diagrams of seismographs and also reviews P and S wave motion and explains how to read Travel-Time curves.
   
   "Seismometers, Seismographs, and Seismograms" - USGS Cascades Volcano Observatory
   
   Description of the Global Seismic Network (GSN) and how it is used to study earthquakes around the world.
   
   Monitoring Earthquakes Around the World - USGS Fact Sheet 146-97
   

General information related to this activity:

Seismometers

Seimographs from the USGS
Explains how seismographs work, includes diagrams of seismographs and also reviews P and S wave motion and explains how to read Travel-Time curves.

"How are Earthquakes Studied?" -
UPSeis from Michigan Technological University
Includes a photograph and description of the first device used to detect earthquakes and an illustration showing how seismograms are generated.

"The Early History of Seismometry (to 1900)" by James Dewey and Perry Byerly, USGS National Earthquake Information Center
Series of "chapters" which detail the early development of instruments used to detect and measure earthquake activity.

Interpreting Seismograms

"How Do I Read a Seismogram" -
UPSeis from Michigan Technological University
Includes images to help you to learn to read seismograms.

"Seismometers, Seismographs, and Seismograms"
USGS Cascades Volcano Observatory

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Last updated: May 11, 2010

This project is supported, in part, by the National Science Foundation and the AGI Foundation. Opinions expressed are those of the authors and not necessarily those of the Foundation.