Earthquake Magnitude - Linking Earthquake Magnitude and Intensity

Eric Baer
Highline Community College
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Initial Publication Date: July 5, 2007


An activity that helps students link earthquake magnitude and intensity.

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This is used in an introductory geoscience course for non-majors with a sizable seismology component.
Designed for an introductory geology course

Skills and concepts that students must have mastered

Knowledge of some basic vocabulary, such as magnitude and acceleration.

How the activity is situated in the course

It is part of a sequence of activities linking earthquakes and damage.


Content/concepts goals for this activity

Students will link earthquake magnitude and acceleration and then link acceleration and intensity.

Higher order thinking skills goals for this activity

Other skills goals for this activity

Calculations and use of formulas

Description of the activity/assignment

Earthquake magnitude is commonly used to represent the size of an earthquake. However, most people want to understand how much impact or damage earthquakes do. These two concepts are linked by shaking. Earthquake magnitude can be measured in a variety of ways, most commonly moment magnitude or Richter magnitude. Shaking is measured in units of acceleration, (often a percentage of g). Damage or intensity can be measured by the modified Mercalli intensity (MMI) scale.
In this activity, students will model earthquakes of various magnitudes to determine the amount of shaking that these quakes will cause. They will then convert the shaking to modified Mercalli intensity and generate an isoseismal map for a M8 and M6 earthquake.
Uses geophysics to solve problems in other fields
Addresses student misconceptions

Determining whether students have met the goals

I grade what they submit!

More information about assessment tools and techniques.

Teaching materials and tips

Other Materials

Supporting references/URLs

Donovan, N.C., (1973). A statistical evaluation of strong motion data including the Feb. 9,1971, San Fernando earthquake. Proc., 5WCEE, Rome, Italy, 1: 1252-1261.

Trifunac, M. D., and A. G. Brady (1975). On the correlation of seismic intensity scales with the peaks of recorded ground motion, Bull. Seism. Soc. Am. 65, 139-162
Wald, D. J., T. Heaton, H. Kanamori, P. Maechling, and V. Quitoriano (1999a). Research and Development of TriNet "Shake" Maps, Earthquake Spectra, 15.

Wald, D.J., V. Quitoriano, T.H. Heaton, and H. Kanamori (1999b). Relationships between peak ground acceleration, peak ground velocity, and modified Mercalli intensity in California, Earthq. Spectra 15, 557-564.