Teach the Earth > Geophysics > Teaching Activities > Earthquake Magnitude - Linking Earthquake Magnitude and Intensity

# Earthquake Magnitude - Linking Earthquake Magnitude and Intensity

Eric Baer
,
Highline Community College
Author Profile

This activity has benefited from input from faculty educators beyond the author through a review and suggestion process. This review took place as a part of a faculty professional development workshop where groups of faculty reviewed each others' activities and offered feedback and ideas for improvements. To learn more about the process On the Cutting Edge uses for activity review, see http://serc.carleton.edu/NAGTWorkshops/review.html.

#### Summary

An activity that helps students link earthquake magnitude and intensity.

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## Context

#### Audience

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.

## Goals

#### Content/concepts goals for this activity

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

#### 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

## 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.