# Earthquake Intensity

#### Summary

When describing the severity of an earthquake at any given location, several measures are needed. The amount of energy released in the earthquake is reported as the magnitude, measured quantitatively using the Moment Magnitude scale. The energy released in an earthquake is a static number, regardless of how close you are to the epicenter. In contrast, the impact of the earthquake, in terms of shaking and damage caused, depends greatly on how close you are to the epicenter. The shaking and damage caused by an earthquake is termed the intensity, which is measured qualitatively, using the Modified Mercalli Intensity (MMI) scale. In this introductory lesson, learners compare ShakeMaps between earthquakes in the same location but different magnitudes, and earthquakes of the same magnitude but different depths, to acquaint learners to the fundamental controls on intensity of shaking felt during an event: magnitude and distance from the earthquake source.

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## Context

#### Audience

This activity can be done with introductory geoscience learners from late elementary through secondary and even early college.

#### Skills and concepts that students must have mastered

Prior experience with earthquake magnitude and how it is measured would be helpful preparation. The activity Pasta Quake can be a good way to learn this.

#### How the activity is situated in the course

Appropriate to include fairly early when learning about earthquakes. In most cases this would follow some introduction to plate tectonics so learners are familiar with why earthquakes happen.

## Goals

#### Content/concepts goals for this activity

• Distinguish earthquake magnitude and intensity
• Understand how earthquake intensity varies with changes in magnitude or distance to the hypocenter

#### Higher order thinking skills goals for this activity

• Analysis of data
• Formulation of hypotheses

#### Other skills goals for this activity

• Interpreting spatial information
• Considering controlled variables

## Description and Teaching Materials

Students compare ShakeMaps between earthquakes in the same location but different magnitudes, and earthquakes of the same magnitude but different depths, then discuss the fundamental controls on intensity of shaking felt during an event: magnitude and distance from the earthquake source.

#### Activity

See attached file for instructor notes, NGSS alignment, and links to supporting resources.
Earthquake Intensity Activity (Acrobat (PDF) 7.5MB Feb16 22)

## Teaching Notes and Tips

• The map scales are different, so instructors should monitor how learners are comparing the spatial distribution of shaking intensity (ensure they are interpreting the scales and map distances correctly)
• Instructors can obtain ShakeMaps from other earthquakes at the United States Geological Survey webpage https://earthquake.usgs.gov/data/shakemap/

## Assessment

Students describe the differences between magnitude and intensity based on the examples.