National Teachers Enhancement Network: Lesson Plan

Lesson Plan: Earthquake Epicenters and Magnitudes
Subject: Earth and Space Science / Geosphere / Earthquake Epicenters
Classtime: 120 minutes
Grade Level: 4-12

Materials/Technology:

computers with Internet access
color printer
work sheets for each student
names of earthquake locations on pieces of paper-one per student

Safety, Handling, Disposal:
When using the Internet, close supervision is strongly recommended. Inappropriate sites are easily accessed, either by mistake or on purpose.

Learner Outcomes:
Students should be able to:

Define and use vocabulary.
Use seismograms to find Amplitude and S-P intervals.
Use a time-travel graph to determine distance to the epicenter of an earthquake.
Understand how triangulation is used to find the location of the epicenter of an earthquake.
Determine the Richter Magnitude of an earthquake.
Interpret graphs and apply interpretation to solve problems given at the web site.

Problem/Purpose:
At an on-line interactive earthquake simulation web site, students will use tools and methods that scientists use to determine important information about an earthquake.

Background/Inquiry:
This activity can be used as an introduction to Epicenters and Earthquake Magnitudes or as an activity to reinforce the two topics after they have been introduced. The students should know what an earthquake is and have a general idea of what causes them. Students should also be familiar with getting information from graphs.

About Earthquakes:

The outward transfer of Earth's internal heat drives convection circulation in the mantle that propels the plates comprising Earth's surface across the face of the globe.

This on-line interactive activity will encourage students to learn and understand about the internal energy that the Earth possesses. They will see the connection of the internal energy of the Earth and how it drives changes in the outward appearance of the Earth's surface. The time intervals between major quakes in one area will help reinforce the slowness of many changes, but also help to illuminate the speed with which small sudden changes may take place. These investigations will also show where many of the interactions in the Earth's crust take place-- the plate margins.

This activity assumes that the students have a basic knowledge of computer use, terminology, Internet browsers and the Internet. NSTA teaching standards (Teaching Standard D) recommend educators "Make the available science tools, materials, media, and technological resource accessible to students." This activity provides an opportunity to use some of the new technology on the Internet and will also make the students more familiar with some of the tools that a scientist would use. It gives students the chance to interpret actual data, somewhat simplified, that a seismologist would use in determining the epicenter and magnitude of an earthquake.

Hypothesis: N/A

Procedure:
Advanced teacher prep -

It is recommended that instructors work through this activity prior to teaching the lesson to become familiar with the required reading, graph use, and terminology. Check carefully to see if your students can handle getting the information from the graphs. If it looks too difficult for students to grasp, devote some time to teaching this part of the exercise in isolation before getting logged on to the site.

Have the earthquake locations written on slips of paper to facilitate assignment of earthquake locations to the class. Location names are San Francisco area; Southern California; Japan region; Mexico. Also, make sure to have one work sheet per student ready. *Note: The work sheets will keep all of the students a little more focused, and not just the ones that are using the web. If class time expires and worksheet is incomplete, log-on during the next available period, insert data from the worksheet, and complete the task.

Student procedures -

Distribute earthquake-site assignments. (Pick out of a hat? Devise groupings?)
Distribute work-sheet pages to students. Give a brief overview of the site. Have students skim-read the work sheets to get the general picture of the requirements of the simulation. Answer student questions.
Take the students to the computer lab and log-on to the web site.
Students work through the activity and fill out the worksheets. *Note: The students will receive a certificate upon completion of the activity.

Work Sheets
Epicenters and Magnitudes
Name______________________________ Period________ Date_________

In the location bar of your browser, type the following address, or find the virtual earthquake site in the bookmarks, which ever one your instructor requests. http://64.239.9.13/VirtualEarthquake

Read the paragraphs explaining what you will be doing in this activity. Please note that you must make your measurements very carefully to receive a certificate at the end of the activity. When you have finished reading, click on [Execute Virtual Earthquake].

Here is a list of vocabulary that you need to define as you go through the pages of this activity. You will not get all of the definitions from the first page. Don't forget to fill in the definitions as you find them.

Amplitude-

Arrival time-

Epicenter-

Focus-

Magnitude-

Richter Magnitude Scale-

S-P Interval-

Seismogram-

Seismograph-

Read through this first page and answer the following questions.

What is an earthquake?

What are seismic waves?

What types of seismic waves are mentioned?

How are these waves different?

What information do you need to find the epicenter of an earthquake?

What is the name of the process that is used to find the epicenter?

Make sure that you can see how to get the numbers from the seismogram in the example. If you do not see how to do this, please ask your partners or your teacher. When confident getting the numbers from the seismograms, proceed to your location that has had a major earthquake. You can see a list of these four places at the bottom of the page. CLICK on the button in front of your location and then CLICK on the [SUBMIT CHOICE] button to go to the next page.

Read the descriptions that you see. Look at the seismogram and answer the following questions.

What type of seismic wave arrives first?____________________________________________________

How many seconds does each line on the graph represent?______________________________________

Explain how you can tell this from the graph._________________________________________________

What is meant by the 'S-P' interval?_______________________________________________________

When you are sure that you can find the S-P Interval you can CLICK on [View Seismograms].

Use the seismograms to answer the following questions.

What is the arrival time of the P-wave? Station 1_____ Station 2_____ Station 3_____

What is the arrival time of the S-wave? Station 1_____ Station 2_____ Station 3_____

What are the S-P Intervals? Station 1_____ Station 2_____ Station 3_____

Enter the values for the S-P Intervals under each Seismogram. When you have these entered, CLICK on [Convert S-P intervals].

Read the descriptions and practice using the time travel graph. Check with your teacher to see if you are using the graph correctly. When you are ready, use the large time-travel graph to find the distance that the waves traveled for each of your three stations. Make sure that you estimate the value if it is not directly on a line. Answer the following questions and type in the distance values that you get.

What is the value of each line of distance on the graph?________________________________________

How can you tell?

What are your distances? Station 1_____ Station 2_____ Station 3_____

What are the units for distance on the graph?

When you are sure of your distance values, CLICK on [Find Epicenter].

Look at the map of the epicenter.

Do your three circles intersect in exactly the same spot?

Should they meet in one place?_____ Why?

If the button at the bottom of the page reads [Re-measure S-P Interval], CLICK on that button and get better estimates of the times and distances that you have chosen and re-submit them.

When the three circles meet at one spot, what is that spot called?_________________________________

What factors may affect the accuracy of this method? _________________________________________

When you have answered these questions and gotten your circles to meet, CLICK on [Compute Richter Magnitude].

How big does an earthquake measured on the Richter scale have to be to be felt by people?

How would you describe maximum amplitude?______________________________________________

Can the maximum amplitude be below the zero line as well as above it? ___________________________

CLICK on [Go to Next Page].

What magnitude is a standard Richter earthquake?

How much amplitude does a "Standard" earthquake have?

If the Richter magnitude goes from 3 to 4, by how many mm does the maximum amplitude increase on the seismogram?

CLICK on [Go to Next Page].

Read the directions and determine the maximum amplitude for each of your stations. Remember that maximum amplitude can be above or below the zero line.

How much is each horizontal line worth for the amplitude?_____________________________________

What is the maximum amplitude for each of your stations? Don't forget to estimate between lines.

Station1_____ Station 2_____ Station 3_____

When you are sure of your values and you have typed them in, CLICK on [Submit to Nomogram].

View the nomogram and estimate the Richter magnitude for your earthquake.

What is your value?______________ Type in your value and CLICK on [Confirm Magnitude].

If your Richter magnitude is correct, you will get a message congratulating you. If it is incorrect, you will have to re-measure and re-enter your figures.

After successfully completing the exercise, select the "Enter Your Name" box and click. Type the names of all of the people in your group and your teacher's name in the space indicated. CLICK on [Get Certificate]. Select the print button in your web browser to print the certificate. Make sure you print one for everyone in your group.

End of worksheet / instructions.

Results/Analysis:
Check maps to see if all earthquakes are properly located. The completed worksheets submitted by students. The award certificate printout indicates successful completion of the task and must be attached to the worksheets.

*Note: Instructors could also require that the S-P Interval circles (meeting in one spot to show the epicenter of the earthquake) be printed to further verify work completion.

Conclusions:
Using seismograms at separate stations, it is possible to locate the epicenter of an earthquake. This procedure utilizes S-P Intervals, triangulation concepts, time travel graphs, amplitude and nomograms to ascertain the location.

Assessments:

The work sheets are a way to grade the student's completion of the problem. If you break the problem down into parts and assign 1 point to each question, then you get a 43 point total:

9 vocabulary definitions
6 first-page questions
6 first-page questions
4 seismogram questions
9 S-P wave questions (3 questions and 3 answers per question)
6 distance questions (1 question has 3 answers)
2 epicenter questions
3 Richter magnitude questions
4 maximum amplitude questions (1 question has 3 answers)
1 nomogram question

The worksheets are not a totally reliable measure for knowledge as the students will be sharing information back and forth and it is possible that some students might copy answers off of other students.

To further assess knowledge, have students use the work sheets as a study guide and test them on the major concepts.

Possible Assessment Questions: What is an Earthquake? What information do you need to get to find the Epicenter of an earthquake? Explain the process that is used to find the epicenter of an earthquake. What are earthquakes indicative of?

Applied Knowledge/Skill: Have students research other earthquakes and create their own "virtual" earthquake challenge by compiling seismograms and creating an exercise similar to the one that they worked through at the web site.

Reflections:
Share your thoughts on this lesson with the NTEN team.

Please send an e-mail to Patti Harrison.

Extensions: This extension will allow students to explore the effects of earthquakes in the context of pictures, monetary loses and eye witness accounts. Go to the Richter Magnitude Confirmation page (the last one); you will see a link that says "more info". Click on this to get to a page that will allow students to find more information about the earthquakes that they have just been working with to find the epicenters and magnitudes for. The students can use these links to gather information and write a report on their assigned earthquakes. It would be to write one to three typed pages just from these links. Some of the links provide very good pictures for the students to view.

References/Resources:
URLs used:Virtual Earthquake Site.
http://64.239.9.13/VirtualEarthquake

Credits
Contributing Teacher: Jeffrey Greenfield
NTEN Course: MATH 580: Internet-Based K-14 Earth System Science
Instructor: Jerry Nelson
Developing Team:
T.L. Buck Buchanan, Patti Harrison, Don Samuelson, John Usher, Don Wilson
HTML Programmers: Tyson N. Trebesch, Ryan Huddleston, Ken Eklund, Ching-Kwong Chia

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