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Make Your Own Earthquake: What is a Seismometer?

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Abstract

Students will learn that a seismometer detects three components of motion and that a seismogram is the record of an earthquake. Prior to this activity, students should be introduced to the basics of earthquakes. Curriculum for this can be found at http://www.redcross.org/disaster/masters/ . This curriculum is designed for k-2, 3-5, and 6-8 grade levels. Other good activities can be found at http://www.dlese.org/ or http://web.ics.purdue.edu/~braile/.

Please view attachments for full activity, and scaling for K-5, and 6-12 lesson plans.

Make Your Own Earthquake

 

 

 

 

 

 

 

 

 

Learning Objectives and Standards

Links to the National Science Standards and to individual State Science Standards are available by using this link:

http://nees.org/education/for-teachers/k12-teachers#standards

Material List

QCN Demo installed on laptop

LCD projector or monitor

Internet access to view video

Slinky

Procedure

1. Begin with the computer on a level surface.

2. Let students observe the seismic sensor for a few minutes. Encourage them to jump   up and down or bang on the table with a fist or drop books.

3. Have students explain what they observe on the screen. What does each graph mean? What is the horizontal axis and the vertical axis? (You may want to avoid using x and y since the directions of the sensor are described by x, y, and z). Where on the graph is the time now? Why does the picture move to the left? Any ideas about the Earthquake Significance graph? What about the trigger line? Let students wonder about the Earthquake Significance for now.

4. Begin to lead students to think about what the purpose of the software is. What do you think this program is designed for? Why? The purpose of the Quake Catcher Network is to detect earthquakes and record the seismic activity on many internet-connected computers to rapidly detect earthquake activity.

5. Ask students if they have ever felt an earthquake. Ask for a few descriptions of what they felt. Use their experiences to introduce the Earthquake Simulation. Explain to the students that they are going to pretend that an earthquake occurs. Read the Earthquake Simulation Script three times.

Round 1. move in any direction Round 2. move up and down only Round 3. move side to side only

After wrapping up the Earthquake Simulation, show video clips of a real earthquake. Video from the 2001 Earthquake in Seattle, WA was captured by several security cameras and can be seen at http://www.classzone.com/books/earth_science/terc/content/visualizations/es1005/es1005page01.cfm?chapter_no=visualization or several on Youtube.com.com/books/earth_science/terc/content/visualizations/es1005/es1005page01.cfm?chapter_no=visualization or several on Youtube.com.

Earthquake Simulation Script

Imagine that you hear low, rumbling sounds. The noise is getting louder and louder, for just a few seconds. Then you feel a large shake. You feel like were thrown out of bed, or a truck just hit the side of a building.

The floor or ground is moving beneath you. You move up and down and side to side, shaking and mov- ing every which way. The building is creaking. The trees are swaying. Books fall from the shelves, lights swing, windows may break. Imagine what it feels like as all this chaos is going on. You try to get under your desk to protect yourself from falling and flying objects.

Then it stops. It is quiet. The ground is no longer moving. Everything is a mess.

Ask students how if felt. If they were scared, say that it is ok to feel that way. This is what happens during earthquakes. We build buildings today to withstand earthquakes. Also, we study them to understand how they occur. And with the QCN, we are trying to develop an early warning system for when earthquakes occur for safety reasons.

What direction did they move as the earthquake was occurring? Up and down? Side to side? Was the first jump the biggest and did they get smaller over time?

Repeat with all students going up and down. Then all students going side to side. Make these much shorter than the first.

Earthquake Review

Earthquakes happen because of a sudden slip on a fault in the earth�s surface where the rock on one side moves up, down, or sideways relative to the other side. An earthquake is felt as a sudden, rapid shaking on the surface of earth. This shaking can last a few seconds or even a few minutes. The motion causes waves that moves through Earth.

Earthquakes are detected with instruments that measure and record the seismic waves. In general, seis- mologists now use seismometers and digital recorders, rather than the older seismographs (drum of paper spinning with a needle) which are only used for show on TV when there is a big earthquake because the TV channels like to show them. The record or graph is called a seismogram.

6. There are a few kinds of waves generated by earthquakes. A good way to explain P- and S- waves is with a slinky. Have two students sit opposite each other with a slinky pulled taught across the floor between them.

When one student pushes their end of the slinky toward the other, it creates a wave like a P wave. When the student pushes the end of the slinky to the right or left, it creates a wave like an S wave.

7. Demonstrate how different motions of the computer are recorded by the sensor. Move the computer in the different directions as shown in the figure. X is the motion from left to right (east to west). Y is the direction from front to back (north to south) and z is the motion up and down (vertical component). Earthquake Significance is a calculated value based on the X, Y, and Z over the last minute. It helps distinguish noise from a real earthquake signal. distance, which is how the vertical component Z is measured.

Explanation for the Teacher: One way to think about the different directions is to image a boat floating at the surface floating at the surface of the ocean. It moves with the ocean waves, up and down, and side to side. The pitch of the boat is the angle from bow to stern (front to back), measured here as the Y component. The roll of the boat is the angle from port to starboard (left to right), measured here as the X component. The sensor measures angular rotation which is a bit more complex than just measuring a linear distance, which is how the vertical component Z is measured.

8. Bring groups of students up to the computer to experience the changing of the measured motion as they move the computer. This give each student a chance to experience this 3 component system of the motion themselves.

9. While the other students are at their desks, have them write a letter to a friend describing what they felt during the earthquake simulation. Rotate all the students through the experience to move the computer.

10. Ask students what they learned from their experience with moving the computer. How are the records similar for the computer and the letter that they wrote? What is the EQ Significance? How does that change?

What sources of error are there in the classroom? (doors slamming, table shaking, etc)

11. Describe the Quake Catcher Network and how the computer will always be running the program in the background to detect earthquakes. Discuss EQ Significance graph.

 

Explanation for the Teacher: Earthquake Significance

The Earthquake Significance is a calculated value based on the last 60 seconds to detect significant signals. It helps detect strong new vibrations measured by the laptop�s sensor. If EQ Sig is above some level, the laptop informs the QCN server that it has detected a new vibration. It sends the time, amplitudes (x, y, and z) and the EQ Sig. If many laptops tell the server there is a strong shaking all at once, we know it is an earthquake. The QCN server evaluates triggers from 100s to 1000s of laptops. If the QCN server suddenly receives more triggers than expected from a particular area, we know there is an earthquake. If only a few laptops produce triggers in an area, we know that it is probably people bumping their laptops. If successful, it may be possible for anyone participating to learn of a large earthquake before they feel it and take safety precautions.

Links and Resources

Cite this work

Researchers should cite this work as follows:

  • NEES EOT (2011), "Make Your Own Earthquake: What is a Seismometer? ," http://nees.org/resources/2790.

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