1. The Big One - Logistics

Time
5-10 min earthquake demo
35-45 min computer research
45-50 min present research, plot on large map, look for patterns

Grouping
Individual

Materials

• 2 pieces of Plexiglas
• scotch tape
• Optional: Monopoly houses and game pieces
• Computers with internet access
• Copy of “The Big One” handout for each student
• Copy of the “Big Quake Dates” sheet, cut into strips with one time period on each strip
• Large world map, preferably laminated or coated so that removable sticky dots can be easily applied then removed after the activity.
• 1 package 1/4” to 1/2” removable color dots (available in most stationary stores and drug stores for labeling maps and documents, each package usually contains 4 colors of dots: red, yellow, green and blue)

Setting
Computer lab

1. The Big One - Background

Earthquake epicenters 1963-1998: Image courtesy of NASA.
Teacher Background
An earthquake is the shaking that results from stored energy in the Earth that is suddenly released. When an earthquake occurs, seismic waves travel through the earth and can be measured by a seismograph (see the background section of the Earthquake Fingerprints activity for more information).

Most earthquakes (particularly the largest ones) occur at the boundary between 2 tectonic plates. Briefly, the Earth’s crust is composed of several large plates that are in slow but constant motion across the surface of the planet (see the background section of the Plate Patterns activity for more information). The boundary between two plates is the fault. There are many types of faults that push past one another in different ways – strike-slip (where the plates slide past each other like in the demo), normal and thrust (where one plate slides up relative to the other.

I demonstrate this concept with 2 Plexiglas sheets laid side by side on the table. I tape the junction with scotch tape. The 2 pieces of Plexiglas represent 2 of Earth’s tectonic plates; the gap between them represents the fault. The scotch tape represents the friction between the plates – all the soil and rock at the junction that prevents the plates from sliding past one another freely. Then slowly I push the plates past each other in opposite directions, one pushing away from me, one pulling towards me. A bunch of energy is stored and then suddenly, the tape fails and the plates jump apart in a sudden release of energy. Put a couple of Monopoly houses on each piece of Plexiglas and the point is driven home.

The activity that follows has students conducting research on historically significant earthquakes around the world using the USGS Earthquake Archive. Each student is assigned a time frame to research and picks 10 earthquakes in that time frame to record information about. There are around 36 time frames available. The following day, they share details about one of the earthquakes they researched and plot each of the 10 earthquakes on a large world map in the classroom.

What is revealed is a very uneven distribution of earthquakes around the world. Almost all the earthquakes cluster along plate boundaries where plates are colliding (convergent boundaries) or sliding past one another (transform boundaries) although earthquakes occur at divergent boundaries as well.

An alternative way to achieve the same result is to track and plot the locations of earthquakes around the world day by day for several weeks/months until a pattern emerges. The USGS earthquake center provides a daily list of earthquake occurrences on their website with latitude, longitude, and magnitude information.

Student Prerequisites
None

1. The Big One - Getting Ready

Getting Ready

1. Reserve the computer lab.
2. Make copies of “The Big One” handout.
3. Make one copy of the “Big Quake Dates” handout per class (possibly on colored paper or cardstock paper) and cut it into strips with one time period per strip.
4. Laminate the map if desired and hang it up near the front of the classroom.
5. Set out remaining materials: Plexiglas, scotch tape, Monopoly houses, and color dots.

1. The Big One - Lesson Plan

Lesson Plan
What is an earthquake demo:

1. Ask the students what they know about earthquakes. You can list their responses on the board.
2. Tell students that you are going to demonstrate what causes an earthquake. Set the 2 piece of Plexiglas on the table side by side. Describe how the gap between the pieces represent a “fault” a crack on the Earth’s surface that is susceptible to suddenly giving way and moving. Don’t talk about tectonic plates yet since the students will soon discover their existence on their own! Simply refer to the pieces of Plexiglas as pieces of land with a fault in between.
3. Lay a 6 inch piece of scotch tape along the fault line. Describe how the tape represents the rocks and soil along the fault that help hold the pieces together. Make the junction secure but don’t work too hard at taping the pieces together or you will have to push very hard to get the fault to slip.
4. Optional: decorate the surfaces with Monopoly houses and pieces.
5. Slowly and steadily push one piece of Plexiglas away from you while pulling the other piece towards you. Eventually the tape will give way and suddenly break free. Monopoly pieces may scatter.
6. Discuss with your students what they observed, paying particular attention to the energy that is stored and suddenly released.

Computer research:

1. Pass out the handouts and go over their assignment.
2. Allow each student to pick one slip of paper with a time frame on it.
3. Give students 35-45 minutes to complete their research on the website.
4. Remind students that they should mark the location of each earthquake on their list on the map for homework if they didn’t finish it in class.

Plotting earthquake locations:

1. Ask students to get out their handouts from the previous day.
2. Explain the procedure for the day. Each student will share details about one of the earthquakes they researched (preferably the one they used as an answer to question #4 on their handout). Then they will be given some color dots to plot the location of each of their earthquakes on the large map. Different colors will represent earthquakes of different magnitudes (red is not used here since it will represent volcanic activity in the Plate Patterns activity).

Magnitude	Color
5.9 or lower	Blue
6.0-7.9	Green
Over 8.0	Yellow

3. One by one, have students come up to the front of the room to present their earthquake. They should describe the date it occurred, the magnitude, the location, and the 3 facts they learned about it.
4. After a student finishes, give him/her sticky dots to plot their earthquakes on the map. While they plot their information, another student can come up and describe their research. Regulate the flow so that no more than 2-3 students are plotting their data on the map at one time.
5. When all students have gone and all the data is plotted on the map, discuss any patterns you see on the map as a class. The goal here is really to have the students relate what they learned about the causes of earthquakes from the demonstration to what they are seeing on the map. The faults are the lines of earthquakes. The large blank areas are like the pieces of Plexiglas and are called tectonic plates. Some questions to consider include:
• Where are we? How many major earthquakes have occurred near us?
• Are the earthquakes evenly distributed across the map?
• What are the most active earthquake areas in the world?
• What do the clusters of earthquakes look like? Do they cluster in patches or in lines?
• Look at the magnitude information. Where do the biggest earthquakes take place?
• Think back to the demonstration at the beginning of this lesson. Remember how earthquakes are caused when energy is suddenly released along a fault. Where are the big faults on the planet (think of it as an abstract dot-to-dot drawing)?
• The Plexiglas represented large pieces of land bordered by faults. Geologists call these large pieces of land tectonic plates. Where are the tectonic plates? How can we use the earthquake data to find the edges of the plates?
• Do ALL earthquakes happen at the edges of plates? (No.) What are some of the exceptions that don’t seem to fit the general pattern.
6. Optional: Have students copy the patterns you discover onto their personal maps on the handout – defining the plate boundaries and faults in between.

1. The Big One - Assessment

Assessment

1. Collect the handouts.
2. Ask students to explain what causes an earthquake. Include both a short paragraph and a labeled picture.

Going Further

1. Add information about earthquake depth to the student tables and the class map. The deepest earthquakes tend to take place on or near subduction zones.
2. See if the location of volcanoes also matches the plate boundary lines. Add data about the mid-ocean ridges and identify plate boundary lines. See the Plate Patterns activity for details.
3. Look at the earthquakes that didn’t line up on a plate boundary. What is happening there? Investigate the causes of earthquakes that didn’t occur on a plate boundary.
4. Play with the “This Dynamic Planet” map which allows you to select certain types of data to display on a dynamically generated map. Some of the data types you can select are volcanoes, earthquakes of different magnitudes, impact craters, plate boundaries, latitude/longitude grids and more.

1. The Big One - Sources and Standards

Sources
The idea came from Eric Muller’s activity Locating Earthquake Epicenters. His lesson suggests plotting daily earthquake data but I wasn’t able to spend a few minutes a day on that. Instead I modified Eric’s activity to fit in a single class period.

For resources and additional background information on plate tectonics, see the sources section of the Plate Patterns lesson.

Standards
Grade 6
Plate Tectonics and Earth's Structure
1. Plate tectonics accounts for important features of Earth's surface and major geologic events. As a basis for understanding this concept:
a. Students know evidence of plate tectonics is derived from the fit of the continents; the location of earthquakes, volcanoes, and midocean ridges; and the distribution of fossils, rock types, and ancient climatic zones.
d. Students know that earthquakes are sudden motions along breaks in the crust called faults and that volcanoes and fissures are locations where magma reaches the surface.
e. Students know major geologic events, such as earthquakes, volcanic eruptions, and mountain building, result from plate motions.

Shaping Earth's Surface
2. Topography is reshaped by the weathering of rock and soil and by the transportation and deposition of sediment. As a basis for understanding this concept:
d. Students know earthquakes, volcanic eruptions, landslides, and floods change human and wildlife habitats.

Investigation and Experimentation
7. Scientific progress is made by asking meaningful questions and conducting careful investigations. As a basis for understanding this concept and addressing the content in the other three strands, students should develop their own questions and perform investigations. Students will:
f. Read a topographic map and a geologic map for evidence provided on the maps and construct and interpret a simple scale map.

Grades 9-12 Earth Science
Dynamic Earth Processes
3. Plate tectonics operating over geologic time has changed the patterns of land, sea, and mountains on Earth's surface. As the basis for understanding this concept:
d. Students know why and how earthquakes occur and the scales used to measure their intensity and magnitude.