Are You Ready to Shake?

Earthquakes / Grades 9-12 / Earth Science, Physical Science




Focus Question

What can be done to reduce the vulnerability of coastal communities to the potential effects of earthquakes and their associated hazards?

Learning Objectives

Links to Overview Essays and Resources Useful for Student Research

http://oceanservice.noaa.gov/topics/coasts/assessment/

http://www.csc.noaa.gov/rvat/hazid.html

Materials

Audio/Visual Materials

None

Teaching Time

One or two 45-minute class periods, plus time for student research

Seating Arrangement

Groups of 3-4 students

Maximum Number of Students

30

Key Words

Natural hazard
Risk
Vulnerability
Earthquake
Tsunami
Landslide
Liquefaction
Subsidence
Secondary hazard

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Background Information

Almost half of the people living in the United States live near the coast. As the coastal population continues to grow, more people and property are threatened by natural hazards. Low-lying areas are particularly vulnerable, a fact that has been repeatedly underscored in recent years:

These disasters emphasize the importance finding more effective ways to reduce the negative environmental, social, and economic impacts of natural hazards on coastal communities. To assist these efforts, NOAA’s National Ocean Service (NOS) provides essential information on natural hazards to government agencies and members of the general public concerned with lowering the risks associated with natural hazards. This information includes training, methods for assessing vulnerability to natural hazards, and tools that can be used to forecast threats such as floods and harmful algal blooms.

Ports and harbors are the focus of particular concern, because their location makes them vulnerable to a wide range of hazards. Moreover, if ports and harbors are built on fill material or soft natural material, or are surrounded by steep slopes, they are at risk of being damaged by earthquakes, tsunamis, and landslides. Earthquakes are associated with movement of the tectonic plates that make up the Earth’s crust. The outer shell of the Earth (called the lithosphere) consists of about a dozen large plates of rock (called tectonic plates) that move several centimeters per year relative to each other. These plates consist of a crust about 5 km thick, and the upper 60 - 75 km of the Earth’s mantle. The plates that make up the lithosphere move on a hot flowing mantle layer called the asthenosphere, which is several hundred kilometers thick. Heat within the asthenosphere creates convection currents (similar to the currents that can be seen if food coloring is added to a heated container of water). These convection currents cause the tectonic plates to move. Plates may slide horizontally past each other at transform plate boundaries. The motion of the plates rubbing against each other sets up huge stresses that can cause portions of the rock to break, resulting in earthquakes. Places where these breaks occur are called faults. A well-known example of a transform plate boundary is the San Andreas fault in California.

Where tectonic plates move apart (for example, along the mid-ocean ridge in the middle of the Atlantic Ocean) a rift is formed, which allows magma (molten rock) to escape from deep within the Earth and harden into solid rock known as basalt. Where tectonic plates come together, one plate may descend beneath the other in a process called subduction. This process generates high temperatures and pressures that can lead to strong earthquakes and explosive volcanic eruptions, such as the Mount St. Helens eruption which resulted from subduction of the Juan de Fuca tectonic plate beneath the North American tectonic plate. The Sumatra-Andaman earthquake was caused by subduction of the India Plate beneath the Burma Plate.

In this lesson, students will investigate hazards associated with earthquakes, and some of the activities that can mitigate these hazards.

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Learning Procedure

  1. To prepare for this lesson:
  1. Briefly review the issue of coastal hazards. You may want to show some headlines and images from the 2004 Indian Ocean earthquake (your school or community library probably has back issues of weekly news magazines that could be used for this). Discuss the types of natural hazards that may pose a risk to coastal communities. The list should include hurricanes, floods, tsunamis, and earthquakes. Be sure students understand that increasing population in coastal communities means that an increasing number of people and their property are potentially threatened by these hazards.
  2. Tell students that this lesson will focus on hazards associated with earthquakes. Briefly review the relationship between earthquakes and movement of Earth’s tectonic plates. Compare and contrast hazards associated with hurricanes and those associated with earthquakes. One of the most striking differences is that specific earthquake events can happen with little or no warning, while hurricanes are rarely a surprise (though this has only been true since modern meteorological instruments and techniques have become available). On the other hand, the relationship between earthquakes and tectonic activity means that the relative risk of different geographic areas can be predicted fairly well.

Provide each student or student group with a copy of the “Are You Ready to Shake?” Worksheet, and say that their assignment is to do the research needed to prepare a written report that includes answers to questions on the Worksheet. Assign each group one of the following hazards for which they are to describe potential mitigation activities:

  1. Discuss students’ answers to their worksheet Step 1. The following points should be included:
  1. Have each group present mitigation options identified for their assigned hazard. Students should realize that while it is commonly assumed that “there is nothing we can do about earthquakes,” the reality is that there are many things that can be done to reduce vulnerability to earthquakes and their associated hazards.

    Options for mitigating earthquake hazards include:

Options for mitigating landslide hazards include:

Options for mitigating liquefaction hazards include:

Options for mitigating subsidence hazards include:

Options for mitigating secondary hazards include:

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The Bridge Connection

The Bridge is a growing collection online marine education resources. It provides educators with a convenient source of useful information on global, national, and regional marine science topics. Educators and scientists review sites selected for the Bridge to insure that they are accurate and current.

http://www.vims.edu/bridge/ – In the navigation menu on the left, click on “Ocean Science Topics,” then “Physics” for links to information and activities related to tsunamis and earthquakes.

The “Me” Connection

Have students write a brief essay describing a personal disaster preparedness plan. If their own community is not susceptible to earthquakes or tsunamis, you may want to suggest more likely disaster scenarios (e.g., a wrecked train leaking hazardous chemicals; severe blizzard; flooding caused by unusually heavy rains).

Extensions

Have students prepare personal disaster preparedness plans, including provisions for 3-day self-sufficiency and communications/rendezvous plans with family members.

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Resources

http://webqa.csc.noaa.gov/products/tsunamis/index.htm – NOAA's National Ocean Service “Protecting Our Ports and Harbors” Web site

http://earthquake.usgs.gov/ – The U.S. Geological Survey’s Earthquake Hazards Program Web site

National Science Education Standards

Content Standard B: Physical Science

Content Standard D: Earth and Space Science

Content Standard E: Science and Technology

Content Standard F: Science in Personal and Social Perspectives

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Ocean Literacy Essential Principles and Fundamental Concepts

Essential Principle 1. The Earth has one big ocean with many features.

Essential Principle 2. The ocean and life in the ocean shape the features of the Earth.

Essential Principle 6. The ocean and humans are inextricably interconnected.

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Are You Ready To Shake

Student Worksheet

This Worksheet is intended to help you find out more about hazards associated with earthquakes. All of the information needed to complete this worksheet can be found at NOAA's National Ocean Service “Protecting Our Ports and Harbors” Web site: http://webqa.csc.noaa.gov/products/tsunamis/index.htm, and the U.S. Geological Survey’s Earthquake Hazards Program Web site: http://earthquake.usgs.gov/.

1. Define:

2. Identify mitigation options for one of the following hazards assigned by your teacher:

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