Investigating Factors That Affect Tsunami Inundation

Bonnie Magura (Portland Public Schools), Roger Groom (Mt Tabor Middle School), and CEETEP (Cascadia EarthScope Earthquake and Tsunami Education Program)

Summary

Learners modify elements of a tsunami wave tank to investigate the affect that near-coast bathymetry (submarine topography) and coastal landforms have on how far a tsunami can travel inland. Damaging tsunami are most commonly produced by subduction zone earthquakes, such as those that occur in Alaska.

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Context

Audience

This activity could be done with introductory geoscience learners in secondary school or early college. It can also work for informal education or public outreach venues as a demonstration or interactive.

Skills and concepts that students must have mastered

Learners should know what tsunami are and some ways they can be triggered. They should also have experience with doing inquiry investigations and using the scientific method.

How the activity is situated in the course

This should probably come later in a unit on earthquakes and tsunami after students already know something about these geohazards. Suggestions are given below in the references for other resources and activities on this topic.

Goals

Content/concepts goals for this activity

Learners will be able to:
  • Identify topographic or other factors that affect tsunami inundation

Higher order thinking skills goals for this activity

  • Conduct an experiment related to tsunami inundation
    • Form a Question or Hypothesis,
    • Design an Investigation around the topic,
    • Collect and Present Data, and
    • Analyze and Interpret their Results.

Other skills goals for this activity

  • Working in groups
  • Using physical models

Description and Teaching Materials

Many low-lying coastal areas around the globe are at risk of tsunami. Subduction zones have the greatest hazard as the can have large locally-generated ones from large-magnitude earthquakes. However, even if passive margins there can be hazard from landslide or volcano-generated tsunami or distant tsunami that travel thousands of kilometers. This activity gives students the chance to practice science inquiry, while learning more about how differences in the shape of a coast and lead to some areas have greater inundation. It can underpin subsequent activities on community resilience planning.

Part 1 Hypothesis and Design

Students decide which variables to investigate and design the tsunami inundation model to test their hypothesis. You can lead a class brainstorming session or present options from the possible variables list in the educator guide document.

Part Two: Collect and Analyze Data

Students run a series of experiments to measure changes in inundation with changed variables. They collect, organize, and display sufficient data in both table form and in sketches.

Part Three: Conclusion

Students summarize findings and use them to evaluate the initial hypothesis related to tsunami inundation from students' own groups and others.

Teaching Materials

See attached file for educator notes, NGSS alignment, student worksheet, and suggested grading scheme.


Teaching Notes and Tips

  • See above educator notes
  • Regionally damaging tsunami are most commonly produced by subduction zone earthquakes but locally very damaging tsunami can occur due to landslides or volcanic eruptions. In Alaskan fjords the shaking during an earthquake can cause submarine landslides that generate tsunami, which reach shore while earthquake shaking is still going on. You could experiment with adding a landslide variable to the wave tank experiments by dropping in a packet of gravel rather than using the paddle to make the wave.
  • Once students understand more about factors that affect tsunami inundation, they are ready to go on to other activities that highlight preparedness and resilience. The ANGLE Mitigation and Preparedness activity collection has a range of options. Most appropriate might be Earthquake Hazard Inventory & Mitigation Planning or Tsunami Vertical Evacuation Structures.

Assessment

The exercise worksheet serves as the summative assessment for the activity. The answers are short but open ended so the instructor should develop a simple couple-point scale for evaluating the completeness of each answer. Suggestions are provided in the answer key/rubric version of the student worksheet.

Alternatively, if the activity is being used for a demonstration or informal interactive activity, questions and discussions with learners can help the presenter gauge the level of understanding and to address misconceptions.

References and Resources