Earthquake Hazard Maps & Liquefaction: Alaska emphasis
Ground shaking is the primary cause of earthquake damage to man-made structures. This exercise combines three related activities on the topic of shaking-induced ground instability: a ground shaking amplification demonstration, a seismic landslides demonstration, and a liquefaction experiment. The amplitude of ground shaking is affected by the type of near-surface rocks and soil. Earthquake ground shaking can cause even gently sloping areas to slide when those same areas would be stable under normal conditions. Liquefaction is a phenomenon where water-saturated sand and silt take on the characteristics of a dense liquid during the intense ground shaking of an earthquake and deform. Includes Alaska and San Francisco examples.
Skills and concepts that students must have mastered
Learners should know what earthquakes and earthquake waves are.
How the activity is situated in the course
This should probably come later in a unit on earthquakes, when the topic moves from understanding what earthquakes are to how they affect our society. This is a needed intermediate step to considering earthquake mitigation and preparedness.
Content/concepts goals for this activity
Learner are able to:
- Describe why different near-surface rocks and soil can lead to different levels of building damage during an earthquake
- Explain how shaking can lead to landslides
- Experiment with different soil water contents and observe liquefaction differences
Higher order thinking skills goals for this activity
Analyze experimental results and use the results to justify how water content impacts hazard to buildings.
Other skills goals for this activity
- Working in groups
- Using physical models
Description and Teaching Materials
See attached file for educator notes, NGSS alignment, links to supporting resources, student exercise, and answer key.
Earthquake Hazard Maps and Liquefaction Activities (Alaska emphasis) (Acrobat (PDF) 1.6MB Sep11 22)
The same basic suite of activities but with a Pacific Northwest USA emphasis was done by the Cascadia EarthScope Earthquake and Tsunami Education Program (CEETEP)
Teaching Notes and Tips
A number of materials are needed for these demonstrations and activities. See above educator notes.
The student exercise 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. 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.