Soil Liquefaction and Earthquakes

Students investigate how different soil types - sand, peat, and topsoil - respond to shaking when saturated with water. By placing a model “house” on each soil type and simulating earthquake motion, they observe liquefaction effects and determine which soils provide the most stability.

1. Form a hypothesis about which soil type will resist liquefaction best.
2. Fill three shoebox-sized containers two-thirds full, one with sand, one with topsoil, and one with peat.
3. Build a model “house” from Lego or other construction materials (about 8 cm x 10 cm).
4. Add 1 liter of water to the first soil container (topsoil).
5. Place the Lego house on top of the soil, then set the container inside a larger bin to allow shaking.
6. Measure the height of the house from the soil surface to the roofline.
7. With a partner, shake the larger bin side to side for 40 seconds without lifting it off the surface.
8. Observe how the soil and house behave during and after shaking.
9. Re-measure the house height and note any tilting, sinking, or shifting.
10. Repeat twice more for the same soil, then test sand and peat in the same way.
11. Record results in a data table and calculate averages.

Liquefaction In Action - GeoscienceAustralia:

Demonstrate Liquefaction | Shaky Sediments - Science Snack Activity - Exploratorium Teacher Institute:

📄 Liquefaction - Earth Science Week: https://www.earthsciweek.org/resources/classroom-activities/liquefaction/

• Use houses of different weights to test whether heavier loads affect sinking.
• Change the amount of water added to see how saturation influences liquefaction.
• Experiment with soil mixtures (for example, sand mixed with clay).
• Try adding gravel or other stabilizers to see if they reduce shifting.

• Protect surfaces with a mat or tray to prevent scratching from sand grains.
• Handle containers carefully to avoid spills of soil or water.
• Wash hands after handling soil.
• Do not eat or put hands near the face during the experiment.

• How did each soil behave while being shaken? (Peat often compresses, sand may liquefy, topsoil may provide more stability.)
• Which soil caused the house to sink the most? Why?
• Which soil type provided the best stability for the house? (Likely topsoil, depending on water content.)
• What real-world implications does liquefaction have for buildings during earthquakes? (Foundations may shift or collapse.)
• How do engineers reduce liquefaction risk in construction? (By using deep foundations, soil compaction, or ground improvement techniques.)