Complements - Sequence 2: Earthquakes

The following translation is graciously provided by ISTIC.

Herein are listed the documentary sheets to copy and distribute during the various sessions of Sequence 2, as well as video clips. The latter (documentaries or recorded experiments) can be either broadcast in class with a projector, or used by the teacher alone to facilitate the preparation of the sessions.

Sommaire

 


Session 2-1

Sheet 17

 

Sheet 18

 

Video (42 seconds)

These japanese buildings resist to the March 2011 earthquake: they sway but don't crumble down.

 

Session 2-2

Sheet 19

 

Sheet 20

 

Sheet 21

 

Sheet 22

 

Session 2-3

Video (13 seconds)

Recorded experiment (first at regular speed, then in slow motion) showing how small items (here dyed pasta) are moved by a jolt. Note that items closest to the centre of the apparatus (near the epicentre) are moved the most, both vertically and horizontally.

 

Session 2-4

Sheet 23

 

Session 2-5

Experiment showing that an earthquake can be produced by the sudden breaking of a tectonic plate (falt).
A wooden plank is fixed on a table with a clamp; it is deformed until it breaks. At that specific time, a vibration propagates into the plank. This vibration is visualised through the creation of waves visible in the aquarium setup on top of the plank.

 

Experiment showing that an earthquake can be produced by the sudden movement of a tectonic plate.
Here, we pulling the rubber band, constraints accumulate within the material, that are suddenly realeased in a jolt, because the friction is intense on this rugged ground. Again, the vibration can be seen through the waves in the aquarium.
A similar experiment on a smooth ground (wooden table, tiled floor) will not produce such vibrations, as the movement is achieved smoothly without jolts.

 

Another experiment showing that an earthquake can be produced by the sudden movement of a tectonic plate.
On the left, the plank movement is fluid and smooth, as it swipes easily on the table.
On the right, strong constraints must accumulate to move the plank (that was stuck with tape to the table). The movement occurs abruptly, initiating an earthquake.

 

 

Session 2-6

Sheet 24

 

Example of a seismograph built with magnets.
The magnetic pendulums are placed far enough not to be attracted to each other initially.
When a vibration occurs, the magnets oscillate until the attract each other again and stick together.

 

Session 2-7

Sheet 25

 

Session 2-8

Sheet 26

 

Tableau Excel

This chart was produced by the Ministry of Sustainable Development, listing the seismic zoning of the 36 721 French counties, i.e. the strength of the seismic risk: very weak, feeble, medium, sensible, extreme.

 

 

 

Session 2-9

Sheet 27

 

Session 2-10

Video (7 seconds)

Experiment showing that the height of a building is not a pertinent parameter to assess its resistance to earthquakes. Low-frequency vibrations will impact the highest buildings, while high-frequency ones will make the lowest buildings vibrate. As both frequencies are in general present within a seismic wave, there is no best height to choose for a building.

 

 

Session 2-11

Sheet 28

 

Sheet 29

 

Video (42 seconds)

Experiment of a shock absorber for seismic buildings. The building without absorbers collapses, while the other resists.

 

Simulation of a set of buildings built on wheels.
When the ground vibrates, such a system dampens the vibration and limitates the buildings collapse.
Note: using bottles instead of wheels (or even better: spheres) is an additional constraint. The vibration will only be dampened if its propagation is orthoghonal to the bottles. Yet such an apparatus can be used to determine the direction of a seismic wave.

 

 

Evaluation

Sheet 30

 

Sheet 31

 

Sheet 32

 

Sheet 33

Project partners

La main à la pâte Foundation ESA