How can I model earthquake slip-stick behavior in the classroom?
Describes parts needed to build the Earthquake Machine.
The simplicity of the Earthquake Machine allows students to visualize the inputs and outputs of a fault system and explore stick-slip fault behavior. The model’s wooden block, rubber band, measuring tape and sandpaper base all represent an active fault section. Your pull on the measuring tape and rubber band attached to the block is analogous to slow, continuous plate motions. For example, this might represent the downward pull of a subducting slab of lithospheric plate, which is continuously adding tension to the system. The rubber band represents the elastic properties of the surrounding rocks, storing potential energy as they are deformed (yes, rocks actually bend elastically!). The sandpaper represents the contact between the sides of the fault. When the frictional forces between the block and sandpaper are overcome, the block lurches forward, representing ground motion during an earthquake. The description of this entire process (that is, the slow accumulation of strain energy in elastic material, followed by the released in a sudden slip event) is known as elastic rebound theory.
Shopping list: Wood block, sanding belts, rubber bands, eye bolt and tools
- What is elastic rebound?
- What does pulling a block with a rubber band have anything to do with earthquakes?
- What do the block, sandpaper, and rubber band represent in this analogy?
- What type of energy does a rubber band have?
- How does the energy change during an earthquake? The potential energy in the rubber band is transformed into kinetic energy when the block moves
- Does this show that earthquakes are predictable?