Stick-Slip as a Mechanism for Earthquakes and Friction.pptx

Earth sciences depiction of Strike-slip methods

1. Stick-Slip as a Mechanism for Earthquakes and Friction of Rocks ( Byerlee , 1966 & 1978) Hailey Huffman and Cameron Wiksell

2. Vocabulary

3. Reid’s Theory vs Laboratory Execution Earthquakes are the result of sudden shearing motion across the fault.

4. What is stick-slip? The jerky motion of the rock bodies sliding past each other After continuous stress build up, rock body snaps to release the stress. Stress can be reapplied. These snaps can cause earthquakes in shallow depths The jerky motion can be interpreted as the tangential force of the spring (points A-B) shown in Figure 1. Figure 2 is the linear function of the force and displacement of the spring in figure 1.

5. What is stick-slip? The tangential shear force μ= τ/σₙ μ = coefficient of friction Τ = normal stress σₙ = sheer stress In high pressures Linear law: Τ = A + B σₙ μ = B + A/ σₙ B and A are constants

6. Friction of Rocks under Low Pressures Pressure conditions up to 50 bars (5 MPa) Straight line represents the friction at intermediate pressure ( Τ =0.85 σₙ ) coefficient of friction between 0.3-10 friction variation is due to how rough the rock surfaces are

7. Friction of Rocks under Intermediate Pressures Pressure conditions up to 1,000 Bars (100 MPa)

8. Friction of Rocks under High Pressures Pressure conditions up to 17,000 Bars (1,700 MPa)

9. Why is this important? Civil Engineers slope stability in structures like dams and road cuts Geophysicists earthquakes Mining Engineers design solutions of mines that are deeper than 3 km

10. Further Discussion