Theory 1

# EMSC 3002

## Module3.1 - Stress

- Louis Moresi (convenor)
  - Romain Beucher (lecturer)
  - **Chengxin Jiang** (lecturer)
  - Stephen Cox (curriculum advisor)

Australian National University

_**NB:** the course materials provided by the authors are open source under a creative commons licence. 
We acknowledge the contribution of the community in providing other materials and we endeavour to 
provide the correct attribution and citation. Please contact louis.moresi@anu.edu.au for updates and 
corrections._

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## Resources

1. **Fossen, H, 2011.** *Structural Geology.* Cambridge University Press, 2nd Edition. [E-learning modules](https://folk.uib.no/nglhe/module4/Chapt4module.html)
1. **van der Pluijm, B.A. and Marshak, S., 2003.** *Earth Strcture: an introduction to structural geology and tectonics.* W. W. Norton & Company, Ltd.
1. **Davis, G.H. and Reynolds, S.J., 1996.** *Structural Geology of Rocks and Regions.* 2nd Edition, John Wiley & Sons. 
1. **Park, R.G., 1995.** *Foundations of Structural Geology.* Blackie & Sons Ltd.

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## Intended learning outcomes

What you will learn about stress.

- The general concept of force and stress
- Express the stress state in 2D and 3D
- Computing traction vector along a plane using stress tensor
- Derivation and usage of the Mohr circle
- How we measure stress inside the Earth

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## HOW WE MEASURE STRESS
***Hydraulic fracturing*** is frequently applied to petroleum reservoirs to increase the near-well permeability and it means increasing the fluid pressure until the rock fractures. It relies on the theory that pore fluid pressure reduces the effective stress, which is the stress at grain contacts in porous rocks.

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