stress and-types-of-stress 1
TRANSCRIPT
Bahria UniversityDepartment Of Earth & Environmental
SciencesStructural GeologyDecember 3, 2015
Presentation Topic:- Stress and its TypesPresenters:- Ahsan khan
Stress and Types of Stress
StressO Stress is conventionally defined as a
force acting on some area.
Fig 1
O Figure 1. Stress is defined as a force (F) acting on some area (A).
O Figure 1 illustrates a force, F, acting on area A. In the form of an equation this becomes
O where s is stress. Newton's first and second laws of motion provide key ingredients for an understanding of force, the principal parameter in Equation (1).
Types of StressO Compressional Stress
O Tensional Stress
O Shear Stress
Compressional StressO causes the rocks to push or squeeze
against one another.O can cause either horizontal or
vertical orientation,
Compressional StressO Compression causes reverse faults.
Tensional StressO Tension is the opposite of
compression,.
O tension forces the rocks to pull apart,
O A rock that has experienced such type of stress tends to be narrower and elongated than its original shape.
Tensional StressO Tensional stress produces normal
faults.
Shear StressO Forces from opposite direction, In
which forces run parallel to each other.
O The scale of shear stress can vary from few cm to hundreds of meters.
Shear StressO Shear stress produces strike-slip
fault.
Stress in Plate Tectonics
O Plate movement generates stress in the rocks at plate boundaries.
O At converging plate boundaries rocks are squeezed (compression),
O At diverging plate boundaries they are stretched (tension or extension),
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