What are Conservative plate margins?
Conservative plate margins are quite different in comparison to the other tectonic boundaries. The main reason for this is that no volcanic activity occurs at the margin, only earthquakes. This is because a conservative plate margin, sometimes known as a transform fault, is where two plates shear past each other without direct collision. At the margin plates either move in opposite directions past each other or move in the same direction but at different rates. A useful example of a conservative plate margin is the San Andreas Fault, a margin consisting of the Pacific Plate and North American Plates, shown in the diagram on the left.
The difference in movement of the plates allows for energy to build up from the friction between them. Friction between the plates restricts their movement, thus causing this build up of energy. Once the shear force of the plates kinetic energy is greater than the friction restricting there movement, energy is released in the form of Seismic Waves, which create an earthquake, and actual kinetic movement. To model this, think of rubbing two jagged rocks alongside each other to the point that they lock. Continue to apply pressure to the point that they, suddenly, move away from each other.
Why no volcanic activity?
The key to this answer lies within the movement of the plates. At a conservative plate margin plates will never move towards each other or away from each other, if they did it would be classed as a destructive or constructive plate margin. With plates only moving side by side nothing is being destroyed or weakened within the lithosphere to an extent in order to penetrate to the asthenosphere, where the molten magma lies.
The difference in movement of the plates allows for energy to build up from the friction between them. Friction between the plates restricts their movement, thus causing this build up of energy. Once the shear force of the plates kinetic energy is greater than the friction restricting there movement, energy is released in the form of Seismic Waves, which create an earthquake, and actual kinetic movement. To model this, think of rubbing two jagged rocks alongside each other to the point that they lock. Continue to apply pressure to the point that they, suddenly, move away from each other.
Why no volcanic activity?
The key to this answer lies within the movement of the plates. At a conservative plate margin plates will never move towards each other or away from each other, if they did it would be classed as a destructive or constructive plate margin. With plates only moving side by side nothing is being destroyed or weakened within the lithosphere to an extent in order to penetrate to the asthenosphere, where the molten magma lies.