The shear modulus is a measure of the rock's resistance to shearing, or sliding. It is defined as the ratio of the shear stress to the shear strain.
Earthquake fracture energy is important because it can be used to estimate the size of an earthquake and the amount of damage it can cause. Earthquakes with high fracture energies are more likely to cause damage than earthquakes with low fracture energies.
How an earthquake stops
An earthquake stops when the energy released by the rupture of the Earth's crust is dissipated. This can happen in a number of ways, including:
* Radiation of seismic waves: Seismic waves are vibrations that travel through the Earth's crust. They carry energy away from the earthquake source, and dissipate it as they travel.
* Friction: Friction between the two sides of the fault that slipped can slow down the rupture and eventually stop it.
* Plastic deformation: Plastic deformation is the permanent deformation of a material. It can occur when the rock on either side of the fault is squeezed or stretched beyond its elastic limit. Plastic deformation can absorb energy and slow down the rupture.
The relative importance of these different mechanisms in stopping an earthquake depends on the size of the earthquake, the type of rock that is involved, and the geometry of the fault.
