Seismic moment
The seismic moment is - as the seismic energy or magnitude - a measure of the strength of an earthquake.
It is calculated from
In which
- The shear modulus of the rock along the fracture surface (usually 30 gigapascals )
- The area of the fracture surface
- The average displacement along the fracture surface A is.
For historical earthquakes, the seismic moment from geological estimates of the fracture surface and the displacement can be calculated, estimates are for today's earthquake calculated from the seismograms within a short time.
The seismic moment is the basis of moment magnitude scale, the usual today in seismology measure of the strength of an earthquake.
- Earthquake
- Seismic