Preferred term

Seismic moment

Description

Characterisation of the energy released by the earthquake as seismic waves. It is proportional to the fault surface and the mean slip. The seismic moment can be related to the moment magnitude.
The magnitude of the component couple of the double couple that is the point force system equivalent to a fault slip in an isotropic elastic body. It is equal to rigidity times the fault slip integrated over the fault plane. It can be estimated from the far- field seismic spectrum or waveform fitting at wavelengths much longer than the source size. It can also be estimated from the near-field seismic, geologic and geodetic data, and the consistency among various observations. This was first demonstrated for the Niigata, Japan, earthquake of 1964, supporting quantitatively the validity of the fault origin of an earthquake. Also called “scalar seismic moment” to distinguish it from moment tensor.