The geographic and historical distribution of earthquakes Seismic moment A measure of the size of an earthquake based on the area of fault rupture, the average amount of slip, and the shear modulus of the rocks offset by faulting Seismic moment can also be calculated from the amplitude spectra of seismic waves
The worldwide or local distribution of earthquakes in space and time; a general term for the number of earthquakes in a unit of time, or for a relative earthquake activity