What is the seismic moment of an earthquake and what is it used for?

Question

Isaac Abel · Accepted Answer

Seismic moment is measure of the size of an earthquake and it is used in order to calculate moment magnitude.

Seismic moment is an important value for earthquake magnitude determination. Seismic moment , #M_0#, is related with the rigidity of the eartquake source region, #mu#, area of the fault plane, #A# and average displacement, #D#. Equation of #M_0# can be seen as below, #M_0 = mu A D# By using #M_0# moment magnitude, #M_w# can be calculated, #M_w = 2/3 log(M_0) - 10.7#. Determining #M_w# is important since, #M_w# cannot saturate unlike other magnitude scale. This property of #M_w# comes from the feature of #M_0#. Other magnitude types are depended with certain part of seismic records. Seismic records, however, can satured if the magnitude of the earthquake is bigger than a certain magnitude. Because of that #M_0# has a vital role on modern seismology. The strain energy released during earthquakes can also be used to interpret the seismic moment.

Benjamin Awad · Answer

undefined The seismic moment of an earthquake is a measure of the total energy released by the earthquake. It is calculated using the earthquake's magnitude, the area of the fault that ruptured during the earthquake, and the amount of slip along the fault. The seismic moment provides a more comprehensive measure of an earthquake's size and energy release compared to magnitude alone. It is used by seismologists to better understand the characteristics of earthquakes, assess earthquake hazards, and improve seismic risk assessments and building codes.