矩震级是记录地震强度的标度。1977年由美国加州理工学院的地震学家金森博雄教授制定。计算公式为:

其中为地震矩。

由公式可以看出，矩震级每增加一级需要倍的能量，也就是约31.6倍的能量。公式中使用的常数是为了使此标度与其他地震近震震级（如里氏地震规模）的数值相似。史上最强烈的地震为1960年智利大地震，规模为9.5。

矩震级的优点在于它不会像近震震级那样容易饱和。亦即，大于某震级的所有地震之数值都相同的情况不会发生。另外，此标度与震源的物理特性有较直接的联系。因此，矩震级已经取代近震震级成为世界地震学家估算大规模地震时最常用的标度。美国地质测量局对规模小于3.5级的地震不使用矩震级。

The moment magnitude scale (abbreviated as MMS; denoted as M_W or M) is used by seismologists to measure the size of earthquakes in terms of the energy released. The magnitude is based on the seismic moment of the earthquake, which is equal to the rigidity of the Earth multiplied by the average amount of slip on the fault and the size of the area that slipped. The scale was developed in the 1970s to succeed the 1930s-era Richter magnitude scale (M_L). Even though the formulae are different, the new scale retains a similar continuum of magnitude values to that defined by the older one. Starting in January 2002 the MMS is officially the scale used by the United States Geological Survey to calculate and report magnitudes for all modern large earthquakes.