Moment magnitude scale The scale was unable to characterize these "great earthquakes" accurately. The difficulties with use of in characterizing the quake resulted from the size of these earthquakes. Great quakes produced 20 s waves such that was comparable to normal quakes, but also produced very long period waves (more than 200 s) which carried large amounts of energy. As a result, use of the modified Richter scale methodology to estimate earthquake energy was deficient at high energies. The concept of seismic moment was introduced in 1966 by Keiiti Aki, a professor of geophysics at the Massachusetts Institute of Technology. He employed elastic
Orders of magnitude (power) Orders of magnitude (power) This page lists examples of the power in watts produced by various sources of energy. They are grouped by orders of magnitude. The productive capacity of electrical generators operated by utility companies is often measured in MW. Few things can sustain the transfer or consumption of energy on this scale; some of these events or entities include: lightning strikes, naval craft (such as aircraft carriers and submarines), engineering hardware, and some scientific research equipment (such as supercolliders and large lasers). For reference, about 10,000 100-watt lightbulbs or 5,000 computer systems would be needed to draw 1