Seismic magnitude scales Seismic magnitude scales Seismic magnitude scales are used to describe the overall strength or "size" of an earthquake. These are distinguished from seismic intensity scales that categorize the intensity or severity of ground shaking (quaking) caused by an earthquake at a given location. Magnitudes are usually determined from measurements of an earthquake's seismic waves as recorded on a seismogram. Magnitude scales vary on the type and component of the seismic waves measured and the calculations used. Different magnitude scales are necessary because of differences in earthquakes, and in the purposes for which magnitudes are used. The Earth's crust is stressed
Natural monopoly professionals such as jewellers, physicians and lawyers, he said, The superiority of reward is not here the consequence of competition, but of its absence: not a compensation for disadvantages inherent in the employment, but an extra advantage; a kind of monopoly price, the effect not of a legal, but of what has been termed a natural monopoly... independently of... artificial monopolies [i.e. grants by government], there is a natural monopoly in favour of skilled labourers against the unskilled, which makes the difference of reward exceed, sometimes in a manifold proportion, what is sufficient merely to equalize their advantages. If unskilled