If one introduces the concept of energy of an earthquake then that is a theoretically derived quantity.

If the assumptions used in calculating energy are changed, then this seriously affects the final result, even though the same body of data might be used.

In every area of the world where there is earthquake risk, there are still many buildings of this type; it is very frustrating to try to get rid of them.

As seismologists gained more experience from earthquake records, it became obvious that the problem could not be reduced to a single peak acceleration. In fact, a full frequency of vibrations occurs.

By moving them vertically, a representative mean curve could be formed, and individual events were then characterized by individual logarithmic differences from the standard curve.

For example, some stars put out large amounts of energy in the infrared part of the spectrum, so that this can produce a different relative magnitude rating than using light energy from the middle of the spectrum.