The most remarkable feature about the magnitude scale was that it worked at all and that it could be extended on a worldwide basis. It was originally envisaged as a rather rough-and-ready procedure by which we could grade earthquakes. We would have been happy if we could have assigned just three categories, large, medium, and small; the point is, we wanted to avoid personal judgments. It actually turned out to be quite a finely tuned scale.

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

Don't wait for extraordinary circumstance to do good; try to use ordinary situations.

Refining is inevitable in science when you have made measurements of a phenomenon for a long period of time.

Nothing is less predictable than the development of an active scientific field.

[In plotting earthquake measurements] the range between the largest and smallest magnitudes seemed unmanageably large. Dr. Beno Gutenberg then made the natural suggestion to plot the amplitudes logarithmically.

It is a common remark that men talk most who think least; just as frogs cease their quacking when a light is brought to the water-side.