EARTHQUAKES

Lowercase earthquake in a name:

            Loma Prieta earthquake.

In recent years seismologists have abandoned the familiar Richter scale for measuring earthquakes and now use the more precise moment-magnitude scale, which measures the total energy released by quakes:

            a magnitude 6 quake (no hyphen)

            recording 7.1

            2.5 to 3 magnitude tremor (do not use decimals with round numbers)

Magnitude is abbreviated M:

            an M 7.3 quake

Do not hyphenate P waves and S waves as nouns.