What is the difference between magnitude and intensity?
Magnitude is a value related to the energy generated by an earthquake. It is a fixed number that does not vary regardless of which island you are located. For example, the duration magnitude of the Martinique Earthquake (2007/11/29) which was widely felt throughout the Eastern Caribbean was 7.3.
Intensity scales categorise the severity of an earthquake at a given location by describing the effects on people, structures and geological formations (e.g. whether or not buildings were damaged, whether items fell from shelves etc.) Each degree of intensity is described by a Roman numeral, (I, II, III etc.) the largest being XII, and the effects of the earthquake roughly double in severity for each one-division increase in intensity. The intensity of an earthquake varies depending on where you are in relation to the earthquake’s epicenter. For example, the intensity of the Martinique Earthquake (2007/11/29) was roughly V in Trinidad and VI and higher in Martinique.