What is earthquake intensity (Modified Mercalli)?
In contrast with magnitude, which represents the intrinsic size of an earthquake, intensity relates to information about public perception & damage. Since that varies with location, intensity is normally displayed on a map. The Modified Mercalli Scale has twelve levels, each with a description, generally displayed with Roman numerals to easily distinquish it from magnitude. MMI I means the earthquake was not felt; too small to feel at that location. MMI XII means total destruction (MMI XII is very rare & normally occurs right on top of a fault surface rupture or area of soil liquefaction). For the full list, see http://neic.usgs.gov/neis/general/mercalli.html. MMI takes into account the different types of building construction, so it represents the strength of the ground shaking at the location.
