The Modified Mercalli Scale is used as a way to cross reference an earthquakes Richter Scale reading with the perceived impact as reported by the people in the area of the earthquake. Like the Richter scale of 1 thru 10, the Modified Mercalli Scale also has 10 steps.

We use the phonetic “M” or “Mike” to reference the corresponding response. “Modified Mercalli” thus becomes “Mike Mike” for clarity and brevity. For example, when asked for “Mike Mike reports” you may respond with “Mike Mike 4” using the scale below.

Quickly collecting Mike Mike reports over the area hit by a large quake can inform as to where the most severe impact is in a particular area so that resources may be allocated accordingly and proportionately.

You can find more information and even download a printable wallet size card from the Santa Clara County ARES/RACES web site, here.