8. Mike-Mike Reports¶
8.1. What’s a Mike-Mike?¶
We report damage using the Modified-Mercalli Scale. We refer to this using the MM abbreviation, which is voiced on the radio as “Mike-Mike” (the ISO phonetic pronounciation of the letter M is “Mike”).
The purpose of having a well defined scale is so that we can meaninfully collect multiple reports together and get a common picture of the town’s status.
We use the same system used by Santa Clara County Ares Races, so we can report results up the chain. (All jurisdictions in the county use the same system.
The official USGS Modified Mercalli scale (alternate reference) has 12 levels. Our county has truncated the table to 8 levels, with anything past Severe (MM-8) just counted as the same as Severe.
The goal of the scale is to report observable effects in a more consistent way. The lower numbers of the intensity scale generally deal with the manner in which the earthquake is felt by people. The higher numbers of the scale are based on observed structural damage
Here’s the scale and guidelines for what each level corresponds to:
| Mike-Mike Value | Shaking | Description / Damage |
|---|---|---|
| Mike-Mike 1 | Not Felt | Not felt except by a very few under especially favorable conditions. |
| Mike-Mike 2 | Weak | Felt only by a few persons at rest,especially on upper floors of buildings. |
| Mike-Mike 3 | Weak | Felt quite noticeably by persons indoors, especially on upper floors of buildings. Many people do not recognize it as an earthquake. Standing motor cars may rock slightly. Vibrations similar to the passing of a truck. Duration estimated. |
| Mike-Mike 4 | Light | Felt indoors by many, outdoors by few during the day. At night, some awakened. Dishes, windows, doors disturbed; walls made cracking sound. Sensation like heavy truck striking building. Standing motor cars rocked noticeably. |
| Mike-Mike 5 | Moderate | Felt by nearly everyone; many awakened. Some dishes, windows broken. Unstable objects overturned. Pendulum clocks may stop. |
| Mike-Mike 6 | Strong | Felt by all, many frightened. Some heavy furniture moved; a few instances of fallen plaster. Damage slight. |
| Mike-Mike 7 | Very Strong | Damage negligible in buildings of good design and construction; slight to moderate in well-built ordinary structures; considerable damage in poorly built or badly designed structures; some chimneys broken. |
| Mike-Mike 8 | Severe | Damage slight in specially designed structures; considerable damage in ordinary substantial buildings with partial collapse. Damage great in poorly built structures. Fall of chimneys, factory stacks, columns, monuments, walls. Heavy furniture overturned. |
When reporting Mike-Mike reports over the radio use this format:
<your call sign> <your zone> “Mike Mike” <mike-mike number> <your call sign>
For example:
Whisky 6 Xray Romeo Lima 4 Zone 33 Mike-Mike 3 W6XRL4