- Emergency Action Message
An Emergency Action Message (EAM) is a preformatted message that directs nuclear-capable forces to execute specific
Major Attack Options(MAOs) or Limited Attack Options(LAOs) in a nuclear war. Individual countries or specific regions may be included or withheld in the EAM, as specified in the Single Integrated Operational Plan(SIOP).cite web |url=http://jitc.fhu.disa.mil/ot&e/eam.htm |title=JITC EAM OT&E SUPPORT |accessdate=2007-11-24 |format= |work= ]
In the United States, the EAM will be issued from the
National Military Command Center(NMCC) at the Pentagon or, if it has been destroyed by an enemy first strike, by the National Military Command Center - Site Rat Raven Rock or by the Boeing E-4B National Airborne Operations Center(NAOC).
The messages are sent in digital format to nuclear-capable major commands via the secure Automatic Digital Network (
AUTODIN). The messages are then relayed to aircraft that are on alert by the Strategic Command at Offutt Air Force Base in Omaha, Nebraska, via single-sideband radio transmitters of the High Frequency Global Communications System (formerly known as the Global High Frequency Service). The EAM is relayed to missile-firing nuclear submarines via special transmitters designed for communication with submarines. The transmitters include those designed to operate at Very Low Frequency(VLF). The submarines pick up the message via special antennas.
The contents of an EAM change daily, but follow a standard format. They consist of the twenty-six letters of the English alphabet and, out of a numerical set of zero through nine, only the digits 2 through 7, read by a human voice using the NATO phonetic alphabet. The first two characters generally do not change over a 14 day (+/-) period, but can change in less than 24 hours or remain static up to a period of many weeks. As of 01 October 2000 there are usually 28 characters, but often as few as 6 to as many as hundreds of characters, in an EAM. An EAM is usually sent during specific transmission windows twice an hour.
Regular monitoring by shortwave listeners, including Jeff Haverlah, who has specialized in the EAM, have determined the content of the EAM.
The EAM is divided into two parts, the Preamble, and the Content. The Preamble, usually an alphanumeric 6-character string, contains the authenticator. According to a video on YouTube,  the first two characters of the EAM indicate which authentication table the combat crew is to use to authenticate the message. This video is a video taken during a tour of the Titan Missile Base and Museum near Tucson, AZ. It is presumed that the additional 4 characters of the Preamble are the actual authentication code.
In the documentary "
Missile", trainees undergoing their final proficiency test receive a 26-character EAM, which they copy using grease pencils on a plastic card. They then compare their cards for a valid message, and then open a safe in which their orders are kept.
Procedures require that every EAM must be authenticated by the use of a code. Not only must the code be found to be valid, but it must also be up to date. Once an EAM has been received, two weapons officers must agree that it is authentic. If they are on land, they will have laminated red cards -- either around their necks, or in their wallets -- against which to check the EAM code. If they agree that it matches, then they will be expected to enter
Permissive Action Link(PAL) codes into the nuclear device. If the PAL codes are not entered simultaneously, the weapon will not be armed.
Nuclear-capable forces will then be expected to carry out an EAM without fail. Thereafter, manned bombers may be recalled, but missiles fired from land-based silos or from submarines cannot be recalled.
* [http://www.dod.mil/pubs/foi/reading_room/320.pdf FOIA Release of JCS-EAP Volume V - Nuclear Control Orders (U)]
* [http://www.youtube.com/watch?v=CkeTAlQ1yi4&feature=related Emergency Action Message] Video on
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