Emergency Action Message
Encyclopedia
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).
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 Alternate National Military Command Center - Site R
at 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 modulation
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.
Nuclear-capable forces will then be expected to carry out an EAM without fail. Manned bombers may be recalled, but missiles fired from land-based silos or from submarines cannot be recalled.
Nuclear warfare
Nuclear warfare, or atomic warfare, is a military conflict or political strategy in which nuclear weaponry is detonated on an opponent. Compared to conventional warfare, nuclear warfare can be vastly more destructive in range and extent of damage...
. Individual countries or specific regions may be included or withheld in the EAM, as specified in the Single Integrated Operational Plan
Single Integrated Operational Plan
The Single Integrated Operational Plan was the United States' general plan for nuclear war from 1961 to 2003. The SIOP gave the President of the United States a range of targeting options, and described launch procedures and target sets against which nuclear weapons would be launched...
(SIOP).
In the United States, the EAM will be issued from the National Military Command Center
National Military Command Center
Located in the Pentagon, the National Military Command Center houses the logistical and communications center for the National Command Authority of the United States of America. The facility, which is composed of several war rooms, is the principal command and control center of the Department of...
(NMCC) at the Pentagon
The Pentagon
The Pentagon is the headquarters of the United States Department of Defense, located in Arlington County, Virginia. As a symbol of the U.S. military, "the Pentagon" is often used metonymically to refer to the Department of Defense rather than the building itself.Designed by the American architect...
or, if it has been destroyed by an enemy first strike, by the Alternate National Military Command Center - Site R
Site R
The Raven Rock Mountain Complex is a United States government facility on Raven Rock, a mountain in the U.S. state of Pennsylvania. It is located in Liberty Township, Adams County, about east of Waynesboro, Pennsylvania, and north-northeast of Camp David, Maryland. It is also called the Raven...
at 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
Offutt Air Force Base
Offutt Air Force Base is a U.S. Air Force installation near Omaha, and lies adjacent to Bellevue in Sarpy County, Nebraska. It is the headquarters of the U.S...
in Omaha, Nebraska
Omaha, Nebraska
Omaha is the largest city in the state of Nebraska, United States, and is the county seat of Douglas County. It is located in the Midwestern United States on the Missouri River, about 20 miles north of the mouth of the Platte River...
, via single-sideband modulation
Single-sideband modulation
Single-sideband modulation or Single-sideband suppressed-carrier is a refinement of amplitude modulation that more efficiently uses electrical power and bandwidth....
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
Communication with submarines
Communication with submarines is difficult because radio waves do not travel well through thick electrical conductors like salt water.The obvious solution is to surface and raise an antenna above the water, then use ordinary radio transmissions. Early submarines had to frequently surface anyway for...
. The transmitters include those designed to operate at Very Low Frequency
Very low frequency
225px|thumb|right|A VLF receiving antenna at [[Palmer Station]], Antarctica, operated by Stanford UniversityVery low frequency or VLF refers to radio frequencies in the range of 3 kHz to 30 kHz. Since there is not much bandwidth in this band of the radio spectrum, only the very simplest signals...
(VLF). The submarines pick up the message via special antennas.
Nuclear-capable forces will then be expected to carry out an EAM without fail. Manned bombers may be recalled, but missiles fired from land-based silos or from submarines cannot be recalled.