Norway recently gave some publicity to a decades old military practice. This involves storing and maintaining large quantities of American military equipment in Norway so that all the Americans have to do is fly the troops in and in less than a week you have a fully equipped combat troops ready for action. In Norway the stored gear for is sufficient for over 15,000 marines and is underground in seven caves. This publicity was apparently for sending a message to the Russians. While the U.S. has similar stored equipment worldwide Norway is unique in that the prepositioned gear is kept in caves. Most prepositioned gear elsewhere is on ships or in warehouses at military bases.
This prepositioning of military equipment goes back to the 1960s when the U.S. began pulling combat divisions out of Europe but still wanted to be able to bring these units back quickly if the Russians threatened an invasion. The solution was prepositioned equipment for several divisions of soldiers and marines. After the Cold War ended in 1991 the army and marines adjusted their prepositioned equipment deployment. The decade’s old prepositioned equipment program placed gear near potential hot spots. Throughout the Cold War, most of the prepositioned equipment was in Europe. Since the 1990s some was moved to the Persian Gulf and Korea. But one brigades worth was kept in Europe, and another was stored on ships off the Indian Ocean island of Diego Garcia. After the 2003 Iraq invasion there were three brigade sets in the Persian Gulf, one afloat off Guam, one in Korea and one still in Europe.
The U.S. Marine Corps gear in Norway was a special case. This stuff has been there since the early 1980s, in order to assist in the defense of Norway if the Russians invaded. Such an invasion has been moot since 1991, but the gear in Norway continued to be maintained, and even updated with new equipment. Congress pressured the marines to get the stuff out of the Norwegian caves and put it somewhere more else. The marines withstood this pressure and that proved to be a smart move because now the Russians are a threat once more, something the Norwegians long predicted would happen.
This stored equipment has actually been used for something other than training exercises. Prepositioned gear got a workout during the 2002-7 Iraqi operations and the troops were very pleased with the reliability and readiness of the prepositioned gear. The equipment is maintained by civilians, under military supervision and the Norwegian maintainers are seen as the most effective.
The other prepositioned marine equipment is abroad ships. The U.S. Navy Maritime Prepositioning program cost about $7 million per ship per year to maintain. The navy MSC (Military Sealift Command) maintains sixteen of these ships, to carry heavy equipment and supplies for the U.S. Marine Corps. These ships are organized into three squadrons with one stationed in the Atlantic, Pacific and Indian Oceans. Each group of ships carries the equipment for a marine brigade and enough supplies it going for 30 days. All you have to do is fly the marines in, land the equipment, and you have a marine brigade ready to fight. The process takes less than a week.
In each squadron, equipment is dispersed among the five ships so that the loss of one ship does not eliminate an entire category of equipment. Thus each ship in the squadron carries approximately 15 M1A1 tanks, 28 AAVs (amphibious assault vehicles, armored carriers for infantry), 153 Humvees, 100 MTVR (heavy trucks that can carry 15 tons of stuff on a road, half that cross country), two mechanized landing craft, eight 155mm towed howitzers, and 550 containers filled with spare parts, ammunition, medical supplies, food, and other material needed to keep a Marine brigade (17,300 Marines and Sailors) going for 30 days. The MPF squadrons performed well during the 2003 Iraq campaign, with their stored equipment being ready for action when unloaded.
Politics decides whether U.S. troops are used overseas, and politics can change. You can't quickly change your ability to move troops quickly. If you have to get a lot of firepower to a distant trouble spot, bombers don't always provide sufficient intimidation. Shiploads of tanks and troops deliver a more powerful message. In a world prone to random violence, ships that wait provide a quiet measure of security, as do caves in Norway.