The weapons pictured on these pages are some of those covered by the much debated SALT II treaty. There are three basic types of strategic nuclear weapons in the American and Soviet arsensals covered by the treaty - land-based intercontinental ballistic missiles (ICBMs), submarine-launched ballistic missiles (SLBMs), and heavy bombers several (mostly on the American side) soon to be loaded with long-range cruise missiles.

Some of the bigger weapons, the multi-megaton Soviet SS-9s, for example, are being phased out, replaced by multiple-warhead missiles, each smaller and more accurate. Nuclear war, military experts are now saying, can be fought more efficiently that way. Their idea is that instead of indiscriminately blowing up entire cities, war planners can hit their targets more selectively.

Still, these smaller weapons - most of them releasing the emergy of several hundred thousand tons of dynamite - will do enormous damage. It doesn't take many thermonuclear weapons to convulse a modern industrial society.

For example, only 10 Soviet SS-18 ICBMs could wipe out two-thirds of America's oil-refining capacity. Seven American Poseidon SLBMs and three Minuteman III ICBMs could, together, obliterate three-quarters of the Soviet Union's refineries.

Such an attack would use only about one percent of either side's nuclear arsenal. As well as disrupting a civilization highly dependent on fossil fuels, the attack would kill one or two million Soviets and five million Americans.

However, nuclear war would probably not begin with a bolt-from-the-blue strike on some petroleum refineries. The favorite scenario tossed around in the defense community these days goes something like this: In a moment of high political tension sometime in the 1980s, the Soviets launch about one-third of their ICBMs; more than 2,000 nuclear warheads plunge toward the United States at 15 times the speed of sound; with astonishing accuracy they destroy 90 percent of our ICBMs, those bombers left on the ground and those submarines still in port.

Many strategists discuss such an attack in abstract terms, surgical in their precision. The consequences, however, would hardly be so clean;.

When each nuclear weapon explodes, its blast sucks tons of dust and debris into a mushroom cloud 20 miles in diameter, 13 miles high. The particles forming the cloud "rain" back to earth, spreading lethal radioactive fallout for hundreds of miles downwind. Fallout from nuclear warheads striking missile fields near Kansas City could hospitalize half the residents of Washington, D.C., even if they stayed indoors.

In the first 30 days after a Soviet first strike intended only to destroy U.S. nuclear weapons, two to 20 million Americans would die. (Four to 28 million Soviets would die if we struck first.)

To discourage an attack of this kind, the United States is developing the MX missile, which would have a first-strike capability of its own. Moreover, it would be "hidden." The scheme is to install roughly 200 of these powerful missiles in trenches containing thousands of cement shelters. The missiles would be shifted secretly from shelter to shelter, preventing the USSR from knowing which shelter to aim at. The assumption is that there would not be enough Soviet warheads to destroy all the shelters and there would, thus, be no incentive to launch a first strike doomed to failure. The plan could be thwarted, however, if the Soviets built more warheads.

After the initial exchange, escalation would be almost inevitable. The superpowers have their missiles aimed and their bombardiers trained to destroy military and industrial facilities, not to kill people as such. Nevertheless, in an all-out nuclear war, 64 to 100 million Soviets and at least 100 million - as many as 130 million - Americans will probably die, according to a recent study by the Congressional Office of Technology Assessment.

Not much would remain for the survivors. Eighty percent of Soviet and American industry would be destroyed. The incidence of cancer, starvation and genetic mutation would skyrocket, worldwide, for years to come. The most elaborate civil defense system could provide little protection.

There are those who minimize the devastation. They point to Hiroshima, where the trains were running 48 hours after the A-bomb dropped. They ignore that the Hiroshima bomb released less than half the destructive energy carried by the smallest nuclear weapon in either side's strategic arsenal today. They ignore that nuclear bombs destroyed only two cities in Japan and that others came to their aid. The victims of a future nuclear war, in which all the major metropolitan centers may lie shattered, will have no such luck.

The debate over SALT II has publicized ICBM vulnerability, hard-target kill calculations and other esoterica of the nuclear hardware profession. Knowledge of the analytic issues is necessary for an understanding of strategy, the requirements of deterence, the full merits of nuclear armscontrol agreements and how roughly $15 billion of the U.S. budget is spent each year.

Obsessions with these issues, however, encourages a depersonalized discourse. It detracts attention from, and distorts, the fundamental facts about nuclear war - more than 100 million civilians will die hideously, the foundations of Soviet and American society will crumble and virtually no nation will remain untouched.

What the SALT debaters must decide is how best to ward off that calamity. CAPTION: Cover-photo, Minuteman III, Bill Snead; Pictures 1, 2, The panel above is part of the launch system for the U.S. Minuteman III (right), which has three 170-kiloton warheads that can land within 600 feet of three different targets. Even if only 10 percent of the 550 Minuteman IIIs are operational after a Soviet first strike, their warheads could be rapidly retargeted to destroy half the Soviet capacity to produce primary metals, chemicals, petroleum, synthetic rubber, electric power and equipment for construction, railroads and agriculture. During the next two years, three 335-kiloton Mk-12A warheads will be installed on 300 Minuteman III'S. By Bill Snead; Picture 2, Twelve cruise missles can be carried by a single B-52 bomber (left), along with four 1-megaton gravity bombs and eight 200-kiloton short-range attack missiles, the latter designed to destroy Soviet air-defense sites. Without bombs and other missiles, 20 cruise missiles could be carried by a single B-52. Boeing Aerospace Co.; Picture 3, The U.S. Tomahawk air-launched cruise missile (below) packs 200 kilotons of explosive power, is so small that Soviet radar can not track it in flight, and has a computer guidance system that can put the weapon down within 100 feet of a target after being fired from an airplane more than 1,500 miles away. General Dynamics; Pictures 4, 5, 6, Each of America's 31 Poseidon submarines (above), holds 16 Poseidon missiles, each with 10 warheads having the explosive power of 40,000 tons of dynamite (40 kilotons), a total of 4,960 warheads. Six Poseidon subs can destroy the 200 largest Soviet cities. During the next two years the missiles in 12 Poseidon subs are scheduled to be replaced with Trident I missiles (inset above), each with eight, longer-range, 100-kiloton warheads. Next year the first of 13 Trident subs (left) will put to sea. Each will carry 24 Trident I missiles, enough power to obliterate the 18 largest Soviet cities - more than 28 million people. In the late 1980s, Trident I missiles may be replaced by Trident II missiles with fourteen 150-kiloton warheads. U.S. Navy Photos; Picture 7, The 115-foot SS-9, with one 15-megaton warhead, can crush most buildings within 380 square miles (The District is 69 square miles). The Soviets have only 50 SS-9s, having replaced about 250 others with the SS-18. Some SS-18s have a single 20-megaton warhead, but most have eight 1-megaton or ten 600-kiloton warheads. Sovfoto; Picture 8, The United States has 1,054 land-based intercontinental ballistic missiles (ICBMs), and the Soviets have 1,400. Protected inside hardened concrete underground silos, they are becoming increasingly vulnerable as both sides upgrade warhead accuracy. The US has only 23 percent of its 9,200 strategic warheads on IBCMs, having spread out its nuclear force rather evenly among land-based missiles, submarines and bombers. The Soviets have concentrated about 75 percent of their 5,100 warheads on ICBMs. Soviet missiles are larger and more powerful, but U.S. missiles are more accurate, reliable and efficient. For example, the proposed MX would have only half the payload of the Soviet SS-18, but the same number of warheads (10) and a better chance of destroying the most blast-resistant of targets. U.S. Air Force; Picture 9, The U.S. Titan missile has a single 9-megaton warhead that can crumble buildings within 254 square miles, an area the size of Leningrad. Effects of the warhead's fireball would extend over 1,400 square miles, probably killing most people within that area. America has only 54 of these rockets because the military decided in favor of smaller, more accurate weapons in the 1960s. Martin Marietta Aerospace; Picture 10, The Soviet SS-11 is somewhat bigger than, but similar to, the U.S. Minuteman II. Both have a 1-megaton warhead, enough to destroy Washington. The Soviets have about 680 SS-11s, and 360 others have been replaced with SS-17s and SS-19s. Most SS-17s have four 750-kiloton warheads; most SS19-s have six 550-kiloton warheads. Sovfoto; Pictures 11, 12, 13, 14, In a test, a two-ton Missile Experimental punches its way out of an earth-and-concrete-covered shelter, ready to be launched. In the proposed MX system, the missiles will probably be deployed in 20-mile trenches to evade Soviet attempts to destroy them. Each missile would be shuttled randomly among 44 horizontal shelters in each trench, ready to be hoisted by huge levers upward through the shelter covering. The MX, with just less than an 8,000-pound payload, can deliver 10 independently target able warheads of 335 kilotons, each landing within a football field of its target, virtually assuring destruction of even the most protected enemy missile sites. The United States plans to build 200 MX missiles at a cost of about $40 billion. The strategy behind the trenches and multiple shelters is to evade a first strike by forcing the Soviets to target warheads for each of the horizontal shelters. The Soviets, however, could deploy a similar system and we might have no way of knowing how many missiles would be in their trenches. Another problem is that the Soviets could put enough warheads on their ICBMs to match the number of shelters we build. SALT II prohibits the Soviets from placing more than 10 warheads on each ICBM, but the treaty will expire in 1985, and the MX would not be deployed until 1986. U.S. Air Force Photos; Map, WASHINGTON'S 1-MEGATON BLAST SCENARIO: Circle 1 shows the area within which reinforced concrete structures would collapse from a blast. Out to circle 2, lighter concrete buildings would crumble. Enough pressure would be felt as far out as circle 3 to destroy all brick and wood-framed buildings and to severely damage those made of reinforced steel. Fires directly caused by the heat of the weapon's fireball would be fueled out to circle 4. Circle 5 designates the area within which people exposed to the fireball would receive possibly fatal third-degree burns - nearly eight miles from the explosion. Within the final circle, property would be destroyed and people in the open would have their eardrums damaged and receive second-degree burns. One-megaton weapons in the U.S. arsenal include 450 Minuteman II ICBMS and about 1,750 gravity bombs carried by B-52 bombers. Those in the Soviet force include 680 SS-11 and 60 SS-13 ICBMs. The largest weapon held by either side is 20 megatons - the single-warhead version of the Soviet SS-18 ICBM, probably fewer than 50 in number. The blast area of a 20-megaton bomb is 4 1/2 times that of a one-megaton weapon, and the area within which people would receive third-degree burns is three times as large. By Richard Furno