The "snowballing opposition" to deploying the new MX intercontinental ballistic missile in the valleys of Nevada and Utah underscores the need for the Pentagon to reconsider putting more missiles at sea instead, according to Sen. Mark Hatfield (R-Ore.).

Hatfield has complained that the Air Force has opposed the idea of more missiles at sea without showing him its reasons. He said some or all of the current force of land-based Minuteman missiles could be put to sea in a small-submarine system called shallow underwater missile, or SUM. Hatfield is a leading proponent of SUM.

Two scientists championing the SUM alternative, Sindey Drell of Stanford University and Richard Garwin of IBM, have said the submarines also could carry the MX missile the Pentagon wants to deploy on land. Air Force plans call for placing the MX in a racetrack pattern of shelters to make it hard to hit and destroy.

At a recent House subcommittee hearing, William J. Perry, director of Pentagon research, said than any submarine cruising in the shallow waters of the continental shelves would be vulnerable, especially to what is known as the Van Dorn effect. This is the energy released from an underwater nuclear explosion, sending out waves that build into a tidal wave, endangering vessels in shallow water.

The Soviets, he said, could exploit the Van Dorn effect in a war by lobbying a nuclear bomb into the continental shelf, releasing so much energy that a giant tidal wave would turn over and destroy any submarines lurking there.

Saymour L. Zeiberg, a strategic specialist in the Pentagon's research office, said the Van Dorn effect is one reason a SUM cruising in relatively shallow water did not make sense. Building a SUM for deep water patrol, he continued, would not provide an improvement over the existing Trident missile submarine.

Hatfield, Drell and Garwin countered that they have not seen any data showing that SUM is not feasible. In a joint statement, Drell and Garwin said:

"Our proposal calls for deploying" SUMs "in coastal strips 200 miles wide in order to distribute the minisubs over a broad enough ocean area so that the force cannot be barraged at any depth.

"Vulnerability to the Van Dorn effect could exist in at most 20 percent of the originally proposed deployment area of 200-mile-wide bands off the continental U.S. coastlines.

"By moving the East Coast deployment further offshore by as much as 100 miles -- which would have no significant impact on our basing concept, including its command and control chain, its guidance procedures and its invulnerability to antisubmarine warfare -- the entire concern is totally removed."

Zeiberg is preparing a report for release soon to make the Pentagon's case against SUM as an alternative to a land-based MX.