A sudden eruption of violence between the U.S. and Iran in the Persian Gulf is unfortunate, but it is no reason to believe that full-scale war has broken out. In many ways, it amounts to a replay of earlier events, although the intensity and scale is greater this time.

The fighting was touched off by the damage done to a U.S. frigate in international waters last week by an Iranian mine. President Reagan had warned Iran against laying mines in the gulf and evidence seems clear that new mines had been sown. Last September, the U.S. destroyed an Iranian ship caught laying mines in the gulf.In what was described by the president this week as a "measured response," the U.S. Navy destroyed two Iranian oil drilling platforms used as bases for speedboats to attack shipping in the gulf. The bombardment came after giving the occupants a brief warning to abandon the platforms.

That was exactly the same thing done last October after an Iranian missile attack against one of the reflagged Kuwaiti tankers. Two oil platforms were destroyed on that occasion as well.

The only real difference has been the Iranian response. Last October, most of the Iranian reaction was in the form of angry words. This time, Iran's navy, such as it is, came out fighting.

A speedboat tried to defend the oil platforms and was sunk. Later, two Iranian frigates steamed into the gulf and fired at U.S. aircraft. Bombs and missiles were fired at both frigates in return and both were left damaged and burning. Other Iranian gunboats went on a rampage, attacked neighboring Arab oil facilities, and commercial shipping in the southern gulf. One of these gunboats was sunk and two others damaged by U.S. warships.

For the first time, Iran fired Silkworm missiles at a group of U.S. warships, but all missed. A two-man U.S. helicopter was reported missing in the area of fighting.

It should be pointed out that the calm prior to this week's confrontation was deceptive. The tanker war between Iran and Iraq has never really abated since it began nearly four years ago, despite the presence of the U.S. Navy and warships from other nations starting in summer of 1987. Since 1981, some 11 million tons of shipping has been lost in the gulf. Compare that to 24 million tons of merchant shipping sunk in all of World War II.

The direct clash between the U.S. and Iran can hardly be expected to continue. It would be foolhardy on the part of the Iranians because they are clearly outgunned and overmatched. In addition, Iran is highly vulnerable because its vital oil terminals are right there on the coast, within range of U.S. planes and ships.

The U.S. is pledged to a principle in the gulf, namely the unhindered passage of its ships in international waters. Other nations have followed the U.S. lead and have sent warships to uphold the same principle for their own shipping.

Everybody, including Iran, would be better off if it would conclude its stupid eight-year war with Iraq. Neither is capable of winning, so why keep fighting? As long as the war lasts, more incidents are bound to happen. And each time, Iran is going to get punished in return. Peace is the only thing that makes sense.