The University of South Carolina accepted an invitation to join the Southeastern Conference last night, becoming its 12th member.

"This decision culminated more than three months of growing expectation during which the university and the SEC became increasingly convinced that our membership in the SEC would be very good for both of us," South Carolina's interim president, Arthur K. Smith, said at a news conference at Williams-Brice Stadium in Columbia, S.C.

The SEC hopes to integrate all South Carolina sports except football into the league by the 1991-92 season. The school's participation in football probably will be postponed at least one year because of scheduling problems, officials said.

The move follows the addition of Arkansas to the SEC in July.

The Miami Herald, meanwhile, was reporting in today's editions that the Big East conference has voted to expand and will ask the University of Miami to join.

According to university and conference sources, Athletic Director Sam Jankovich will brief university officials about the proposal. The sources indicated, the Herald reported, that Jankovich will not recommend that Miami join; however, he does endorse the alignment.

Jankovich met for three hours yesterday with Big East Commissioner Mike Tranghese and athletic directors from Syracuse, Boston College and Pittsburgh, the three Big East schools that play Division I-A football, as does Miami.

The talks took place outside the structure of the first day of the league's two-day business meeting, Tranghese said.

The moves toward realignment was triggered last year by Penn State's acceptance of an invitation to join the Big Ten Conference.

Since an athletic directors' convention in June, Arkansas and South Carolina have joined the SEC, Florida State has been added to the Atlantic Coast Conference, and talks among various schools and conferences are happening on a daily basis.

South Carolina's move to the SEC marks a return to conference membership in both football and basketball that it has not had since the school quit the ACC in 1971, following a squabble with other conference members over academic standards. In 1983 South Carolina joined the Metro Conference, which does not compete in football.

Florida State also was a football independent that competed in the Metro Conference.

Tranghese and other officials of nonfootball leagues are fearful that the realignment and expansion into so-called super conferences will result in those leagues' negotiating with the networks for football television rights when the College Football Association contract with ABC -- which is being challenged by the Federal Trade Commission -- expires in 1996.

There is no entry fee to join the SEC, which only requires annual dues of $50.

South Carolina, which received $60,000 from the Metro last year, now will share in the SEC's revenue-sharing plan. Last year SEC teams received between $1.7 million to $3.0 million.