The move was already being felt on Friday afternoon. Instead of scenes of fraternity brothers drinking and playing games on their lawns and porches, the only visible activity was found in the yard outside Theta Delta Chi, where students were selling doughnuts and apple cider to raise money for the Breast Cancer Research Fund.

The suspension was a major topic of conversation at the food court in the basement of the student union, where three different groups of young men were overheard complaining about the cancellation of parties this weekend, though they declined to speak with a reporter.

Henry Flynn, a 19-year-old sophomore, said he rushed a few fraternities last winter before deciding against pledging after his roommate was taken to the hospital with alcohol poisoning after a Greek event. Mr. Flynn recalled one activity where potential pledges moved from room to room participating in different drinking games, and another in which they were tested on how they answered women’s invasive questions about their sexual histories.

While fraternities often speak publicly about their charitable work, Mr. Flynn heard little about that during rush. “The focus was how you fit into this community based on how much you party,” he said. “That was the vibe I got.”

Another sophomore, Tiffany Liu, recalled a friend being hit on by a fraternity pledge who said that part of his hazing required him to have intercourse with a woman. Fraternities were “the main source of propagating hookup culture,” Ms. Liu said. “That’s what their parties are about.”

Mr. Fitzgerald, the spokesman for the university, which has 29,000 undergraduates, said that school authorities and the local police were looking into all of the misconduct complaints.

Mr. Fitzgerald said sororities at Michigan do not normally host parties at their houses, so they would not be affected by the suspension. And the decree affects only fraternities that fall under the purview of the Interfraternity Council, leaving the four predominantly African-American fraternities that are part of the National Pan-Hellenic Council free to continue hosting social events.