Nationwide Box Office Plunges : Receipts: Movie industry sources say that grosses were down about 37%, partly due to civil unrest in the L.A. area.

Box-office grosses plunged across the country this weekend, as moviegoers in major urban areas stayed home after rioting wracked Los Angeles and other cities in the aftermath of the Rodney G. King verdict.

Film industry sources estimated that grosses across the nation were down by about 37%. Among the top 10 movies, ticket sales fell from about $33.9 million a weekend earlier to an estimated $21.3 million for the most recent Friday-Saturday-Sunday period.

The nation’s No. 1 film continued to be the violent, sexually charged “Basic Instinct,” starring Michael Douglas and Sharon Stone. But the movie’s three-day gross of about $4 million was considered slow compared to a usual weekend’s business. Comedies such as Universal’s “Beethoven” and 20th Century Fox’s “White Men Can’t Jump,” with Wesley Snipes and Woody Harrelson, also drew the best of what business there was.

“I’m sure people felt in a psychological state of siege,” said Loews Theatres Chairman A. Alan Friedberg, whose New Jersey-based company operates about 900 theaters in 16 states. “Going out, not only in Los Angeles, was something people chose not to do.”

“People had other things on their mind, and I would think there were (safety) concerns,” said Robert Miller, vice president of marketing for the nationwide General Cinema chain.

But theater exhibitors cautioned that the urban unrest could not solely be blamed for the drop in the box office.

“In the East, this was the first blush of summer, and the weather was not conducive to moviegoing,” said Loew’s Friedberg. He also noted that this time of year is typically the “dog days” of the movie business--a lag time until the major summer movies begin.

Other sources said there was no major new film opening this weekend, which could normally be relied upon to motivate business.

The slow season, coupled with the sudden downturn due to the urban violence, was a setback for the film industry. Box office had just begun to pull even with last year’s level. But exhibitors believe the summer releases will bring a turnaround.

As a result of the violence in Los Angeles County, movie theaters were widely closed due to curfews imposed in the city and surrounding communities. Some were open only for matinees, which were lightly attended.

Grosses in Los Angeles, as a result, plunged severely--in downtown and the Westwood district, almost to zero--where theaters were closed almost all weekend. But the situation in Los Angeles had virtually no effect on box-office receipts for the Orange County-based Edwards Theatre Circuit chain, one of Southern California’s largest chains, according to spokesman Jay Cooper.

“Even if you subtract the Los Angeles market (which includes Orange County), there was a substantial decline across the nation,” said John Krier of Exhibitor Relations Co., a firm that tracks box-office data. Depending upon the definition of the L.A. market by the various companies, it can account for about 7% to 15% of the national box office.

Because of the violence in the city, box-office tracking sources and film studios shut down over the weekend. By midday Monday, normal box-office data was still not available. But there were some estimates.

In first place, TriStar Pictures’ “Basic Instinct,” in its seventh week of release, has accumulated $83.6 million.

Universal’s canine comedy “Beethoven” was No. 2 for the weekend with about $3.5 million. “White Men Can’t Jump” pulled in an estimated $2.7 million and the new film “Folks” came in with about $2.1 million.

“Sleepwalkers” and “Split Second” each generated about $2 million. “The Babe,” “White Sands” and the long-running hit “Wayne’s World” sold about $1.5 million apiece. “City of Joy” pulled about $1.3 million, while “Straight Talk,” “K2” and “Passed Away” did a very languid $700,000 each.

Times staff writer Zan Dubin contributed to this report.