Here's a frightening thought; the black rioting in Miami that claimed 15 lives and produced $100 million worth of property damage could be repeated time and time again this summer in major urban centers throughout the country.

The reason: strictly economics -- a case of dollars and cents.

The incendiary spark that might set it off is the lack of jobs. All signs indicate that already massive black unemployment will grow progressively worse in the face of a deepening recession and heavy budget-cutting.

This scary scenario -- viewed by its author as realistic and not for shock effect -- is put forth in a nonemotional, matter-of-fact fashion by a respected black congressman, Rep. Parren J. Mitchell (D-Md.) of Baltimore's 7th District.

And guess what? A top official of the Labor Department -- which is becoming increasingly concerned over rising black unemployment -- does not disagree with this view.

Late last week in an interview -- which Mitchell gave from a hot, sticky telephone booth in the halls of Congress -- the 58-year-old former chairman of the Congressional Black Caucus told me: "Black unemployment is horrendous and time is fast running out. For starters, we need jobs that'll cut black unemployment in half . . . and that at least will give hope to the other half. And such job-hiring programs should be undertaken immediately."

Mitchell warns that if action in this direction is not taken soon, "the potential is there for summer blowups in other cities . . . (and) for extreme difficulties like riots, killings an theft. And I'm talking about major urban areas like New York, Chicago, Detroit, Cleveland, Baltimore and Atlanta."

Harsh talk indeed, but equally harsh is the economic plight of the black labor force.

In the first quarter of 1980, for example, official government figures show the black jobless rate running more than twice the white employment rate -- 12.2 percent vs. 6 percent. But if one were to use the statistics presented by the National Urban League -- which reckons on a partial unemployment rate of 46 percent for the roughly 573,000 blacks now working part time who want to work full time -- the black jobless rate shoots up to about 22.8 percent.

That means that nearly one out of every four black workers -- or 3.1 million of the black labor force of about 13.5 m illion -- are in need of a full week's work.

Disparity is also seen in the black-white pay scales. Last year, the median weekly salary for a working black man was $174, a third less than the white man's weekly paycheck of $233.

The Miami riots were attributed to the freeing of four white policemen accused of beating a black businessman to death. But Mitchell asserts that a strong underlying cause was high black unemployment in that city -- about 17 percent vs. 8 percent for whites.

"What should be recognized -- in terms of the high black unemployment -- is that there are Miamis all over this country," Mitchell said.

The Baltimore congressman tells me he travels extensively. And he's heard the same cry 10,000 times -- from one black after another: "I need a job, man. Get me a job in my own city. I know I've got to do something if I don't get a job."

But instead of listening to that cry, said Mitchell, "we're going the other way. We're trying to balance the budget and this could mean the loss of as many as 200,000 jobs, the bulk of them by black workers."

To remedy the situation, Mitchell urges an emergency infusion of federal dollars into the cities to provide more jobs.

When I said that would be inflationary and eliminate a balanced budget, Mitchell responded: "Let's forget about a balanced budget and try to prevent riots."

In Mitchell's view, enormous pressure should be placed on private enterprise to address itself to the problem of hiring more blacks. "I know we're in a recession and it's difficult to hire across the board, but we ought to prepare for increased black employment now," he said.

Mitchell said this would represent at least one step toward correcting the inequities of the past three years in which private enterprise created a million new jobs a year, and gave the overwhelming majority of them to whites. He noted that in the three-year period, white male unemployment went below 4 percent, while male black unemployment continued to remain around 10 percent. 4

Mitchell offered a couple of other bold proposals for "remedying the black distress in the American economic system."

One was some form of nationalization of a number of basic U.S. industries, such as oil. "When you have an industry (namely, the petroleum sector) making such tremendous profits and it doesn't employ sufficient personnel commensurate with those profits, then something should be done about it," says Mitchell.

The other proposal: The United States ought to examine -- and give some thought to -- the arrangement in Japan where a working relationship exists between business and government. When certain businesses slump, explains Mitchell, the government steps in and subsidizes them, and this, in turn, prevents massived layoffs.

Mitchell didn't address himself to the question, but obviously both these bold suggestions, if implemented, would mean a growing role for government in our daily lives. And that idea is clearly repugnant to most people.

My chat with Mitchell ended on a somber note.

As we move deeper and deeper into this recession," said Mitchell, "more and more blacks will be out of work, and increased numbers of them will wind up on the streets. That'll mean more crime, tougher police reaction to crime, growing confrontations . . . and maybe riots. Why not stop it now with jobs? Do we want to turn the streets of New York, Baltimore and Chicago into another Vietnam?"

I had picked up reports that a worried Labor Department was doing considerably more research on the black unemployment problem. But more analysis is about all it's going to do, judging from Arnold Packet, assistant labor secretary for policy evaluation.

"We are concerned and we're keeping an eye on the situation," says Packer. "But there's not a damn thing we can do about it unless Congress appropriates more money . . . and it's not going to do it. (Congress) won't cut health, defense or Social Security . . . and so job programs are reduced for poor people. Frankly, we'll have less money and so we'll do less.

The official April unemployment rate was 7 percent. And according to the Labor Department, the black employed rate for the month was 12.6 percent.

In blunt talk, Packer tells me that with the advent of a recession and budget cuts, chances are pretty good that black umemployment a year from now will exceed the 13.9 percent black jobless rate of the 1975 recession.

"It's a discouraging time," says Packer, who notes that 250,000 blacks have lost their jobs in the past five months. "People are tired of hearing about the problems of poor people."

Packer shares Mitchell's deep concern that riots in major urban areas are a distinct possibility. "Let's hope that something is done before that happens," he concludes.