From all outward appearances, Tehran looks normal to the eyes of a casual observer - over-crowded, traffic-congested, noisy and frenetic in a way that almost seems to affront the serene grandeur of the snow-capped Alborz mountain range overlooking the city from the north.

But beneath the appearance of typical big city life are indications of a severe discloscation of the economy in the weeks ahead, possibly a drastic downturn in the quality of life here.

As usual British-made double-decker buses swerve precariously through traffic bedlam during the rush hour that seems to last all day. Automobiles pour into intersections at breakneck speed, ignoring stoplights and traffic policemen, until all of the ears are clogged in a hopeless tangle of vehicles amidst a cacophony of horn blowing.

Motorcycles speed along in the middle of crowded sidewalks, narrowly missing pedestrians, their drivers shaking their fists and cursing as if it were their territory that was being violated.

The madcap milieu that strikes a visitor almost as collective nose-thumbing of everyday law of society could seem like mild symptoms of anarchy, or least the manifestations of a city populace painfully frustrated over months of civil turmoil and, as a result, taking it out on one another.

Except that this is the way Tehran usually is, and its flavor - on the surface - has not changed much with the advent of a crisis that is threatening to end 25 years of authoritarian rule by Shah Mohammad Reza Pahlavi.

But the outward appearances of normality are deceiving. They create a sense of well-being that hides the steady erosion of the foundation upon which the shah's dream of reviving the great Persian Empire is built - Iran's economic stability.

Perhaps contrary to the perception of the outside world, there has not been the kind of visible disintegration of social fabric that comes to mind with suggestions of near anarchy - or at least civil turmoil.

Masses of people are not running amok in the streets everyday, and when some do, their embittered theater of protest is just as likely to go unnoticed for the moment elsewhere in Tehran, because this capital city of 4.5 million sprawls like Los Angeles and its geography swallows up demonstrations.

Heavily-armed Iranian army troops and riot police can pour into a neighborhood and a little protesters with water cannon and tear gas, but six blocks away there will be no evidence of it, and people 16 blocks away may not even hear about it until the next morning.

Most stores are open and functioning normally. Public transport, never adequate despite the billions of dollars that flowed out of Iran's oil-fed development boom, still works. Garbage is collected on time, electricity flows without interruption and the telephone system - with the exception of a woefully inadequate overseas exchange - makes Tehran seem like a communications marvel compared to Cario.

But after four days, the nationwide oil strike shows no sign of coming to an end. The army's dual strategy - exerting pressure on those who refuse to work while providing protection for those who want to work but are afraid - does seem to be assuring Iran of at least enough supply to meet its domestic consumption for the time being.

Beyong the oil strike is the constant debilitation of the combined effects of a highly organized subversion of Iran's economy by an increasingly sophisticated anti-shah National Front, and the government's apparent acceptance of a policy of appeasement.

"The opposition is getting in wherever it can and is turning the economy into a shambles. It is the fruit of good organization, tied in with the general trend of dissatisfaction of the workers and the helplessness of the government," said one economic analyst.

Despite official denials, Iranian Finance Ministry officials concede privately that labor unrest has premeated the country's entire industrial base.

Iranian government economists should know, since about half the Finance Ministry's employes are on strike and crowds of National Front supporters have recently staged demonstrations inside the ministry headquarters, running up and down the corridors, shouting "Death to the Shah."

The government's water board employes also are striking and fears are growing here that there may be disruptions of water service, in addition to possible power shortages because of the reduced supply of natural gas used to fire Iran's generating plants.

Bank strikes, coupled with scores of banks that closed because of riot damage, have created a shortage of bank notes, prompting some Iranians to begin hoarding rials. A wry sidelight to the bank problems was the appearance this week of bogus 10,000 rial notes bearing the likeness of Ayatollah Khomeini, exiled Shiite Moslem leader who is directing the anti-shah activities from a French village.

Some economists are predicting 50 percent inflation in another three or four months, not only because of the impact of the loss of oil revenue - which, accounts for 60 percent of Iran's gross national product - but because of spiraling wages resulting from quick settlements made by a besieged government.

Workers in Iran do not conduct strikes as Westerners know them. There are rarely walkouts because strikes are illegal and there are not organized unions.

Workers go to their jobs and receive pay, but simply do not work, or conduct "work to rule" actions so exaggerated that production is practically nil.

Many factories, while technically open, reportedly have become little more than meeting places for disgruntled workers to hold political meetings and discuss new demands.

Some of the demands that have been accepted are extraordinary: paid meals, paid transportation to work, rehiring of employes fired during the last 15 years no matter what the cause, pay for travel time to work, and dismissal of some supervisors.

The strikers have also made political demands, unmet as yet, such as an end to martial law and severing the dependence of the Iranian economy on the value of the dollar.

The demands that have been met, in some cases, include the firing of foreign employes. Officials say this has brought some factories to a virtual standstill, and cut productivity of others in half.

Trying to predict events in Iran today is folly, and nobody knows for sure whether the "rolling disaster" of Iran's economy, as one political observer put it, can be reversed.

The government's hope that the shah's policy of concession making will calm the unrest long enough to hold elections in eight months has not flickered out altogether. If it had, presumably a military government would have been installed by now.

But the opposition show little evidence of letting up on its way of attrition against Iran's economy. The result, in the view of most responsible observers here, is that conditions will get worse before they get better.

Wire services reported the following :

Iran's government radio reported that police and anti-shah demonstrators clashed during demonstrations in Babol, 200 miles northeast of Tehran. One demonstrator was killed and another was wounded, the radio said.

A National Iranian Oil Co. spokesman said, meanwhile that oil production, cut considerably by the strike, had increased somewhat but still was down by more than half.

Brokers in London said Iran's biggest oil terminal, at Kharg Island, had resumed pumping crude oil into tankers, but that 33 supermarkets are backed up in the area awaiting full resumption of pumping.