For the moment, what matters above all is rescuing every last survivor of the earthquake.

That is made harder by some of the immediate effects of Tuesday's catastrophe - power lines down, road and rail links smashed, water supplies and telephone lines interrupted.

Some reports from Istanbul say even mobile phones can not get through to Izmit.

Blazing oil

Getting food and water to the survivors, and making sure the lack of sanitation in the places they are gathering does not cause an epidemic, is demanding enough.

Smog alert: Liquid gas plant on fire

But in the weeks and months to come Turks will be watching anxiously to see whether there may be longer-term damage.

Concern centres on the Tupras refinery, set ablaze by the quake with its 700,000 tonnes of oil.

The fire is likely to burn itself out by Saturday. But by then it will have poured out large quantities of pollution, into the air, the water and onto land.

Oil industry experts say the outcome depends partly on how much of the crude oil had been refined, as crude burns more dirtily.

They say the smoke will cause pollution and possible health problems for as long as the fire burns.

The oil can be dispersed over a wide area if it gets into the water. But a team from the UK-based Oil Spill Response company is in Turkey carrying booms, absorbent material and other equipment for containing and clearing up the oil.

Industrial havoc

Turkey's pollution is likely to be far less than Kuwait's in 1991. That lasted much longer, and was continually fed by the oil gushing from the wells Iraq had destroyed.

The part of north west Turkey affected by the earthquake contains about a third of the country's industry, and there are reports of extensive damage to factories in Izmit and the surrounding area.

Transport links are in disarray

Greenpeace activists in Turkey are concerned about the potential for further pollution.

"The toxic waste dump at Petkim has large cracks, and the waste which has been dumped there for years is now exposed," said Melda Keskin, a Turkish citizen of Greenpeace's Mediterranean branch.

"So it is possible there is also damage to the nearby PVC factory, to the waste treatment plant and to the incinerator," she told BBC News Online from Istanbul.

"Near Yalova is a chlorine plant, which appeared to be deserted. Next door to it is a factory producing synthetic fibres, where there was some chemical leakage, though it was brought under control."

The pollution left by the Izmit disaster will probably be limited, and possibly reversible.

It may in the end prove less of a worry to Turkey than the continued presence of the Anatolian fault lines. They will not go away.