Do earthquakes threaten Iran's nuclear facilities?



A magnitude 7.8 earthquake has rocked Iran, a week after another major quake struck the country.

How bad was today's earthquake?

According to the US Geological Survey (USGS), the quake struck at 15:14 local time in Sistan and Baluchestan Province in the south-east of the country. A magnitude of 7.8 marks it as a major quake. Tremors were felt as far away as India.

"The earthquake was probably a result of normal faulting within the Arabian plate as it is subducted under the Eurasian plate along the Makran coast of Iran and Pakistan," says Brian Baptie of the British Geological Survey.

So far it is unclear how many people have been killed; the BBC suggests at least 40. The USGS says the focus of the quake was 82 kilometres below the surface. Such deep quakes are less damaging than shallower ones.

 

Sistan and Baluchestan Province is a particularly poor and desolate part of Iran. It is sparsely populated, with many people living in vulnerable mud-brick houses. Many of these buildings have apparently collapsed. The remoteness of the area means it could take days or weeks to find out how many have died.

Is this linked to last week's earthquake?

Today's quake comes a week after a magnitude 6.3 quake that struck Bushehr Province in the south-west of Iran on 9 April. Although it was a smaller quake, at least 37 people were killed.

The two quakes were 1000 kilometres apart, says seismologist Jana Pursley of the USGS. "I wouldn't call them related right now," she says. Iran is a tectonically active country, and earthquakes are common.

Is there a danger to Iran's nuclear facilities?

As far as we know, today's quake was far from Iran's nuclear facilities. Many of these are in the centre of country, particularly near the capital Tehran, or in the west.

Last week's south-western quake occurred close to Iran's only nuclear power station, in Bushehr. Iranian officials said that the plant was undamaged and no radioactive material escaped.

Nuclear power stations generally cope quite well with earthquakes, says Michael Bluck of Imperial College London. They are built on thick slabs of concrete that cushion them, and backup generators are used to keep the reactors cool in the event of an accident.

Iran does have other nuclear facilities but little is known about them.

Didn't the Fukushima disaster show that earthquakes are a risk to nuclear power stations?

Fukushima rode out the earthquake safely but the Japanese disaster was a reminder that nuclear power stations are vulnerable to tsunamis.

When the Tohoku earthquake struck Japan in 2011, the Fukushima Daiichi nuclear reactors automatically shut down. The real problems started when a massive tsunami swept over the sea wall. This knocked out the backup generators, leaving the reactors without their cooling systems. The reactors then overheated, there were explosions, and radioactive material escaped.