Iran-Iraq border earthquake is deadliest of 2017

A huge rescue effort is under way after a powerful earthquake struck Iran's mountainous border with Iraq, killing more than 400 people and injuring more than 7,000.

Teams are looking for survivors trapped in the rubble of collapsed buildings.

The quake is the deadliest in the world this year.

Most people who died were in western Iran in Sarpol-e-Zahab, a town 15km (10 miles) from the border, and other parts of Kermanshah province.
The town's main hospital was severely damaged, leaving it struggling to treat hundreds of wounded people, state TV reported.

A woman and her baby were pulled alive from rubble in the town, Iranian media said.
Many buildings in the town appear to have collapsed, amateur video posted to Twitter by a radio station showed.


Running water and electricity cut out in some cities, and after buildings collapsed people were forced to spend hours outdoors in parks or streets in cold weather.
Many homes in the predominantly Kurdish mountainous area are made of mud bricks and are vulnerable in quakes as large as Sunday's.

"We need shelter," a man in Sarpol-e Zahab told state TV. "Where is the aid? Where is the help?"
One aid agency said 70,000 people needed shelter after the quake, and there were reports that thousands of people were facing a second night in the cold as dusk fell.
The UN said it was "ready to assist if required" in a statement from a spokesman for the secretary-general.

Why is Iran prone to earthquakes?

Analysis by Jonathan Amos, BBC Science Correspondent

Iran is one of those regions of the world that is all too familiar with quakes, and has experienced some very big tremors in the past.

In general terms, the big driver here is the clash between the Arabia and Eurasia tectonic plates. The former is pushing north by a couple of centimetres a year.

In the south-east of the country, the Arabia plate is actually pushing under the Eurasia plate, but in the north-west these great slabs rub directly against each other. The Zagros mountains are a result of all this compression.

Early reports indicate the quake occurred on a thrust fault. This means the crust on one side of the break in the rocks is moved vertically up and over the other side - which fits exactly with this general picture.

Geological agencies now produce immediate bulletins on the likely expected casualties. This modelling work is based on factors such as the size of the quake, population density and what is known about local construction methods. It's inexact work, but the first bulletins suggested this event could produce many hundreds of deaths and perhaps thousands of injured individuals.