The strongest quake measured 7.8 on the Richter scale and occurred at a depth of 18 kilometers.

The tremors were felt as far away as Cairo, over a hundred miles away.

At 11:24, a new 7.5 quake erupted just a few miles from the original quake.

In between, several earthquakes above 5 had been measured.

That two such large earthquakes occur within a couple of hours of each other is extremely unusual.

- I can't remember the last time I saw something like this on land of this size, says Björn Lund and continues:

- For the rescue workers, this means an enormous danger.

Houses that have been damaged and cracked can be completely destroyed by the aftershocks.

Tremors above 5 on the scale are real earthquakes, just that.

If we have an earthquake above 3 in Sweden, it will be big news, says Björn Lund.

The earthquake is the worst in Turkey's history since the 1930s.

Aftershocks can continue to occur months or even years after a large earthquake.

The bigger quakes will happen within the next week or two, says Björn Lund.

 In Italy, a tsunami warning has been issued after the night's events.

But according to Björn Lund, the risk is extremely small.

- I don't really understand why people say that.

Here we are talking about a horizontal movement along the crack where the earthquake occurred.

It does not create a major movement in the seabed.

It may indeed lead to bigger waves but not a tsunami.

Turkey is on a pinched plate

It is not possible to pinpoint an exact point for the quake, which occurred along a 20-mile-long fracture zone, says Björn Lund.

Turkey's geological position makes the country very prone to earthquakes.

The country lies on the so-called Anatolian plate, which is sandwiched between three continental plates.

- Turkey is in itself a microplate of its own.

The African continental plate is pushing from the south, the Arabian plate is pushing from the southeast and all around the Eurasian plate is pushing against.

This means that Turkey is constantly being pushed to the west.