An extremely strong earthquake occurred in southeast Turkey, near the Syrian border. The data obtained from seismometers that measure ground vibrations caused by earthquake waves show that the event has a magnitude of 7.8 out of 10 on the moment magnitude scale. The seismic waves were picked up by sensors all over the world (you can watch them surge in Europe), including as far away as the UK.

An earthquake caused by energy emanating from a source or epicenter has already had dire consequences for people living nearby. Many buildings were destroyed in both countries, at least 2,000 people died, and there are reports of gas pipelines being damaged, causing fires.

Why was it here?

This region of Turkey is prone to earthquakes as it is located at the intersection of three tectonic plates that make up the earth’s crust: Anatolian, Arabian and African. Arabia is moving north towards Europe, causing the Anatolian Plate, on which Turkey is located, to move westward.

The movement of tectonic plates puts pressure on the fault zones at their boundaries. It is the sudden release of this pressure that causes earthquakes and ground shaking. This latest earthquake probably occurred on one of the major faults that mark the borders between the two countries.

Both of these are ‘thrust faults’, meaning they compensate for some of the motions of plates passing by each other.

“Much stronger” than previous earthquakes

Although the region experiences many earthquakes each year caused by the continuous movement of the tectonic plates, today’s earthquake is particularly strong and destructive as so much energy is released. The United States Geological Survey (USGS) says that since 1970, only three earthquakes greater than magnitude 6 have occurred within a 250-kilometer (155-mile) radius of the area.

With a magnitude of 7.8, February 6 was significantly larger than anything earlier in the region and released more than twice the energy of the largest earthquake ever recorded in the region (magnitude 7.4).

Modern seismologists use a moment magnitude scale that represents the amount of energy released during an earthquake (the Richter scale is obsolete, although it is sometimes misquoted in the news).

This scale is not linear: each step up means 32 times more energy is released. This means that magnitude 7.8 earthquakes release about 6,000 times more energy than the more moderate magnitude 5 earthquakes that typically occur in the region.

We tend to think that earthquake energy comes from a single location or epicenter, but they actually originate from movement in a fault zone. The stronger the earthquake, the greater the area of ​​the fault will move.

For something as large as 7.8, it was probably moving over an area of ​​about 120 miles long and 15 miles wide. This means that the shaking will be felt over a very wide area. An estimated 610,000 people felt strong to strong shaking (enough to cause significant property damage) in an area about 80 kilometers northeast along the tectonic plate boundary.

Mild tremors were even felt in Turkey’s capital Istanbul (about 815 kilometers), Baghdad in Iraq (800 kilometers) and Cairo in Egypt (950 kilometers). Large earthquakes are followed by many smaller earthquakes, known as aftershocks, as the earth’s crust adapts to changes in stress. They can last days or years after the initial event.

In the first 12 hours after the initial tremor, three more earthquakes greater than magnitude 6.0 occurred in southeast Turkey. The first was magnitude 6.7, which occurred just 11 minutes after the initial shock, and there were hundreds of small aftershocks.

Later in the morning, further north, another very large magnitude 7.5 occurred on a different but nearby fault system: the Surgu Fault. Technically, this earthquake was strong enough to be considered a separate earthquake, although it was likely triggered by the first earthquake and would have started its own aftershocks.

Although aftershocks are usually much smaller than the main shock, they can have equally devastating effects, further damaging the infrastructure damaged in the first earthquake and making recovery efforts more difficult. As the people living in the region continue to feel the effects of this powerful earthquake, we can hope that international aid will reach Turkey and Syria as soon as possible to assist the rescue efforts as the aftershocks continue. Source