How the Turkey-Syria earthquakes altered the Earth

Authorities are working to understand the extent to which the devastating earthquakes that struck Turkey and Syria last week  have reshaped terrain in the region surrounding the East Anatolian Fault.

Landslides caused by the quakes, which have killed at least 40,000 people and displaced millions morein the past week, have reshaped entire hillsides, effectively blocking roads and mountain passes in unstable areas where the soil contains high amounts of clay. 

"Quakes can also cause underground reservoirs of water to be lost, which can affect the land above. These are the reservoirs that wells and water infrastructure taps into. We don't know if this has happened yet in Turkey and Syria, but it's a possible effect," Patricia Martinez-Garzon, a seismologist at the German Research Centre for Geosciences, told DW.

Anatomy of earthquakes

Martinez-Garzon explained the earthquake was the result of decades of slow lateral movement — around 1.5 centimeters (0.59 inches) per year — between the Anatolian and Arabian Plates, causing tension to build up along the fault. Eventually, the friction grew so high that one of the plates "slipped" past the other, causing last week's quake. 

"Over time — years, decades, or centuries — the friction couldn't sustain the stress anymore and the two plates moved past each other laterally," she said.

This is a mild way of putting it. The lateral move was experienced on the ground as a tremendous magnitude 7.8 earthquake, followed by a second of magnitude 7.5. Both were around 250 kilometers (155 miles) long and cracked the earth's crust to a depth of around 20 kilometers (12 miles). Photos of railways and roads where the cracks shifted the land several meters clearly illustrate this effect.

Satellite images map earthquake zone

Satellite imagery provides a way to observe geographic change from space, offering researchers like Nuno Miranda a bird's eye view of the topographic damage wrought by the quakes. 

Miranda is a mission manager of Sentinel-1, a satellite constellation operated as part of Copernicus, the European Commission's Earth Observation and Monitoring Program.

"We're doing carpet mapping of the region, so providing high resolution (up to a centimeter) mapping of the region every three days," Miranda told DW, adding that his team uses a variety of techniques like radar and optical imagery to create these maps.

The satellite imagery has two main uses. First and foremost, it provides highly detailed and up-to-date information for rescue operations and logistics on the ground. Second, it helps scientists understand the physics of what happened.

Massive land displacement

Miranda's satellites have been capturing striking images of the disaster. They do not contain a trace of a reference to the human suffering on the ground — instead they show a landscape elegantly reshuffling.

The initial quake that struck February 6 created a "left-lateral" shift motion along the East Anatolian Fault line, shearing the land roughly east to west. 

In the image above, the red zones show where the land has shifted eastward up to 3 meters (10 feet) in some areas. The blue zones — the opposing plate — have shifted westwards up to 3 meters, meaning the land has shifted 6 meters in some areas.

"That's really massive, just enormous," said Miranda, adding that scientists are now using this information to create models of the faults to better understand what has happened deeper in the Earth.

"This is both important for managing the crisis and understanding the earthquakes more generally. But this will take time," he said.

Predicting earthquakes impossible

Some countries have earthquake early-warning systems in place. They work by detecting the primary waves released by an earthquake in order to warn people something bigger is coming.

But these systems only give you seconds — enough time to stop a train or shut down the power, but that's it. As for long-term predictions? Impossible, said Miranda.

"What's extremely clear is we have no means to predict earthquakes. This is totally different from volcanoes, which can be predicted to some extent within a few days," he said.

Even now, with aftershocks reverberating across the region, scientists know the area's seismicity is unstable but have no way of predicting where and when further destabilization will occur. 

Sea level changes could track seismicity

Martinez-Garzon is less pessimistic that earthquake prediction is impossible. Her recent paper, published January 17 in the journal Geophysical Research Letters, suggests a link between nearby sea level changes and seismicity rates.

Her research took place in northwest Turkey along the Northern Anatolian Fault. 

"We created very detailed catalogs of seismicity. We saw that seismicity increases during periods when sea levels are rising, particularly in winter and summer when sea level differences range up to a meter," she told DW.

Her idea is that the sea level changes could be a readout of general seismicity in a given region. The higher the sea levels, the higher the chances a big seismic event could be coming. 

It's unclear whether Martinez-Garzon's findings can be applied to the recent earthquake on the Turkish-Syrian border, which took place along a different fault in a different region. But they could prove interesting for the potential early detection of future quakes. 

Edited by: Clare Roth