Satellite images : Earthquake shifts land by several metres

The severe earthquakes in Turkey and Syria have greatly shifted the land surface. This is shown by images from the Sentinel-1 radar satellite. In some places there are faults of six meters.

The earthquake in the border area between Turkey and Syria is one of the most devastating natural disasters that have hit the region to date. The confirmed death toll is already more than 40,000. In addition, thousands of people are still missing.

Huge cracks

In the earthquake area, satellite data help rescue organizations to find their way around and provide assistance. Scientists are already analyzing this data to identify the long-term effects of the earthquake. Scientists at the German Aerospace Center (DLR) have evaluated recordings from the European radar satellite Sentinel-1 and converted them into images.

Cracks in the earth’s surface can be seen over a length of about 250 kilometers. The larger rift in the south is a consequence of the main earthquake that hit south-east Turkey on February 6 at 2:17 a.m. (CET) with a magnitude of 7.7. The second crack, to the north of the first, was created a few hours later by the almost equally strong aftershock. The blue areas represent an easterly movement, the red areas represent a westerly movement. In some areas, the faults are up to six meters wide.

Radar scans the earth’s surface

Both earthquake areas belong geologically to the so-called East Anatolian fault zone. This is where the Anatolian and Arabian plates meet. This creates tension in the earth’s crust, which is discharged in earthquakes. The image shows the displacements of the earth’s surface that caused the February 6 tremors.

The underlying images are from January 29 and February 10, 2023 and were recorded by the Sentinel-1 satellite of the European Copernicus program. It doesn’t have an optical camera on board, but sends radar signals back to Earth and measures how long it takes for their echo to come back to it. In this way, he scans the earth’s surface, day and night and in all weather conditions.

hope of prediction

In the future, radar signals should not only be used to measure the consequences of earthquakes afterwards, but also to make their prediction possible. This is a big task, however, because the voltage below ground builds up very slowly and in millimeters at a time. Although some radar satellites can measure the earth with an accuracy of less than one meter, the images are still difficult to interpret, says Professor Michael Eineder from DLR’s Earth Observation Center.

He likens the surface of the earth to a piece of wood that you try to break: “It can be rotten and it breaks instantly, and it can be elastic and I can bend it very far and build up a very large amount of tension until it breaks.” It’s similar with the earth’s surface: “You don’t know the parameters in the earth, you don’t know when the whole thing will break.” That’s why no earthquakes can be predicted in periods of ten or twenty years, says Eineder.