According to media reports, the death toll from the massive earthquake in Turkey and Syria has risen to nearly 5,000. Many millions of people are affected by the disaster. Talking to us by telephone from a research trip in Oman, Professor Klaus Reicherter of the Teaching and Research Area of Neotectonics and Natural Hazards at RWTH answered some questions about the situation.
What exactly happened in Turkey and Syria?
The East Anatolian Fault is a plate boundary that runs from the Eurasian to the Arabian plate and joins the Dead Sea Transform Fault, running onto Aqaba in Jordan. In other words, it is a so-called strike-slip fault zone. Many strong earthquakes have occurred here throughout history – similar and comparable to the well-known San Andreas Fault. They are pretty well-documented and have claimed many lives. These faults are 1,000 kilometers long and can produce quakes up to magnitude 8, depending on the length of the segment that slips.
Why were there so many tremors in a row?
This strike-slip fault is very long, and the stress drop is practically passed on to the next segment; moreover, magnitude 7.9 is a powerful earthquake with catastrophic consequences – even the aftershocks are still very strong.
Will the situation calm down now until new stress is built up?
There will be aftershocks for some time – I expect it will take about a year until everything "settles down" again.
Were you surprised by the severity of the quake? No, there are certain regularities.
For example, we know of an earthquake in Antioch in 526 B.C. that killed about 250,000 people. Then an earthquake occurred in Aleppo in 1138, killing about 230,000 people – roughly comparable to Haiti in 2010. Consequently, it is a well-known fact that a massive earthquake tends to hit the region every 500 to 1,000 years.
Could people have been warned earlier? Are there any protective mechanisms that could have been taken at all?
No, not really. There are building regulations, the so-called Eurocode 8. If these had been considered and followed, less damage would likely have happened because many houses would have remained standing. But apparently, there has been no interest in implementing the code to date. However, the quake was also very powerful.
What is the situation in Germany? Do we have similar vulnerable areas?
No, the situation is not comparable. We do not have a plate boundary here in Germany or slip-strike fault zones, for that matter. The highest observed magnitude of earthquakes here is around 6.5 to 6.7 – more than an order of magnitude below the Turkey-Syria disaster. This means that much less energy is released in the event of a quake – around 50 times less. Moreover, the periods in which such events recur are much longer, spanning 3,000 to 5,000 years. There are also stricter building regulations, insurance, and the like in Germany, and I would also rate the construction quality more highly here.
Are there generally phases when the Earth’s crust is more prone to earthquakes? Or is it always equally earthquake-prone?
The Earth’s surface is always moving and shifting.
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Reference: ARD/ Erdbeben Türkei und Syrien