Recent Earthquakes Discussed on the Anniversary of August 17th
Aug 17, 2017

ITU Faculty of Mines and ITU Eurasia Institute of Earth Sciences faculty Prof. Dr. Celâl Şengör and Prof. Dr. Hans Thybo provided information about earthquake studies at ITU.

18 years have passed since the earthquake on 17 August 1999 at 3:02am with a magnitude of 7.4 that lasted 45 seconds, starting in Kocaeli, Gölcük and affecting the entire Marmara Region, even İzmir and Ankara. According to official figures, hundreds of thousands of houses and offices had been damaged. 17, 480 people lost their lives and 48,901 were injured. A lot of research has been conducted at ITU on the part of the North Anatolian Fault Line that caused the August 17 earthquake in the Marmara Sea. ITU is one of the biggest contributors to this work in Turkey. At this point, many questions were posed to our faculty members, everything from the earthquake research which everyone was curious about to recent earthquakes that have occurred. Scientists also listened to the precautions citizens should take when giving information about earthquakes.


"ITU has always been the leader"

The second Turkish elected member of the Austrian Academy of Sciences, ITU Faculty of Mines and ITU Eurasia Institute of Earth Sciences faculty, Prof. Dr. Celal Sengör, said the following:

"In the past 18 years, Turkey has made great strides in earthquake research. The most important burden of this has been borne by two institutions: ITU and the Kandilli Observatory and Earthquake Research Institute. All sea surveys in Marmara have been organized by ITU and a complete network of international collaborations have been established. As a result, the Marmara is one of the world's best, if not most, well-known inland seas. The contribution of the Kandilli Institute has been in the area of instrumental seismology. Besides these two institutions, the MTA and Disaster Affairs also contributed. But ITU has always provided the leadership."


There is nothing to worry about

Prof. Dr. Şengör who evaluated the recent earthquakes in the Aegean region, especially Bodrum, expressed the following:

"The earthquakes in Bodrum are the result of the great normal fault of Gökova, which is one of the faults belonging to the Aegean stress system which forms the western part of Turkey. One cannot think of this fault as a single surface. There are many large and small normal faults parallel to it. The big earthquake has triggered them. According to earthquake records at the disposal of our country, since the 15th century, the area where earthquake activity is most concentrated in the Aegean region is from the Big Menderes Valley to Edremit. Further north, obviously, it enters the area of the North Anatolian Fault. There are not many earthquake records in the vicinity of Gökova. This does not mean that there should be. But according to what we have, it's been quiet there for a while. Now the Aegean is stretching north-south at a speed of 1.5 to 2.5 cm per year. So Marmaris is moving away from Istanbul at this rate. This departure takes place with the movement along the normal faults that border the eastern-western extensions of the Aegean region (from north to south to the Edremit-Merzel Strait, Bakırcay-Simav, Alaşehir, LittleMenderes, Big Menderes and Gökova). This departure takes place with the movement along the normal faults that border the eastern-western extensions of the Aegean region (from north to south to the Edremit-Merzel Strait, Bakırcay-Simav, Alaşehir, Küçük Menderes, Büyük Menderes and Gökova). These movements also cause earthquakes from time to time. The greatest of these earthquakes will barely be a 7 magnitude (sometimes a little more). It is usually 6.5 or less. An earthquake of 6.5 means a 2m displacement according to the American Geological Survey's statistical evaluations. If we take the slopes of the normal faults roughly as 45 °, then 2m corresponds to the hypotenuse of an isosceles triangle, which corresponds roughly to a horizontal extension of 1.5 meters. Suppose that the annual growth in the Aegean is at most 2.5 cm. So in ten years, it will be 25 and in one hundred years, 250 cm. This is about 0.25 m in a hundred years. Take three of the largest Aegean earthquakes in the last century, Gediz, Alaşehir, and Söke. These earthquakes alone have already filled a centuries’ quota for Western Anatolia. Because the Bodrum Earthquake is further west than these, it is literally extra. After this, in order to have an earthquake of this magnitude here, the Aegean must accelerate, which is not possible. Therefore, after the breaks from the fracture, the surrounding faults will release the accumulated tension on them. This means that earthquakes like 5+, 4+, 3+ will last for a while, so I do not see a situation that is very alarming."

Do not trust every media news

Prof. Dr. Şengör provided the following warnings to his fellow citizens:

"They should be careful about a house being durable, and that if they are going to buy or build new homes, that they are certain to consult a geologist and an earthquake engineer. The geologist for the ground, and the earthquake engineer for the building. And they absolutely should not take things portrayed in newspapers and televisions seriously. There, those who claim to be “scientists” or “experts” have nothing to do with these matters. They should look at who is providing input, if it’s ITU or the Kandilli Observatory, then it’s okay."


Hans Thybo: Earthquakes that occur in the sea trigger tsunamis

ITU Eurasia Institute of Earth Sciences faculty, Prof. Dr. Hans Thybo, who is one of the most recognized names in the field of earth sciences, expressed the following about earthquakes in Turkey:

"Turkey has been exposed to severe earthquakes so far due to its location. From a geological point of view, Turkey has a very young and complex structure geographically. While the Arabian plate pushes eastern Anatolia towards Eurasia in the north direction, the big land part of Anatolia turns west and the Aegean Sea line turns south. The North Anatolian Fault Line is the basic geological structure that causes this movement and serves as a border between Anatolia and Eurasia. A large part of Anatolia is located between the lithospheric plates of Eurasia, Africa and Arabia. Observations point out that the earthquake movements of the North Anatolian Fault migrated westward in the 20th century with large earthquakes between 1939 and 1944, which took place in Eastern and Central Anatolia. The last earthquake in Izmit in 1999 caused a lot of damage. For this reason, the next earthquake on the North Anatolian Fault is expected to occur in the Marmara Sea, possibly near Istanbul. What can we do at this point? We can build earthquake resistant houses. It is very important to be in communication with specialists. Let's not forget that the earthquakes that started in the sea triggered tsunamis. Let's be aware of the risks."