Prof. Dr. Övgün Ahmet Ercan: Even if it wanted to, the Marmara cannot produce a major earthquake right now

Turkey's leading Senior Geophysical Engineer Prof. Dr. Övgün Ahmet Ercan commented on the earthquake, which he refers to as the North Marmara Earthquake, during a program he attended on Halk TV.

Stating that the 6.2 magnitude earthquake should be called the North Marmara Earthquake rather than the Istanbul Earthquake because it does not only affect Istanbul, Ercan said, "There will be an earthquake 25-30 kilometers away from Istanbul. This earthquake will affect Istanbul, as well as Yalova, Bursa, and Balıkesir."

Here are the highlights from Ercan's assessment:

"The 6.2 magnitude earthquake is the expected North Marmara Earthquake, which should not be called the Istanbul earthquake. Because it has a social impact. It affects the economy and tourism. I especially ask members of the press to refer to it as the North Marmara earthquake.

"THERE WILL NOT BE AN EARTHQUAKE WITHIN ISTANBUL"

This is the correct way to put it. Because there will not be an earthquake within Istanbul. There will be an earthquake 25-30 kilometers away from Istanbul. This earthquake will affect Istanbul, as well as Yalova, Bursa, and Balıkesir.

If we take the Marmara as a whole, 71 percent of the earthquakes that have occurred in the last 2,000 years have been between 6 and 6.5 in magnitude. 71 percent is a very high rate, and one of these occurred yesterday. These earthquakes, meaning those between 6 and 6.5, occur every 30 to 40 years. Those smaller than this occur more frequently. Therefore, it is scientifically extremely beneficial for these types of earthquakes to occur before the North Marmara earthquake we are expecting.

"I AM EXPECTING TWO EARTHQUAKES"

Specifically, I am expecting two earthquakes in the Marmara. If I said I was expecting a single earthquake, the situation would be a bit worse. Because the magnitude of the earthquake I expect is 7.3. But it will divide this into two. It needs to be continuous. We call this the Istanbul branch. The earthquake on this Istanbul branch will rupture right in front of Küçükçekmece. It will rupture towards Kınalı on one side, and towards the west of Büyükçekmece on the other. The expected magnitude of this earthquake is between 6.4 and 6.7.

"BETWEEN 7 AND 7.4"

This earthquake showed us that it is scientifically beneficial. It says that the future earthquake, for which I expect a magnitude between 7 and 7.4 right here, showed us where the earthquake focus will be. We were already expecting the earthquake here.

Why were we expecting it here? There is a fault coming from Eskişehir, the Eskişehir-Thrace fault. It comes and passes through where Mudanya is, creates a junction here, and goes towards Edirne from here. Junction points are very dangerous places for us. It is an intersection point. Those intersection points usually produce earthquakes. And these types of places are usually where energy accumulation is high.

Therefore, it is exactly where we expected, at the depth we expected, 7 to 13 kilometers. Some observatories gave this as 7 kilometers, some as 13 kilometers. Does it make much difference for us? It does not. It ruptured within the granite layer. When the 7.2 earthquake occurs here—which it will in the future—our long-term predictions show that such an earthquake will occur between 2045 and 2065.

"EVEN IF IT WANTED TO, THE MARMARA CANNOT PRODUCE A MAJOR EARTHQUAKE"

Even if it wanted to, the Marmara cannot produce a major earthquake right now. Because the Marmara shows a collective operation. In the 1999 Gölcük earthquake, the Marmara released a tension equivalent to 132 atomic bombs. Now the pocket is empty. 26 years is not enough for the Marmara to accumulate tension again. Because the tension is pushing this region from east to west at a certain rate in this way.

"WE CALL THIS A RIGHT-LATERAL STRIKE-SLIP FAULT"

While pushing this place, the thickness of the earth's crust it will rupture here is approximately 30 kilometers. Imagine it will rupture a 30-kilometer crust along approximately 100-120 kilometers. It will push the mountains, rocks, houses, and cities on top of it by 2-2.5 meters. We call this a right-lateral strike-slip fault. This place is resisting not to rupture with 6 billion gigatons. Now you have to create such tension that it will exceed 6 billion gigatons and rupture. This tension does not exist right now.

When we first appeared in the press after the 6.2 magnitude earthquake, when they asked, 'Professor, how long will it last?', I said that this would be released within 2 weeks. But that did not happen. In other words, almost 90 percent of the tension that was supposed to be released within 2 weeks was released with aftershocks by yesterday afternoon.

"THOSE WITH STURDY STRUCTURES CAN MOVE BACK INTO THEIR HOMES"

The main earthquake occurred here. Normally, after the main earthquake, it ruptures both towards the east and towards the west. Therefore, while all the aftershocks should have gathered like this, they did not see this place at all, and nothing happened here. But all the tremors started to shift towards Istanbul. They came to the front of Sinanoba towards the east. When they came to the front of Sinanoba, they encountered the Büyükçekmece-Çatalca barrier. There is a fault there, and it is also the place where the Istranca massif meets the sea. It stopped there. Now everyone is wondering, is there a creeping slip towards Istanbul?

Then the film would have changed. Will it cross to the Istanbul branch or not? I was of the opinion that it would not cross because the material type is different. In other words, this place is very durable and brittle. This morning, another earthquake occurred right there. Another 4.9 magnitude earthquake occurred. And this place has now stopped its major earthquakes. Actually, I expected this to happen on the first day. However, it was sparse on the first day, and larger earthquakes started to occur today. This means that, just as we expected, there were ruptures on both sides. But most of the tension here shifted towards the East side, the Istanbul side. It shifted, but it stopped there. According to the physical characteristics of the underground, it should not have passed Büyükçekmece, and it did not. But it turned here. That is, it started to produce its earthquakes here. That is, it started to produce them towards the west, towards the front of Marmara Ereğlisi. And it has currently released perhaps 95 percent of its tension.

The effect of the 6.2 has passed. People with sturdy structures can move back into their homes. But I cannot say this. Those with sturdy structures, yes. But I cannot say this. Because this authority lies with AFAD and the Istanbul Governorship. Therefore, I can only state my personal opinion. That is, if there are no significant cracks in the columns and beams of your structure, then you can enter your building."

News Source : 12punto