Will Istanbul Have Another Earthquake: Expected Great Istanbul Earthquake

A growing concern: The Great Istanbul Earthquake. One of the most devastating earthquakes in history is expected to happen in Istanbul. An earthquake is expected that will stab like a dagger in the heart of almost the whole economy of a country that can be considered large, and perhaps guarantee that nothing will be the same. As the TV channels make the earthquake subject get over the ratings, the scientific side of the work is ignored as usual. An earthquake, possibly a “mega earthquake,” is presented as if it were magazine news. In this article, we will try to show you the scientific sides of the subject and explain why experts expect a major earthquake in Istanbul.

The expectation of scientists for this great Istanbul earthquake is a natural process that is completely based on scientific foundations, which can be explained with basic geology knowledge, in which no man-made product can directly interfere. Like all earthquakes that have existed so far, the expected major Istanbul earthquake will be an extremely natural event. In this article, we will show you all the details. The fact that the constant magnitude of this earthquake is mentioned is not due to the fact that Istanbul is a metropolis or that waiting for an earthquake in Istanbul is a more popular topic. It is due to the fact that the expected big earthquake will indeed be in Istanbul.

The Science of Earthquakes: Plates and Fault Lines in Istanbul

First of all, it is necessary to explain what the earthquake and fault line means. The only reason for all tectonic activity on Earth is that the Earth is a melted ball of fire. As we know, even if the Earth is a planet, it can be called a “ball of fire” due to its internal structure. However, the reason why we do not feel this is because the outer layer of the Earth is colder than inside, and the thin, “shell” on the outermost part of it, which we walk on, has cooled.

All the continents and oceans we know of are located on this thin crust. But don’t be fooled by this “solid” view of the Earth: The crust layer is 5-10 kilometers under the oceans and 30-50 kilometers under the continents; however, the radius of our planet is 6371 kilometers! In other words, the crust we are on is in the word “nothing” compared to the rest of the Earth. Let us explain it this way: When we consider the Earth, the ratio of the cooled part and the uncooled part is even less than the ratio of the peel of an orange to the fruit part we eat! So our planet has a very thin crust! Magma under the crust is a solid substance (plasma) close to liquid.

There is a large amount of heat in the hot part of the center of the Earth. This high thermal energy even causes magnetic fields and electric currents to occur! The mainland is not one piece and consists of a large number of plates (we’ll get back to this shortly). What you need to know here is that the land under our feet “floats” on this molten structure. The melt flows called convection currents caused by the molten material in the mantle cause the parts of the shell (plates) just above it to move in different directions. Convection currents are the cyclic/circular motion of magma under plates. With the movement of plates containing oceans and lands, everything on these plates also moves slowly. For example, the Anatolian plate (or the Eurasian plate in general) also is pushed from the south by the Arabian plate and the African plate.

The Tethys Ocean is the name of the ocean formed in the triangular, large, and narrowing space between the continents Laurasia and Gondwana, which formed after the disintegration of the Pangea Supercontinent. Anatolia emerged from within this ocean, and this uplift process has traditionally been studied in two stages: Paleo-Tetyan Phase and Neo-Tetyan Phase. During the latter, approximately two oceans form and begin to diverge: Bitlis Ocean and Zagros Ocean (sometimes known as Bitlis-Zagros Ocean).

Movement of the Anatolian Plate and Bitlis Ocean

This ocean disappeared between 5 and 11 million years ago, when the Arabian Plate, which broke off from Africa in the Late Miocene, moved upward, to the north, and closed this ocean. When this plate could not find a place to go, this time it started to swell and formed the mountain ranges in today’s Southeastern Anatolia. Already, the formation of mountains occurs with the breaks and twists that occur as a result of the plates colliding with each other. We see another example as a result of the northward movement of the African plate: this movement formed the Taurus Mountains. After the movement of the Arabian plate for a certain period caused the closure of the Bitlis Ocean and the formation of mountain ranges, this time it started to push Anatolia to the west.

Meanwhile, Anatolia broke off and gained a movement in the west direction. This movement, which lasted for 4 million years, divided Anatolia into two in an east-west direction. This fracture, which starts from Bingöl and reaches the Aegean Sea, is called the North Anatolian Fault Line. The phenomenon named fault line is the rupture of the earth’s crust, as we have just mentioned. These lines are “fractures” that occur in the earth’s crust as we know it! Since these fractures are empty, water fills into it, the water goes down to the hot rocks with magma, becomes hot and as it warms up again, it gushes up like hot water vapor from the teapot. We also call them hot springs. There are hot springs in all cities where the North Anatolian fault passes: Erzincan, Reşadiye, Havza, Adapazarı.

Turkey moves westward average of 20 millimeters each year. Of course, because both surfaces of the fault line are rough, sometimes they get interlocked and cannot go the way it should go. For example, if the fault, which has to advance 4 meters in 200 years on average, cannot progress, and if the installed indentations and protrusions cannot withstand 200 years of accumulation, it will break in an instant and this causes tremors. Earthquake is exactly that; When the 4-meter movement that should have been in 200 years occurs within a few seconds, we call it an earthquake. Because this extremely fast movement, although still extremely slow for the earth’s crust, creates shocking effects for the organisms that live on it. We perceive these shocks as earthquakes.

In other words, earthquakes cannot be produced by technological means; It is formed as a result of massive movements of huge lands, such as your fingernails getting caught on your clothes and breaking suddenly as a result of your application of force. No technology produced by man can give direction or shape to this. The upper part of the North Anatolian Fault Line is the Eurasian plate, the lower part is the Anatolian plate. Recall that the fault lines are the regions between these plates. The upper part is more geologically stable and much more difficult to move. For this reason, the Anatolian plate is under great stress due to intense pressure from the south and moves westward.

As we mentioned, sometimes the fault line gets stuck and the plate that needs to move cannot move because it is pushed. The pressure increases and suddenly the interlocking surface of the fault breaks and the fault “throws itself forward” 2-5 meters. In other words, the plate takes the 2-meter path, which must travel slowly in 100 years, in 30 seconds, and this causes great jolts. This is exactly what happened at 03:02 on the night of August 17, 1999. The throw was about 4-5 meters and this movement took about 45 seconds. Just as snow accumulates on the branch of a tree, it accumulates, it accumulates. Then it breaks suddenly to crack and shakes the tree very hard. And the earthquake is the geological version of this.

Earthquakes Coming Rapidly to Istanbul from the East of Anatolia

Don’t be fooled by this title. The word “rapidly” is often used a little differently from everyday life in sciences such as geology, evolution, climate, and paleontology. Normally, an event can be “fast” for a few seconds, minutes, hours, or even days. However, in such sciences, “fast” is meant for a few decades, centuries, or millennia (thousand years). Sometimes events that take place over millions of years can be referred to as “rapid”, as they normally occur much faster than the course of that event. Therefore, it is useful to pay attention to how the word “fast” is used when talking about earthquakes and earth science.

This brings us to the main point. Coaxial earthquakes of logarithmic magnitude sometimes occur on a fault line (not every earthquake series has to be this way!). It can be said that these earthquakes occur periodically. In other words, a major earthquake happens at one end of a fault line. After a few decades, big earthquakes occur again a little ahead, then a little further, then a little further. This process goes on like this and it is seen that the earthquake moves like a train along a fault line at certain intervals. One of the most obvious examples of this kind of progress used in textbooks is seen on the North Anatolian Fault Line. Another famous example is the California Fault Line.

Therefore, those who maintained that technology is a product of the earthquake in Turkey and the United States holds responsible for this technology, as the country itself should explain exactly why that same earthquake sequence. But of course, this is a completely different matter of discussion. We want to make an important caveat here: Fault lines should not be considered as a single whole! Like nothing else in the Universe, fault lines are not perfect structures. Fault lines are like matchsticks spliced ​​end to end. They are piecemeal; however, those parts constitute the whole of the fault line. Each piece that forms the fault line like a “matchstick” is called a segment.

When an earthquake occurs, only one segment breaks, but not the entire fault. One of the clearest examples of this is the 17 August 1999 earthquake. In this earthquake, only the Izmit segment of the Anatolian Fault Line was broken. Since one end of the segment is in Yalova and the other is in Adapazarı, the quartet Yalova – Gölcük – İzmit – Adapazarı experienced the real shock in the earthquake. It is precisely for this reason that the 17 August earthquake is known as both Gölcük, Yalova, İzmit and Adapazarı Earthquakes.

History of Earthquakes in the North Anatolian Fault Line

As for the earthquakes on the North Anatolian Fault. In fact, we need to talk about a large number of earthquakes; However, compared to what we will examine, earthquakes over 7 will be handled in this process in order to make the subject short. Examining the earthquake history of the North Anatolian Fault Line will clearly reveal why a giant earthquake is expected in Istanbul.

  • 1939 Erzincan Earthquake – Magnitude: 7.9

In 1939, the Erzincan earthquake occurred at the tip of the North Anatolian Fault. The magnitude of the earthquake was 7.9. As Erzincan became the center of the earthquake, most of the energy in the Erzincan segment was drained. Where did this energy go? Some of this energy was transformed into vibration, making the earth vibrate and scattered into space. Some of them were deposited in the segment just to the west, as the fault line was twisted in an east-west direction. This meant disaster for the west of Erzincan. In short, it transferred the energy on the segment to the segment just to the west, just like a relay race.

  • 1942 Niksar Earthquake – Magnitude: 7.0

3.5 years had passed since the energy transferred from the Erzincan segment emerged in the Niksar segment in the west. The year was 1942, Niksar was destroyed by a 7.0 earthquake. Of course, the Niksar segment continued with the same flag game and gave its energy to the Tosya-Ladik segment just west.

  • 1943 Tosya-Ladik Earthquake – Magnitude: 7.2

A year had passed since the Niksar earthquake, the year was 1943. Tosya-Ladik was shaken by a 7.2 earthquake. The energy in this segment was also transferred to the Gerede-Bolu segment to its west.

  • 1944 Bolu-Gerede Earthquake – Magnitude: 7.2

In 1944, Bolu-Gerede shook with a 7.2 earthquake. Energy again fled westward as usual. Because the Arabian plate was constantly pushing the beautiful Anatolia to the west.

  • 1957 Bolu-Abant Earthquake – Magnitude: 7.1

It had been 13 years that the Bolu-Abant segment, adjacent to the Bolu-Gerede segment, was broken in 1957 by an earthquake of 7.1 magnitudes.

  • 1967 Adapazarı Earthquake – Magnitude: 7.2

When the calendars showed the year 1967, the chain of earthquakes that progressed like a tsunami reappeared in Adapazarı. Adapazarı was destroyed by a 7.2 earthquake.

  • 1999 Izmit Earthquake – Magnitude: 7.4

Again, there was no earthquake for many years. The earthquake destroyed the Izmit segment in 1999 with an earthquake of 7.4.

Why Istanbul? Why now? Why Great Earthquake?

The energy released after each earthquake is modeled and mapped by geophysical engineers. There is no energy left in the earthquake segment, and there will be no major earthquakes in that segment for many years again. Of course, the earthquake is not something that ends, as plate movements continue; But big stutters and breaks, once they happen, are not repeated for a long time. But each time most of the energy is shifted to the neighboring segments of the broken segment.

The reason experts are waiting for a big earthquake in Istanbul is that these earthquakes are over 7. The reason we are so sure that a big earthquake will hit Istanbul is that the series has not surprised scientists once since the 1900s. The reason is that Istanbul is located in the next segment. No geophysical modeling done shows that these fault diffractions will turn east again. On the contrary, the point where almost all analyzes meet is common: Currently, stress is accumulating exponentially in Istanbul, and this stress becomes more and more with each passing year.

Approximately 12 bars of energy accumulated in Düzce migrated to the east with the Düzce earthquake. And where is the energy accumulated in Gebze? That energy is in the segment of Istanbul. Unfortunately, we have to face the reality: It doesn’t have much life left, there will be an earthquake soon. It is no use deceiving or consoling ourselves, we should start looking for solutions, we are even late. For example, we can say this clearly: we do not expect a serious earthquake, at least geophysically, in Izmit, Adapazarı, and Yalova in the next few centuries; However, we strongly remind you that predicting earthquakes (especially in the near term) is almost impossible and therefore people living there should never let go of caution.

But we can say that Istanbul and its immediate surroundings are on the edge of a knife and are the most dangerous areas; therefore, the risk factor of other regions is smaller next to Istanbul. The Istanbul segment has no salvation. Many experts expect this earthquake between 2019-2021. Even according to the loosest calculations, this period will not be after 2029-2031. Therefore, our advice to the people living there is to get away from the Marmara coasts. Especially those living on the coasts of Pendik, Maltepe, Kartal, and those living on the shores of Zeytinburnu, Bakırköy, and Avcılar should migrate further north if they will live in Istanbul.

In the 17 August earthquake, Avcılar suffered more, although it was farther from Zeytinburnu, Kadıköy, and Bakırköy, to the focal point of the earthquake. The reason is not that the Avcılar’s ground is not solid, as some reports have claimed; It was the collision of the reflected and refracted earthquake waves in Avcılar completely by chance. In other words, it is not clear and unpredictable where the waves will collide. However, statistically, this meeting is more likely to take place on the coast. For this reason, it is useful to stay away from the coasts.

The Difficulties of Interpreting the Expected Great Istanbul Earthquake

We mentioned that the North Anatolian Fault Line starts from Bingöl, crosses Istanbul, and reaches the Aegean Sea (Saros Bay). We have said that there are dozens of segments along this line. An interesting fact is that only two of these segments have not been broken in the last century: One is the Yedisu segment, the other is the East Marmara segment, which we are currently discussing, just below the islands.

As the author of this article, I have brought together many independent studies, including those I mentioned in this article in my thesis about the expected Istanbul earthquake. I cannot say that I came up with something new as a result of my research; however, in independent studies, I discovered that some previously unrelated pieces fit together like a puzzle. We’ll talk about this a little bit now and provide examples of a deeper analysis. There are two difficult aspects of interpreting Istanbul’s earthquake hazard, let’s talk about this first:

The first is that the fault that will affect Istanbul is under the Sea of ​​Marmara. It was not known where the fault under the Sea of ​​Marmara passed until 1999! Its discovery was made after the 1999 earthquake. In fact, the North Anatolian Fault splits into three branches after Adapazarı. The northern branch goes from Izmit Gulf, the Islands, and Florya offshore and reaches Tekirdağ. This branch is the structure that creates the Islands and the Gulf of Izmit … The middle branch passes through the Edremit gulf and goes to the Dardanelles via Bandırma. These two fault branches are the faults that make up the Marmara Sea. In other words, as the north and the middle arm move away from each other, there is a collapse in between and the sea is formed by filling with water. Today we know this sea as the Marmara Sea.

The second difficult part stems from the inability to access the sources about the old Istanbul earthquakes. There are actually resources. But because of the alphabet change and even the change of language over time, these ancient records are difficult to understand. For example, during my thesis, I found a Turkish source (a report prepared by the rulers of the time) on the 1884 Istanbul earthquake. However, this report, written 130 years ago, cannot be understood today without an interpreter. Since many researchers do not bother to have these translations done and do not know the language, it is very difficult to know where and how to access these sources; Accordingly, many findings that may guide the studies can be ignored. It is a fact that we need more translations in this field and transfer of old data to the digital environment and to make it available to the public.

Analysis of Ancient Earthquakes

As we mentioned above, the fault map under the Marmara Sea has just been made. We compile earthquakes from history books and compare them with today’s fault map, and by looking at the damage and impact area of ​​that day, we determine which earthquake is on which branch. We have six chapters on the Marmara Sea fault map. To give an example from the analysis, it can be said that a chain of thought has been passed through:

This or that earthquake happened in these six parts. For example, the earthquake that took place in 1719 affected Istanbul, but it had a greater effect on Kocaeli than Istanbul. In other words, this earthquake has only been in the gulf segment. There were people who died in Istanbul in the 1766 earthquake, but the earthquake caused more damage in Edirne. This means that the earthquake is in the western Marmara segment. Here we list all the earthquakes of these six regions (segments) in a tabular form. Then we enter the dates in these lists and find these pieces broken every few years. Considering more than 7 earthquakes:

In the bay segment; Earthquakes occurred with an interval of 189, 235, 321, 202, 221, 280 years. In other words, it was not broken for 280 years before 99 earthquakes. 14 years have passed. The bay piece will likely remain unbroken for another 200 years. In other words, the gulf period is around 200 years on average and yet in its 14th year. This means the area is currently safe from danger. From there, we come to the Adalar segment. Between the earthquakes, there are 432 years, 520 years, and 504 years. As it is now in its 504th year, it is in the last stages of its cycle. That is why the Adalar fault is very dangerous today! It has a load on it that has accumulated over a very long time. Even if we ignore the energy that the Körfez fault loaded on the Adalar fault after the 99′ earthquake, it has already reached the end of its period. So anyway, a break from this benefit is expected. This break will cause great destruction.

Similarly, the average period of the fault off Florya is 250 years and today this fault is in its 259th year. In other words, this region is also broken, in a situation that will break. The other fault branch off Silivri, that is, the period in which the fault made a northward curve in the Marmara Sea, is about 250 years and that is today in its 246th year. In the West Marmara fault, the period is 250 years and the current period is 246 years. Finally, the period of the part around Gaziköy is around 270 years. But it’s calm there. It is in the 101st year of its period because it was last broken in the 1912 earthquake. In other words, it is a piece that does not require us to wait for an earthquake anymore. There is an average of 170 years ahead of it.

The four parts running from the Islands to Gaziköy have either filled their period or are about to fill. As we mentioned in particular, the Adalar fault is in a very dangerous process. If we had known the fault network beneath the Marmara Sea in more detail, we could have done a much better analysis. Still, the point reached today is considered very good compared to 10 years ago.

Richter and Gutenberg Analysis of the Great Istanbul Earthquake

The above section was just a study. It was the combination and interpretation of the science of history and geophysics. Also, when we use the logarithmic formulas developed by Gutenberg and Richter to take the exact data related to only geophysics and give the periods and repetition numbers of earthquakes, we obtain data that exactly corresponds to the above results. Likewise, in this completely independent study, the Adalar fault, Middle Marmara and Northern branch, and West Marmara carry a high earthquake risk. To give the exact numbers, it’s 0.04 percent in the bay for 2017. So it’s close to the impossible. 79 percent in Adalar, 63 percent in Central Marmara, 66 percent in North Bend, 65 percent in West Marmara, and 0.002 percent in Gaziköy. When we examine the historical data separately, the four parts in the middle seem very dangerous, and Körfez and Gaziköy seem safe.

Putting this aside and using the relationship of Richter and Gutenberg, the inventor of the Richter scale, we make calculations on the completely new generation, precise, instrumented earthquakes, and again we see that the Körfez and Gaziköy faults are safe and the other four faults in the middle are very dangerous. While the risk analyzes for 2017 gives this result, when we consider this for 2025, the risk in the island’s fault is 85 percent. The other three dangerous pieces are increasing at the same rate. There are many small fragments between these two faults. Since 484 AD, 34 earthquakes have caused damage in Istanbul. In order to make an accurate analysis, we need to know which of these earthquakes occurred in which branch or in which parts between these two branches.

If we could examine the bottom of the Sea of ​​Marmara meter by meter, our job would be very easy. This is the first difficult part of the job. We don’t have the technology to do this. It cannot be said that we are in cooperation with countries that have the technology. Fortunately, these analyzes are taken seriously as danger bells start to ring. It is precisely for this reason that American, French, German, and Italian teams, which you hear on the news, dive into the Sea of ​​Marmara and make analyzes. They take samples from the fault line, make measurements, examine the line, and determine possible risk factors. In this way, they hope that we can make it easier for us to predict the earthquake and reduce the loss of life and property.

When we try to predict new earthquakes by using a functional relation called “Student T-Test”, which is generally used in statistics science, which is independent of these two studies, even geophysical, we reach the same percentage results for these six regions. In other words, in these three studies, risk points to the same points equally. The area that gives a red alarm is the Adalar fault. If we add to this that the 99′ earthquake directly loading the Adalar fault, the result looks even more grave.

But the worst part of the job is that when the Adalar fault is broken, its energy has already filled its rupture period, it comes to the brink of breaking and will give its energy to the middle Marmara fault. It also broke in a short time and gave its energy to the north bend, and again to the west Marmara fault after a short time. This means that there will be at least 4 major earthquakes in Istanbul that will affect all Marmara shores in the next 100 years at most!

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Savaş Ateş

I'm a software engineer. I love Istanbul. I have been to 10 different countries. Istanbul is in the top 3 cities. I like to play soccer too :)

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