The following post is a report written after I interviewed and asked 7 different PhD holding geologists, some of who live in Iraq, UAE, and the United States of America. Everything in this post was reviewed by them ahead of posting.
One of the scenes that spread on social media recently was of footage from above, perhaps from an aeroplane or a drone, showing how entire neighbourhoods were flattened by the earthquake that occurred in northern Syria and southern Turkey at dawn on Monday, February 6, and puts itself on a list The strongest in nearly a century, according to the US Geological Survey, and we did not talk about a subsequent earthquake after nine hours that was almost the same intensity or a little less.
With a magnitude of 7.8 on the Richter scale, this major earthquake places itself in fifth place in the list of the most powerful earthquakes of the twenty-first century, a list topped by the Indian Ocean earthquake and tsunami in December 2004 also known as the "Boxing Day" tsunami, and its epicentre was off the west coast of North Sumatra in Indonesia, the earthquake measured 9.1-9.3 on the scale and caused tsunamis 30 meters high, like the length of a building with 10 stories!
You may be wondering about the secret of the strength of these earthquakes, and why certain countries, such as Turkey, specifically experience many of them. In fact, during the past ten years, Turkey witnessed only six earthquakes above the scale of 6 degrees, in addition to the earthquakes of February 6, as well as fifty earthquakes in the past century on the same scale, but to understand the matter, let us start by knowing what the earthquake means in the first place.
What originally caused the earthquake?
If we imagine that the planet Earth is like an apple, then the layer of the earth's crust is simply the thin crust of the apple, but this earth's crust has a thickness of 30 to 70 kilometres in the continents, and from 6 to 12 kilometres in the oceans, and it differs in something else from the apple's crust, which is that it is not a single piece that covers the earth, but rather consists of a number of pieces called tectonic plates, which overlap with each other in a way that resembles paper puzzles. Therefore, we do not notice its effect.
These tectonic plates are moving away from each other in places and approaching in others, and as the sides of two tectonic plates approach each other in one place, they rub against each other to create what scientists call the “fault”. The nature of the fault’s friction differs according to the nature of the rocks that rub against each other and the direction of movement, the two sides of the cloud may slide in opposite directions, but at the same level, or one of them may move up or down.
In the normal case, the edges of the plates slide slowly and smoothly, but sometimes it is not like this. To understand this idea, imagine that there are two large pieces of marble with an area of several square meters, each of which has a non-smooth face. We tied the top of them with a strong rope and began to pull them. At first, the piece does not move, so we increase the tensile strength, and with tension, the marble piece suddenly slips and moves for several centimetres, and during its movement, you notice that it vibrates severely.
Why is Turkey considered a critical region in terms of earthquakes?
This is exactly what happens in the case of an earthquake, but instead of the vertical position, the rocks of the ends of the two plates meet horizontally.
Sometimes they rub against each other so they stand for a while, while each of them stores energy in this friction (this is the case in which you try to stretch but the piece of marble doesn't move yet), and at some point that energy escapes and those rocks shift to an unusually large distance, and with their displacement, the energy spreads everywhere in the planet, but it hits the closest points to it with the greatest force.
Turkey, in particular, faces a problem with this matter, as it is located on a small tectonic plate called the Anatolian plate, which pushes to the west due to the movement of two large neighbouring plates, the first is the Eurasian plate from the east and north, and the second is the Arabian plate in the south, and in addition to this is the influence of the movement of the African plate, intertwining these moves put Turkey in a seismically critical area.
The continuous frictions between these tectonic plates caused the construction of two large faults in Turkey.
The first is the North Anatolian fault, which runs at a distance of 1,500 km and its main line is only 20 kilometres away from Istanbul. The second is the East Anatolian fault, with a length of 700 km. The last earthquake occurred due to a breakdown of energy. It occurred between the two sides of the East Anatolian fault, and the country has suffered from large earthquakes exceeding seven degrees due to both during the past hundreds of years, and unfortunately, it will suffer from similar earthquakes in the future.
How did Turkey's earthquake spread to a distance of a thousand kilometres outside the country?
At this point, if you're still reading, you must be wondering about the spread of the earthquake, how can a force inside move to a wide circle that exceeds a thousand kilometres outside Turkey, where the earthquake was felt by some citizens in Egypt?
At this point we need to differentiate between the size or measurement of the earthquake (Magnitude) and its strength (Intensity), the first measures the earthquake wave itself and the second measure its effect on you. To understand the matter, imagine that an earthquake - whatever it is - is a light bulb that has a specific scale, some lamps, for example, have a capacity of 25 watts, and some have a capacity of 100 watts, and so on.
Now put each of the two lamps in a large room. Of course, you will notice that exactly below the lamp the illumination is higher, but as you move away from the centre of the lamp the illumination dims, and after some distance, for example, twenty meters, the effect of the lamp light is very weak, but what is certain is that the lamp is of a scale of 100. Watts, The light from it will cover more area than a 25-watt lamp.
The same is true in the case of earthquakes.
The scale of an earthquake here is like the scale of a lamp, which measures earthquake waves emanating from the interior of the earth, but unlike the lamp is a scale that rises logarithmically, this means that each degree on the earthquake scale is ten times larger than the one that precedes it, so the earthquake has a scale of 7.0 degrees. It is ten times larger than the 6.0-magnitude earthquake, and this is an important point.
If you reflect on it a little, you will understand the secret of the difference between major earthquakes such as this earthquake, and smaller ones in general. The largest earthquake on the scale is not only stronger, but it spreads to a wider distance, just as the light of a lamp worth 100W is more powerful, and it spreads to a wider distance.
Why are larger earthquakes (on the scale) more destructive?
Let's compare, for example, the earthquake that struck Egypt in 1992 and caused the death of hundreds of people. It was on a scale of 5.8 degrees, with the first earthquake in Syria and Turkey on a scale of 7.8 degrees. This means a difference of two degrees in the scale, each degree of which means ten times more. The earthquake in Syria and Turkey was 100 times greater because, in the case of logarithmic escalation, we multiply and not add. But this is the scale or magnitude, so what about the strength of the earthquake itself?
The strength or intensity expresses how you feel about the earthquake, the amount of vibration that you get, whatever your house shape and size is, and like the case of the lamp, the strength of the earthquake varies from one place to another depending on how far away you are or how close you are to the centre of its occurrence, so the closer you are to the centre of the earthquake wave, the more you feel this force in a way bigger, and of course the larger the magnitude of the earthquake, the stronger you feel it.
The main difference here is that while the difference between a degree and a degree on an earthquake scale is 10 times the magnitude of an earthquake, on the other hand, it is equivalent to 32 times its magnitude. This means the following: a 7.0-magnitude earthquake would be 32 times stronger (in its impact) than a 6.0-magnitude earthquake.
If we go back to the previous comparison, the earthquake in Turkey and Syria will be almost 1000 times stronger compared to the earthquake in Egypt. In fact, a magnitude 7 earthquake releases energy equivalent to 30 nuclear bombs like those dropped on the Japanese city of Hiroshima in 1945, while an 8-magnitude earthquake releases energy equal to the detonation of 1,000 nuclear bombs of the same type. The nonlinearity principle that earthquakes follow is a difficult concept to understand.
Have you ever heard of the famous legend that says: “The king of India admired the intelligence of one of his ministers, so he asked him to wish what he wanted?” The legend says that the minister asked that one grain of rice be placed in the first square on the chessboard, and then successively the resulting number is doubled from square to square.
The king did not understand the intent and thought it a trivial request, but the non-linear escalation was similar to the previous case. After very short squares, the king realized that he would have to give the minister all his kingdom, and it will not be enough for him!
You can try this idea yourself, just multiply 2X2 on the calculator on your smartphone, then keep pressing the "equals" button. You may be surprised that after only about thirty clicks you have passed the first billion, but it takes fewer clicks by a clear difference to cross a trillion! This is, roughly speaking, what happens in rising seismic scales, and now you know what a 7.8-magnitude earthquake means.
What does it mean that the epicentre of the earthquake was at a depth of 18 kilometres?
The matter does not stop at this point. I said a while ago that the energy released from the first earthquake in Turkey and Syria was equal to hundreds of nuclear bombs. This does not mean that the matter is similar to throwing hundreds of nuclear bombs on the cities of Gaziantep or Kahramanmaraş, but it means that the energy released from the earthquake specifically in its focus inside the Earth's interior, is equal to hundreds of nuclear bombs.
This energy travels in the form of waves to be distributed everywhere on the planet, and the largest place that receives the blow remains the one that is located exactly above the focus, and it is called the "surface centre" (Epicenter), In the case of the first Turkish-Syrian earthquake, the surface centre was near Gaziantep, and in the case of the second earthquake, the surface centre was near its neighbour, Kahramanmaraş.
Unfortunately, the epicentre of the Turkey earthquake was relatively close to the surface (about 18 kilometres), which caused greater force to be pushed into the surrounding area (the cities of Gaziantep and Kahramanmaraş), which added to the strength of the tremor in the region and dropped a large number of Houses on the ground.
Besides, the strength of the earthquake is also affected by the nature of the ground itself and the nature of the buildings. Buildings that are old or not structurally equipped to deal with earthquakes will be the first to fall, even with earthquakes weaker than this.
The earthquake strongly struck several areas along the fault line, bringing down houses over the heads of the victims in many areas in Turkey, such as Malta, Kahramanmaraş, Gaziantep, Diyarbakir, Urfa, Adana, and in Syria, Jarabulus, Aleppo, and the impact reached Damascus and Beirut, with less damage by a clear difference, but people left anyway from their homes and spent the night in the streets.
In conclusion
All the previous factors came together to cause the disaster, and unfortunately, the number of deaths will not stop at this point, many bodies are still expected to be exhumed, not the living. Generally, most survivors are extracted from the wreckage within the first 24-48 hours of the crash, after which day by day the odds drop drastically.
Medically, a person can stay on average about 5-7 days under the wreckage, but by that time the odds are usually very weak, and this limit is what the United Nations sets to find survivors and end search and rescue operations, but there remains hope that some will cross this limit.
This has happened before, after the Haiti earthquake in January 2010, a man survived for 12 days under the rubble of a fallen shop. Later, another man was found alive 27 days after the earthquake, but these remain exceptional cases, and what is certain is that with the passage of time, the chances of finding survivors diminish, and the probability of finding more victims and bodies increases.