“The expected Istanbul earthquake may occur until 2026”

Stating that the North Anatolian Fault has 2 unbroken segments and that this situation threatens the Marmara and Eastern Anatolia Regions, Neotectonics and Earthquake Specialist Prof. Dr. Haluk Selim said that the expected Istanbul earthquake could occur until 2026. Selim also emphasized the importance of urban transformation projects by saying that the buildings on the Anatolian side of Istanbul carry a risk of 40% and the buildings on the European side have a risk of 60%.

On the 22nd anniversary of the 17 August earthquake, Dean of Engineering and Architecture Faculty in Istanbul Gelisim University, Neotectonics and Earthquake Specialist Prof. Dr. Haluk Selim said that there are 2 unbroken segments of the North Anatolian Fault and this carries a great risk. Noting that the ​​Marmara Sea and the Eastern Anatolia Region are under threat in this situation, Selim stated that "The North Anatolian Fault affected the region with two earthquakes that occurred in 1999. The North Anatolian Fault, which started in 1939, had a great impact in this geography, where we live, with approximately 11 earthquakes greater than 7.0 intensity in 60 years. The fault reached as far west as the 1999 earthquakes. But what happened next? Although it should have moved further west, it returned to Düzce and the second earthquake occurred. Currently, it still poses risks in the Marmara Sea."

THE NORTH ANATOLIA FAULT’S INFRANGIBILITY IS RISKY

Stating that there are 2 unbroken segments of the North Anatolian Fault, Prof. Dr. Selim said, “One of them is the Yedisu Segment, which is 100 kilometers long at its easternmost point. This segment is located on the part of the North Anatolian Fault extending up to Karlova. It hasn't been broken yet, and it poses a great risk. It can break at any moment and cause a devastating and damaging earthquake greater than 7 intensity. Another is the 115-kilometer fault line in the Marmara Region, one of the most important locations of the North Anatolian Fault. It wasn't broken either. Unfortunately, this is a possible earthquake that will affect many regions starting from Tekirdağ, centered in Istanbul, extending to Izmit and covering some districts of Bursa and Balikesir. It is also very wrong to call this a possible Istanbul earthquake since there are residential areas and population, industry and financial centers in many areas in this region.”

POSSIBLE ISTANBUL EARTHQUAKE MAY OCCUR UNTIL 2026

“The absence of this earthquake is not a good omen for the North Anatolian Fault. Here, the Marmara Region comes to the fore as a major risk factor,” said Prof. Dr. Selim and continued his words as follows:
“An earthquake occurred in this region on August 17, 1999. It has been 22 years and still no earthquake has occurred on the North Anatolian Fault. There are also reasons for this. These reasons should also be discussed. Looking at these periods, statistical information can emerge. If you consider only the Eastern Marmara, an earthquake (1999 earthquake) occurs in the range of 948, 256 and 245 years. That's the period. If you consider the West Marmara, an earthquake occurs 950 years later in Istanbul-centered earthquakes. Then, 257 years later, there is an earthquake and there is no earthquake afterwards. If we sum up the 257 years and the 1766 earthquake here, when we consider this period a little broader, a picture emerges as if the fault will break until 2026. But this is purely statistical information.”

TENSION IN THE AEGEAN SEA CAN MOVE THE MİDİLLİ FAULT, THE SİSAM ISLAND FAULT AND THE SMALL MENDERES, GREAT MENDERES AND GEDIZ GRABEN SYSTEMS

Prof. Dr. Selim said, “Currently, the risky area is in the Western Anatolia Region, maybe just south of Lesbos Island, on the part of the Lesbos Fault, maybe on the part towards Athens located in the Western part of Samos Island, faults in the sea or the small land extension. It can move the Menderes, Büyük Menderes and Gediz graben systems. Because in 2020, many earthquakes greater than 5 were recorded in and around the Aegean Sea. This is due to the 6.4 magnitude Crete Island earthquake that occurred on May 2, 2020. Currently, the Aegean Sea is constantly stretching. This region, namely the Aegean Sea and the Aegean Region, is completely at risk. The stress in this region also affects the North Anatolian Fault and delays the earthquake here, in the Marmara Region. The more earthquakes greater than 6 in the Aegean Sea, the more likely Istanbul earthquake in the Marmara Sea will be delayed.

RISK RATE IN THE BUILDING STOCK IN THE EUROPEAN SIDE OF ISTANBUL IS 60 PERCENT

“The northern branch of the North Anatolian Fault extends through the ​​Marmara Sea in an approximately east-west direction. The 115-kilometer fault line divides the Sea of ​​Marmara into two parts. Therefore, the fault line to be broken is 115 kilometers long, has a right-lateral geometry and is approximately 11-12 kilometers deep. The character of the fault here also has the capacity and energy to produce an earthquake with a damaging and destructive character greater than 7. If we start from the Anatolian side, especially in the structures in Istanbul; It should be said that there is a risk of 40 percent in the building stock up to Tuzla, Kartal, Pendik, Kadıköy and Üsküdar. When we look at the structures on the European side, this risk ratio reaches up to 60 percent because this collar has a wider beach section. In the continuation of the line extending to Silivri, the building stock in this section, which passes to Tekirdağ and its coast, is located in a highly risky area. The risk of liquefaction in the ground and the characteristics of the structures come to the fore here. It is imperative that financial problems are resolved on both the Anatolian and European Sides, local governments, citizens and the state cooperate to produce solutions and urban transformation of these buildings is carried out.”