Experts from the German Earth Sciences Research Center (GFZ) concluded that an earthquake with a magnitude of 7.4 could occur in the Marmara Sea in their research that analyzed the tectonic structure of Turkey.
Seismology experts from the German Earth Sciences Research Center (GFZ) Dirk Becker with Marco Bohnoff, in their new research in which they examined the tectonic structure in Turkey, reached important findings regarding the possible Marmara earthquake.
Experts, who defined the Marmara fault line in the south of Istanbul as a “seismic gap” in their research, concluded that an earthquake of more than 7 magnitude is expected in this region. Noting that the history of earthquakes in Istanbul reveals that a severe earthquake occurs in this region every 250 years, experts stated that the last time there was an earthquake of 7.4 magnitude in 1766.
In the study, it was determined that the Main Marmara Fault on the North Anatolian Fault Line, which hosts the boundary between the Eurasian and Anatolian tectonic plates, has not “activated” for a long time and therefore an earthquake with a magnitude over 7 is “overdue”.
Using a new high-resolution seismicity catalog in their research, experts examined around 14 thousand earthquakes that occurred in the Marmara Region between 2006 and 2020. Dirk Becker, the main author of the study, stated, “It is quite remarkable that almost all repetitive sequences occur in the western part of the Marmara fault. Only three sequences were detected in the middle-eastern region, while none were detected in the south of Istanbul.” Becker noted that the data analysis showed that “creep processes” occurring on the western fault line stabilized most of the tectonic energy, but that this creep margin gradually decreased towards the east. “Almost all of the Marmara fault in that region is locked,” Becker said.
Earthquake scenarios for Istanbul: Adalar or Ganos fault
Noting that the next earthquake in the region will probably occur in a region where the fault is “fully locked”, experts said that the earthquake will occur in the Adalar fault segment of the North Anatolian Fault Line south of Istanbul. However, the researchers noted that energy also accumulates on the locked Ganos fault in the west of the Marmara Sea, and drew attention to the fact that the last earthquake occurred here in 1912. Experts warned that if the Ganos fault breaks, the magnitude of the earthquake may exceed 7.4.
One of the authors of the study, Marco Bohnhoff, said, “The systematic transitions between the locked and creeping segments in this region are unique in the world. Therefore, it was only possible to illuminate them with a new process. The Istanbul earthquake scenarios mentioned in the study are of great importance in terms of risk estimation and measures to be taken for the protection of the people of the region.”