New Study Maps Earthquake-Prone Fault Structure Beneath the Sea of Marmara

A new scientific study has produced the most detailed three-dimensional image to date of the fault structure beneath the Sea of Marmara, offering fresh insight into the seismic risk facing Istanbul and surrounding regions.

The research was conducted by an international team led by scientists from Science Tokyo, in collaboration with researchers from Boğaziçi University. The findings were published in the peer-reviewed journal Geology.

Using three-dimensional electromagnetic imaging, the team mapped variations in the electrical properties of rocks along the North Anatolian Fault beneath the Sea of Marmara. According to the researchers, zones with higher electrical conductivity are likely linked to fluid-rich areas, which can weaken fault strength and influence how ruptures initiate.

The study focuses on a section of the fault that has remained seismically quiet for more than two centuries. Researchers note that this segment sits between areas that have ruptured in past major earthquakes, increasing interest in how stress may be accumulating beneath the Marmara Sea.

In addition to identifying potential locked sections of the fault, the imaging also reveals contrasts between mechanically stronger and weaker zones. Scientists say this distinction could help refine models of rupture propagation, improving estimates of how an earthquake might spread once it begins.

The Sea of Marmara lies directly south of Istanbul, a metropolitan area home to more than 15 million people. Experts have long warned that a major earthquake along this section of the North Anatolian Fault would have serious consequences for the city and the wider region.