A fault unzipping toward a megacity
One fault has been failing westward, quake by quake, toward Istanbul.
The North Anatolian Fault has ruptured in a remarkable sequence over the last century, each earthquake loading the next segment to the west. That progression points at the Sea of Marmara, right beside Istanbul and its millions of people.
What is happening at Marmara Sea
The North Anatolian Fault is a transform fault, much like the San Andreas, where the Anatolian Plate slides west past Eurasia. It runs across northern Turkey and out under the Sea of Marmara.
Since 1939 it has produced a striking domino line of large earthquakes marching from east to west. The section beneath the Marmara Sea, just south of Istanbul, is the conspicuous gap that has not yet released.
The hazard record here
THE RECORD HERE
A magnitude 7.6 earthquake struck here in 1999.
Epicentre: 4 km ESE of Derince, Turkey.
Live figures from the QuakeMate hazard API - USGS earthquake catalog, NOAA tsunami database and published recurrence estimates. Some fields are blank where there is no record.
Recent earthquakes at Marmara Sea
- 1.2WESTERN TURKEY2 weeks ago · 16/07/2026, 06:11:51 · 13 km deep
- 1.5WESTERN TURKEY5 days ago · 27/07/2026, 06:11:00 · 10 km deep
- 3.2WESTERN TURKEY3 weeks ago · 10/07/2026, 00:59:05 · 7 km deep
- 1.9WESTERN TURKEY4 days ago · 27/07/2026, 17:02:01 · 8 km deep
- 1.3WESTERN TURKEY4 weeks ago · 02/07/2026, 19:55:38 · 7 km deep
- 1.6WESTERN TURKEY3 weeks ago · 06/07/2026, 04:00:01 · 10 km deep
94 more earthquakes at Marmara Sea
Open the QuakeMate app to see every quake here, sorted and mapped - plus real-time alerts when a new one strikes.
Notable events
1939
The M7.8 Erzincan quake began the westward sequence.
1999
The M7.6 Izmit earthquake struck just east of the Marmara gap.
2023
Turkey’s catastrophic quakes on a different fault renewed focus on Istanbul’s risk.
What scientists watch
Turkish and international teams monitor the submerged Marmara segment with seafloor sensors, watching for the strain that has built there.
Staying ahead of it
A Marmara rupture would sit on the doorstep of a megacity - the earliest alert reaches the most people in the fewest seconds.
Get QuakeMate freeGet warned before the next one at Marmara Sea.
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Marmara Sea: common questions
Why is Istanbul considered at high earthquake risk?
The North Anatolian Fault has ruptured segment by segment from east to west, and the section under the Sea of Marmara next to Istanbul has not released in a long time, so it is widely regarded as loaded for a large quake.
Is the North Anatolian Fault like the San Andreas?
Yes, both are major transform faults where plates slide sideways past each other and both produce large, damaging earthquakes. The North Anatolian is known for its clear west-migrating sequence.
Related hazard zones
Earthquake data via the QuakeMate API (USGS, EMSC and regional agencies). Historical notes summarise well-established events; magnitudes and dates follow the published record. Live figures may be revised.