Statement from Şener Üşümezsoy regarding the earthquakes off the coast of Büyükada: Is it a harbinger of a larger earthquake?

The 2.2 and 3.0 magnitude micro-earthquakes that occurred off the coast of Büyükada, Istanbul, on August 19, 2026, have brought the discussions regarding the fault lines in the Marmara Sea back to the agenda. Geologist Prof. Dr. Şener Üşümezsoy stated that the tremors should not be interpreted as a harbinger of the expected major Istanbul earthquake.

Making assessments following the activity that occurred two days after the 27th anniversary of the August 17, 1999 earthquake, Üşümezsoy stated that there is no unusual situation on the main fault. Üşümezsoy said, "The Adalar fault is an old and dead fault. A major earthquake will not originate from here."

TREMORS ARE ON SECONDARY FAULTS

According to Üşümezsoy, the small-scale earthquakes recorded south of Büyükada did not occur directly on the Adalar fault, but on secondary and tertiary fault branches that cut the main fault from south to north. Emphasizing that these branches do not have the capacity to accumulate stress on a scale that would produce a destructive earthquake, Üşümezsoy evaluated the activity as a small-scale release of stress transfer that had previously occurred in the region.

Prof. Dr. Üşümezsoy also said that these micro-tremors are consistent with the fault maps they drew years ago. Stating that similar triggered small events have been experienced in the region since 1999, Üşümezsoy expressed that the recent earthquakes should be seen as part of a normal process.

The expert noted that the perception in the public that "the Istanbul earthquake is coming" does not reflect the truth, and that such micro-earthquakes around the Adalar do not, by themselves, create an expectation of a medium or high-intensity earthquake.