Clustered Microearthquake Swarm Recorded South of Istanbul's Princes' Islands
Between August 18 and August 20, 2026, Boğaziçi University’s Kandilli Observatory and Earthquake Research Institute (KRDAE) along with the Disaster and Emergency Management Presidency (AFAD) registered a microearthquake swarm in the Sea of Marmara. Kandilli identified 117 seismic events ranging from magnitude 0.7 to 3.1 within a 20-kilometer radius south of the Princes' Islands. Concurrently, AFAD documented over 30 tremors in a 24-hour window, with the peak event measuring magnitude 3.2 at focal depths ranging between 7 and 17 kilometers.
According to seismological assessments, the recorded events exhibited normal-component oblique strike-slip mechanisms consistent with the active geometry of the North Anatolian Fault system under the Sea of Marmara. Geologists have noted that microearthquake clusters are typical in active tectonic settings, and 24/7 monitoring continues via regional observation centers.
Sources:
Turkish Minute: Turkish observatory records 117 microearthquakes south of İstanbul in 55 hours
Türkiye Today: Kandilli records 117 earthquakes south of Istanbul's Princes' Islands in 2 days
Türkiye Today: Quake swarm shakes Istanbul with over 30 tremors in 24 hours
