Seismic Swarm Activity in Eastern Turkey: February 2023

Eastern Turkey lies at a complex tectonic junction where the Arabian Plate converges with the Eurasian and African plates. This setting produces frequent seismic events along major structures including the East Anatolian Fault Zone and the Bitlis-Zagros suture. The region experiences both strike-slip and thrust faulting, contributing to elevated earthquake hazard.

Between 02:03 on 6 February 2023 and 10:18 on 7 February 2023, a swarm comprising 14 earthquakes was recorded in Eastern Turkey. The sequence lasted 32 hours and 14 minutes. Event magnitudes ranged from 4.2 to 6.0, with focal depths between 5 km and 16 km. The largest event reached magnitude 6.0 at 10:26 on 6 February at a depth of 10 km. Other notable shocks included a magnitude 5.8 at 10:35 and a magnitude 5.7 at 10:51, both at 10 km depth.

The temporal distribution showed clustering within the first 12 hours, followed by a gradual decline. Depths remained predominantly shallow, consistent with activity on upper-crustal faults typical of the East Anatolian system. Such swarms often reflect fluid migration or stress transfer along segmented fault strands rather than a single mainshock-aftershock sequence.

Historical records since 2000 indicate ten prior swarms in the same region. These occurred in 2007 (three swarms), 2010 (one), 2015 (one), 2017 (one), 2019 (one), 2020 (two), and 2023 (one). The 2023 swarm fits within this pattern of episodic clustered seismicity.

Geological monitoring in Eastern Turkey relies on regional seismic networks that provide rapid detection of events above magnitude 4.0. Depths in the 5–16 km range align with the brittle-ductile transition zone in continental crust of this area. Continued observation supports improved understanding of strain accumulation along the plate boundary.

References

SeismoSight internal swarm classification PS20230206.2
USGS Earthquake Catalog (Eastern Turkey tectonics)
EMSC Regional Seismicity Reports (2023)