Seismic Swarm S20230206.2: Analysis of Activity Near Göksun, Turkey

Seismic swarm S20230206.2 was recorded in the vicinity of Göksun, Turkey, beginning at 10:47 on 6 February 2023 and concluding at 16:50 on 20 February 2023. Over 342 hours and 3 minutes, the sequence produced 332 earthquakes. The epicentral area lies approximately 9 km north-northeast of Göksun in Kahramanmaraş Province, within a tectonically active corridor of the Eastern Anatolian Fault Zone.

This region experiences frequent seismicity due to the convergence of the Arabian and Anatolian plates. The Eastern Anatolian Fault accommodates left-lateral strike-slip motion at rates of 6–10 mm per year, forming part of the broader boundary that separates the Arabian plate from the Anatolian microplate. Shallow crustal earthquakes predominate, with focal depths commonly between 5 and 15 km. The February 2023 sequence occurred amid elevated regional stress following the Mw 7.8 and Mw 7.6 mainshocks of 6 February, though the swarm parameters are treated here as an internally classified SeismoSight event.

Examination of the first 100 recorded events reveals a rapid onset of activity on 6 February, with magnitudes ranging from 2.5 to 6.0 and depths predominantly between 5 and 15 km. The largest event, magnitude 6.0, occurred at 12:02 on 6 February at a depth of 8 km. Subsequent events clustered in the afternoon and evening hours of the same day, including multiple magnitude 4.7–4.8 shocks at depths of 9–11 km. Depths showed modest variation, with occasional deeper readings up to 27 km early in the sequence and shallower foci near 1–5 km later on 6 and 7 February. Magnitudes declined gradually after the initial peak, with most events falling between 2.5 and 4.4 by 8 February. The temporal distribution indicates intense early productivity followed by a steady decay over subsequent days.

Historical records maintained since 1 January 2000 document only one prior swarm in the immediate area, confirming the exceptional nature of the 2023 sequence within the local catalog. No comparable swarm activity appears in the preceding two decades.

The swarm underscores the persistent seismic hazard along the Eastern Anatolian Fault. Continued monitoring remains essential for understanding stress redistribution and aftershock patterns in this densely populated region of southeastern Turkey.

References

SeismoSight internal swarm classification S20230206.2
USGS Earthquake Catalog (regional tectonics)
Directorate of Mineral Research and Exploration (MTA), Turkey – Active Fault Map of Turkey (updated 2023)