The 2023 Kahramanmaraş Earthquake Sequence: Geological Setting and Historical Context

On 6 February 2023 at 01:17 local time, a magnitude 7.8 earthquake struck near Pazarcık in Kahramanmaraş Province, southeastern Turkey. The event occurred at a focal depth of 10 km and formed the initial and largest shock in a destructive sequence. Later the same day, a magnitude 7.5 earthquake occurred near Elbistan, approximately 88 km northeast of the Pazarcık epicenter. Both events are officially designated as the Kahramanmaraş earthquake sequence.

The region lies within a tectonically active zone at the junction of the Arabian, African, and Anatolian plates. The East Anatolian Fault Zone (EAFZ), a major left-lateral strike-slip system, accommodates the westward extrusion of the Anatolian plate. The Pazarcık rupture propagated along a segment of the EAFZ, while the subsequent Elbistan event activated a separate but connected fault strand. The shallow focal depth amplified ground shaking across a broad area.

Southeastern Turkey has experienced repeated large earthquakes throughout recorded history due to its position on the EAFZ. Notable prior events include the 1822 Aleppo earthquake and the 1893 Malatya earthquake, both of which produced extensive surface rupture along the same fault system. Instrumental records since 2000 document elevated but lower-magnitude seismicity along the EAFZ prior to 2023, consistent with the fault’s long-term slip rate of approximately 6–10 mm per year.

The 2023 sequence released strain accumulated over centuries. Post-event analyses indicate bilateral rupture propagation during the magnitude 7.8 event, with surface offsets exceeding 3 m in places. The close timing and proximity of the magnitude 7.5 Elbistan shock illustrate the ability of one large earthquake to trigger failure on adjacent fault segments within the same tectonic corridor.

Ongoing monitoring by national and international networks continues to record aftershocks distributed along the EAFZ. These data contribute to refined seismic hazard models for the region, emphasizing the need for updated building codes and preparedness measures in proximity to the East Anatolian Fault.

References

USGS Earthquake Catalog (event parameters and sequence details)
Tectonic framework from peer-reviewed studies on the East Anatolian Fault Zone (slip rates and historical ruptures)