The 2023 Kahramanmaraş Earthquake Sequence and Regional Geology

The East Anatolian Fault Zone (EAFZ) forms a major tectonic boundary in southeastern Turkey, accommodating left-lateral strike-slip motion between the Arabian and Anatolian plates. This approximately 500-kilometer-long structure has produced repeated large earthquakes throughout recorded history, driven by the ongoing northward convergence of the Arabian plate at rates of 15–20 millimeters per year. The fault zone intersects with the North Anatolian Fault and the Dead Sea Fault, creating a complex triple-junction region prone to seismic activity. On 6 February 2023 at 10:24 local time, a magnitude 7.5 earthquake struck near Elbistan as part of the Kahramanmaraş earthquake sequence. The event originated at a depth of 7.4 kilometers. This shock followed an earlier magnitude 7.8 event near Pazarcık by several hours, with the two epicenters separated by 88 kilometers. Both earthquakes occurred on segments of the East Anatolian Fault, releasing accumulated strain along the plate boundary. The Kahramanmaraş region has experienced significant seismic events throughout its history due to its position on the EAFZ. Paleoseismic studies indicate recurrence intervals of several centuries for magnitude 7+ earthquakes on individual fault segments. The 2023 sequence ranks among the strongest since 2000, alongside the magnitude 7.5 Elbistan event and the magnitude 7.8 Pazarcık event, both occurring on 6 February 2023. Surface rupture associated with the sequence extended for tens of kilometers, producing measurable offsets consistent with the fault’s strike-slip character. Aftershock activity remained elevated for weeks, delineating the activated fault planes at shallow crustal depths. The region’s geology features a mix of metamorphic basement rocks, sedimentary basins, and volcanic deposits shaped by long-term tectonic deformation. Ongoing monitoring by regional seismic networks continues to refine understanding of stress transfer along the EAFZ. The 2023 events underscore the persistent seismic hazard in this tectonically active corridor.

References

USGS Earthquake Catalog Turkish Disaster and Emergency Management Authority (AFAD) reports