High-Resolution Coseismic Surface Displacement Measurements Between Çiğli and Hassa along the surface rupture of 6 February 2023, Kahramanmaraş Earthquake (Mw 7.8),Türkiye

This study examines the first event of the doublet earthquakes (Mw 7.7 and Mw 7.6) that
impacted Türkiye on February 6, 2023. Following the earthquake, data related to surface
rupture and slip distribution were obtained using satellite-based geodetic and remote
sensing methods. While these studies are important for understanding bulk deformation;
detailed field investigations that map and measure coseismic deformation, illustrate fault
geometry, sections and jog relationships and calculate displacements from deformed
objects remain insufficient. To fill this gap, high-resolution ( <10 cm) UAV imagery was
utilized by Istanbul Technical University Earth Bee Lab to produce a continuous 300-meters-
wide strip map along the full extent of the surface rupture.
Our fault map was created based on these imagery datasets and identified a rupture length
of approximately 80 km, extending between Çiğli and Hassa. The rupture is divided into five
primary sections: İslahiye, Beyoğlu, Türkoğlu, Küpelikız and Kapıçam. Deformation zone
widths vary significantly, ranging from a few meters to 700m, with narrow, concentrated
zones in Kapıçam, Türkoğlu and Beyoğlu Sections compared to İslahiye and Küpelikız
Sections. The widest deformation zones were observed at the jogs along section
boundaries.
Displacements were categorized as ‘’On Fault’’ for those occurring along the main fault line
and ‘’Off Fault’’ more than 10 meters away from the main rupture. The aim was to reveal the slip
partitioning along the fault. Analysis of 1419 coseismic displacement measurements ( 1233
On Fault and 186 Off Fault) reveals maximum slips of 8.56 ± 0.8 m in the Beyoğlu Section
and 7.9 ± 0.3 m in Kapıçam Section with an average slip of 2.19 m. These values are higher
than the previously provided maximum displacement value of 7.3±0.2 m measured in the
Büyüknacar Area.The highest concentration and magnitude of displacements were observed
in the Beyoğlu Section and at the Beyoğlu-Küpelikız transition along the surface rupture
between Çiğli and Hassa.