The 2023 Pazarcık (Kahramanmaraş, Türkiye) earthquake (M _w 7.7): implications for surface rupture dynamics along the East Anatolian Fault Zone

Abstract

Southern Türkiye faced widespread catastrophic destruction by two devastating earthquakes on the same day. As the earthquakes occurred at 04:17 (Mw=7.7, Pazarcık, Kahramanmaraş) and 12:30 (Mw=7.6, Elbistan, Kahramanmaraş) on February 6, 2023, neighboring active fault systems were broken in succession between the Hatay and Malatya Provinces in the region. The first earthquake, one of the largest earthquakes in this region during the last century, caused widespread damage to infrastructure and buildings, and produced large scale seismo-gravitational surface deformation such as landslides, lateral spreading, liquefaction and also extensional cracks. Here, we present the surface rupture geometry and coseismic displacement characteristics of the fault systems, determined with field observations immediately after the February 6, 2023 Pazarcık (Kahramanmaraş, Türkiye) earthquake (Mw=7.7). Preliminary results show that the total rupture length (L max ) is 270±10 km on the Karasu, Pazarcık and Erkenek segments of the East Anatolia Fault Zone. Left-lateral strike-slip faulting is developed with a maximum horizontal displacement (D max ) of 7.30 m and an average displacement (D avg ) of 3.00 m. Although the surface rupture generally exhibits a narrow deformation zone width of 2-5 m, it expands up to 50 m in some sections of the faults. Our implications for rupture dynamics suggest that fracture development started on a secondary fault (Narlı Fault), transferred to the main fault and triggered the breaking of asperities on Pazarcık segment which exhibits a long period accumulation of stress to initiate the major rupturing. Supplementary material: Figures S1 – S12 with details on coseismic displacement are available at: https://doi.org/10.6084/m9.figshare.c.6487245

The complex dynamics of the 2023 Kahramanmaraş, Turkey,Mw7.8-7.7 earthquake doublet

“…1B). Slip at the surface is highly heterogeneous, which is consistent with field observations ( 18 ), but on average increases from the southwest to the northeast ends of the M w 7.8 rupture (fig. S8).…”

Surface deformations of the 6 February 2023 earthquake sequence, eastern Türkiye

“…The thin line connecting (C) and (D) points to the same blue data point. (E) Displacements along the EAFZ (excluding Narlı) plotted versus distance (+ is to northeast, – is to southwest) from fault intersection zone (table S1) ( 59 ). (F) Displacements from Sentinel-1 satellite data plotted along the length of the EAFZ ( 9 ).…”

High-resolution co-seismic fault offsets of the 2023 Türkiye earthquake ruptures using satellite imagery

“…The Mw 7.8 rupture initiated on the Narli fault, 15 km south of the main strand of the EAF (Fig. 3a) and later propagated bilaterally along the main strand of the EAF along the Erkenek segment towards the northeast and along the Pazarcik and Karasu/Amanos segments towards the southwest [6][7][8][9][10][11] . The second earthquake initiated on the Çardak fault (Fig.…”

“…3a). The 2023 doublet is the strongest earthquake documented on the EAFZ since 1114 CE 6,10 and represents a unique opportunity to map the active faults in the region. Indeed, several studies have suggested various segmentation models of the EAF that differ on the location of the active faults and active plate margins in this region 3,[12][13][14][15][16] .…”