Overview of Historic Masonry Building Performance During the February 6^th, 2023 Kahramanmaras, Turkey Earthquake Doublet (M_w 7.8 and M_w 7.6)

On February 6^th, 2023, two devastating earthquakes (M_w 7.8 at Pazarcik and M_w 7.6 at Elbistan/Ekinozu) struck multiple cities in the south-east of Turkey, causing extensive damage and collapses in both reinforced concrete and masonry (mostly historic) structures. This paper presents findings from a reconnaissance study in the heavily impacted cities of Kahramanmaras, Adiyaman, and Hatay (Antioch) in Turkey. As these cities house historic/antique structures such as mosques, churches, mansions, etc., this study specifically focuses on historic masonry buildings that suffered severe structural damage or collapsed entirely during these earthquakes. The primary objective is to categorize the typical damage patterns observed. Key factors influencing seismic performance include structural regularity, mass and stiffness distribution, construction material quality, floor flexibility, and the proportion of wall openings (limited to 19% of wall length as per the Turkey Building Earthquake Code 2018). This reconnaissance reveals that the causes of damage are primarily attributed to proximity to the epicenter (i.e., very high ground accelerations), poor soil conditions (liquefaction, soil amplification), low-quality mortar used, inadequate masonry unit strength, and various irregularities within the structural system. Furthermore, inappropriate interventions by the users exacerbated the damage, leading to severe destruction or even collapse, resulting in numerous casualties. Minaret damage and collapses constitute various examples of masonry behavior and are discussed as well. Finally, some examples of retrofitting techniques that could be implemented to rehabilitate Turkey’s historical masonry building stock for future earthquakes are presented.