THE OBSERVED SITE EFFECTS AT THE STATIONS INFLUENCED BY 6^TH FEBRUARY 2023 TURKIYE EARTHQUAKES

This paper provides an initial evaluation of site effects observed at the selected stations influenced by the 6^th February, 2023 Kahramanmaras/Türkiye earthquakes. This assessment is conducted by the development of preliminary standard spectral ratio (SSR)-based site amplification relationship to suggest site factors at 0.2 sec (F_S) and at 1.0 sec (F₁) using a strong ground motion database including earthquakes with magnitude (M) ≥ 5.0 and epicentral distance (R_epi) < 300.0 km. The proposed amplification model composed of V_S30-scaling linear amplification and 5% damped pseudo spectral acceleration (PSA) is demonstrated to produce larger F_S and F₁ values for soft site conditions (e.g., V_S30 = 250 m/s) relative to TEBC (2019). For stiffer site profiles (e.g., V_S30 ≥ 400 m/s), the newly proposed model is found to provide F_S and F₁ values either similar to or less than those recommended in TEBC (2019). Despite the limitations of the proposed model, it might be regarded as an option to be adopted in seismic hazard computations for the regions affected by latest Türkiye events.