Single-station microtremor surveys for site characterization: A case study in Erzurum city, eastern Turkey

Abstract

The single-station microtremor method is one of the fastest, most reliable, and cheapest methods used to identify dynamic soil properties. This study utilizes 49 single-station microtremor measurements to identify the dynamic soil properties of the Hilalkent quarter of the Yakutiye district in Erzurum. Soil dominant frequency and the amplification factor were calculated by using the Nakamura horizontal/vertical spectral ratio (H/V) method. While the soil dominant frequency values varied between 0.4 Hz and 10 Hz, the soil amplification factor changed between 1 and 10. Higher H/V values were acquired with lower frequency values. The vulnerability index (K_g) and shear strain parameters that are utilized to estimate the damage that may be caused by an earthquake were mapped. Especially in the west side of the study area, higher K_g values were observed. The shear strain map was created with 0.25 g, 0.50 g and 0.75 g bedrock accelerations, and soil types that lost elasticity during an earthquake were identified. The average shear wave velocity for the first 30 m (V_s30) was calculated. Finally, it was observed that the western part of the study area, which resulted in a higher period and higher H/V, higher K_g and lower V_s30 values, presents a higher risk of damage during an earthquake.