Microtremor tests and finite element numerical simulations were used to analyze the seismic ground motion effects of the Yunnan Dayao sedimentary basin. The results of the microtremor relative to the reference point spectral ratio (H-S/H-R) method showed that the spectral ratio curves of each observation point in Dayao basin show multipeak characteristics, indicating that the site consists of different soil layers; the predominant frequencies of each observation point mainly are 6 similar to 9 Hz in the basin and there are lots of differences in the predominant frequencies of different observation points, which indicate that the site stiffness of each observation point is different; the differences of spectral ratios between the east-west directions (EW) and the north-south directions (NS) reveal the site's anisotropy. The amplification coefficient characteristics of each observation point in the basin obtained by numerical simulation show that the predominant frequency is 6 similar to 9 Hz; the amplification coefficients of each observation point are different; the edge effect and the focusing effect amplify the seismic ground motion in the basin; the different amplification coefficients of the two sub-basins reflect the significant effect of the basin soil layers' differences on the seismic ground motion, the site is softer and amplification coefficients are larger; the slope degree of basin edges significantly affects the seismic ground motion near the basins edge, the amplification coefficients of the slope steeper and amplification coefficients larger. This study demonstrates that the microtremor test spectral ratio (H-S/H-R) method has good reliability applied to the analysis of basin effect and combining the finite element numerical simulation method is more effective in revealing the basin effect mechanism.

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 (Kg) 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 Kg 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 (Vs30) 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 Kg and lower Vs30 values, presents a higher risk of damage during an earthquake.