Full-scale measurements have been conducted for a 270-m tall building in Hong Kong. Acceleration response data of the tall building has been collected during Typhoon Kammuri and 512 Wenchuanearthquake in 2008. Based on two sets of acceleration data, dynamic modal properties of the tall building were identified by two methods. One is the traditional method of empirical mode decomposition (EMD) combined with the Random decrement Technique (RDT), the other is the recently proposed Fast Bayesian method using the fast Fourier transform (FFT). The natural frequency of each mode identified by these two different methods is very close to each other. Noticeable differences are observed for damping ratio results associated with each mode. The identified results can also be compared between two excitation events. As expected, wind-induced acceleration data suggests almost the same frequency values compared to the results identified from the acceleration data due to the long-distance earthquake. However, the damping ratios corresponding to Wenchuan earthquake were found to be larger than the damping results of the tall building under typhoon excitation. The difference of two sets of damping ratio results might be attributed to the the role of aerodynamic damping, which could be estimated from the two sets of damping ratio.