Analysis of horizontal to vertical spectra of microseisms for Baku city

The 25 th November 2000 earthquake raised public awareness about earthquake catastrophe. Although the city did not witness the heavy damages and life losses, however the event traced slight to moderate damage in Baku city. The distribution of damage is caused by local site effect. In this study, aiming to estimate local site effect, analysis of the ratio of horizontal to vertical spectra of microseisms on the basis of microtremor measurements was performed. The measurements are conducted with the Guralp CMG-5TD accelerometer with the Nakamura's approach. Dynamic characteristics of surface ground (predominant frequency F, amplification factor A) are estimated. The maps showing the distribution of the amplification and resonance frequency for the grounds of Baku city were developed which demonstrate variability and heterogeneity of ground characteristics in the city. The results can be applied for urban seismic hazard assessment researches in the future.