Fundamental Site Frequency Based on H/V Spectral Ratios of Iranian Earthquakes Using Strong Motion Data

Document Type : Original Article


1 Faculty member-Iran Strong Motion Network-Road, Housing & Urban Development Research Center

2 Iran Strong Motion Network, BHRC

3 ISMN, Road, Housing and Urban Development Research Center, Tehran, Iran

4 ISMN. Road, Housing and Urban Development Research Center, Tehran, Iran


In this study, horizontal-to-vertical (H/V) spectral ratio have been calculated for strong ground motion data recorded by the Iranian Strong Motion Network (ISMN). Then, a uniform and specific procedure is applied for selecting the peak frequency (fpeak) of the average H/V spectral ratio for each station in the database. Based on this procedure, the fpeak value is estimated at 467 stations of ISMN. Also, the relationship between peak frequency and time-averaged shear-wave velocity in the upper 30 m (VS30) has been investigated and this relationship is presented for Iran. The results and uncertainties of the model are compared with other related studies conducted in Japan, Central and Eastern North America (CENA), as well as previous studies for Iran. Compared to other datasets, the VS30 model presented for Iran shows the highest VS30 values ​​among all models. The equation developed in this study can be used to estimate VS30 at ISMN stations where there is no other site characteristics. Also, using the peak frequency obtained, the soil type can be classified according to the 2800 standard.


Main Subjects