Mohammad R. Gliayamghamian - Engineering Seismology Department, International Institute of Earthquake Engineering and Seismology, P ۰, Box. ۱۹۳۹۵/۳۹۱۳, Tehran, Iran
Hideji Kawakami - Department of Civil and Environmental Engineering, Saitama University, Urawa, Saitama, Japan

A new method in microtremor spectral ratio analysis is introduced as a segmental cross-spectrum by the authors. The performance of segmental cross-spectrum in contrast with the conventional Fourier or power spectra is investigated through the analytical modeling and nu-merical simulations (Ghayarnghamain and Kawakami, ۱۹۹۷), Here, the objective of this paper is to examined the effects of segmental cross-spectrum and conventional methods in spectral ratio analysis of microtremor measurements. Results of microtremor data analysis is also indi-cate that the segmental cross-spectrum gives more reliable results for predominant resonance frequency and amplification factor of the soil system. Furthermore, results demonstrate that segmental cross-spectrum together with H/V technique can strongly compensate for the source effects in microtremor response of the sites. This is an important conclusion regarding the possibility of removing source from local site effects in microtremors