Microtremor analysis of local geological conditions

Abstract

The application of microtremor spectra in predicting frequency-dependent amplification effects of local site geology was investigated. Long time-interval (> 45 min) microtremor data were used to estimate Power Spectral Density (PSD) plots. Peaks occurring in these PSD plots were correlated with peaks of transfer functions (Haskell, 1960 and 1962) calculated from known geological models. The resulting apparent positive correlations indicate that a procedure of estimating PSD plots from long time intervals of microtremor data would be useful in predicting response spectra for earthquake risk evaluation.

Pemetaan Nilai Regangan Geser Tanah Untuk Kejadian-Kejadian Gempa Bumi Dengan Magnitude M ≥ 6.0 Sr Di Kota Jayapura

“…Gempa bumi merupakan fenomena alam yang bersifat merusak dan menimbulkan bencana. Ukuran sebuah gempa bumi adalah parameter yang sangat penting dan dapat dijelaskan dengan caracara yang berbeda [5]. Istilah yang sering dipakai untuk ukuran sebuah gempa bumi adalah intensitas gempa bumi, magnitude gempa bumi dan energi yang dilepaskan [5].…”

“…Ukuran sebuah gempa bumi adalah parameter yang sangat penting dan dapat dijelaskan dengan caracara yang berbeda [5]. Istilah yang sering dipakai untuk ukuran sebuah gempa bumi adalah intensitas gempa bumi, magnitude gempa bumi dan energi yang dilepaskan [5]. Dari ketiga ukuran gempa bumi, istilah yang paling terkenal di kalangan masyarakat umum adalah magnitude gempa bumi.…”

Site response on seismic motion in the Granada Basin (southern Spain) based on microtremor measurements

“…At sites with no significant local site response (bedrock), the ground velocity spectrum is approximately flat (white noise) over a wide frequency range, while at sites where the sediments and soils dominate the response, the spectrum of microtremors contains peaks that may provide information of the local site response. This feature has been used in microzonation studies (Kanai and Tanaka, 1961;Katz, 1976;Katz and Bellon, 1978;Ohta et al, 1978;Kobayashi et al, 1987a, b;Lermo et al, 1988;Seo et al, 1990;Morales et al, 1991b).…”

The Characteristics of Microtremors at the Site of SMART1 Array

“…• Many attempts have already been made to infer local geological conditions from microtremors. The rp.ethods include the use of predominate frequencies (Kanai and Tanaka, 1961) or power spectra (Katz, 1976) to determine shallow geological conditions. In both of these methods it is difficult to identify the source and propagation effects.…”