Abstract
H/V spectral ratios from microtremors areused to retrieve the S-velocity structurefrom a single ambient vibration record, byusing its relation to the ellipticity ofthe fundamental mode Rayleigh wave and theamplitude of observed H/V ratio.Constraints are needed in order to restrictthe possible range of solutions, and theinversion is applied to sites where thethickness of the unconsolidated sedimentsis approximately known from boreholeinformation. Within the uncertainty, theinverted structures agree well with theresults from other S-wave measuringtechniques such as downhole and cross-holemeasurements, and the analysis of ambientvibrations measured on an array.The influence of the inversion uncertaintyon site-amplification estimates forearthquakes is then investigated. For allinverted models, site response is computedfor a large number of events, which allowsto define the uncertainty by the aprioriunknown source position and mechanism of afuture earthquake. In most cases thevariability between the results obtainedfor the different models is much smallerthan the variability introduced by theunknown source position. The accuracy withwhich S-wave velocity structures can beretrieved from observed H/V ratios istherefore sufficient for an application ofthe method in seismic hazard analysis for aspecific site.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Aki, K., 1957, Space and time spectra of stationary stochastic waves with special reference to microtremors, Bull. Earthquake Res. Inst., Tokyo Univ. 35, 415–457.
Fäh, D., Kind, F. and Giardini, D., 2001, A theoretical investigation of average H/V ratios, Geophys. J. Int. 145, 535–549.
Florsch, N., Fäh, D., Suhadolc, P. and Panza, G.F., 1991, Complete synthetic seismograms for high frequency multimode SH–waves, Pageoph 136, 529–560.
Horike, M., 1985, Inversion of phase velocity of long–period microtremors to the S–wave–velocity structure down to the basement in urbanized areas, J. Phys. Earth 33, 59–96.
Kind, F., Fäh, D. and Giardini, D., 2001, Application of an array technique to Ambient Vibrations, Geophys. J. Int., submitted.
Kind, F., 2002, Development of Microzonation Methods: Application to Basle, Switzerland, PhD thesis No.14548, Swiss Federal Institute of Technology, Zurich.
Lachet, C. and Bard, P.–Y., 1994, Numerical and theoretical investigations on the possibilities and limitations of Nakamura's technique, J. Phys. Earth 42, 377–397.
Lermo, J. and Chavez–Garcia, J., 1994, Are microtremors useful in site response evaluation? Bull. Seism. Soc. Am. 84, 1350–1364.
Maurer, H.R., Van der Veen, M., Giudici, J. and Springman, S., 1999, Determining elastic soil properties at small strains, submitted to Proceedings SAGEEP meeting, 15.3.–19.3. 1999, Oakland, U.S.A.
Nakamura, Y., 1989, A method for dynamic characteristics estimation of subsurface using microtremor on the ground surface, QR of RTRI 30, 25–33.
Panza, G.F., 1985, Synthetic seismograms: The Rayleigh waves modal summation, J. Geophys. 58, 125–145.
Panza, G.F. and Suhadolc, P., 1987, Complete strong motion synthetics, In: Bolt, B.A. (ed.), Seismic strong motion synthetics, Academic Press, Computational Techniques, 4, pp. 153–204.
Satoh, T., Kawase, H., Iwata, T. Higaski, S., Sato, T., Irikura, K. and Huang, H.C., 2001, S–wave velocity structure of Taichung basin, Taiwan estimated from array and single–station records of microtremors, Bull. Seism. Soc. Am. 91, 1267–1282
Yamanaka, H., Takemura, M., Ishida, H. and Niea, M., 1994, Characteristics of long–period microtremors and their applicability in exploration of deep layers, Bull. Seism. Soc. Am. 84, 1831–1841.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Fäh, D., Kind, F. & Giardini, D. Inversion of local S-wave velocity structures from average H/V ratios, and their use for the estimation of site-effects. Journal of Seismology 7, 449–467 (2003). https://doi.org/10.1023/B:JOSE.0000005712.86058.42
Issue Date:
DOI: https://doi.org/10.1023/B:JOSE.0000005712.86058.42