Inverse analysis of weak and strong motion downhole array data from the Mw7.0 Sanriku-Minami earthquake

Abstract A hybrid optimization scheme, comprising a genetic algorithm in series with a local least-squares fit operator, is used for the inversion of weak and strong motion downhole array data obtained by the Kik-Net Strong Motion Network during the M w 7.0 Sanriku-Minami Earthquake. Inversion of low-amplitude waveforms is first employed for the estimation of low-strain dynamic soil properties at five stations. Successively, the frequency-dependent equivalent linear algorithm is used to predict the mainshock site response at these stations, by subjecting the best-fit elastic profiles to the downhole-recorded strong motion. Finally, inversion of the mainshock empirical site response is employed to extract the equivalent linear dynamic soil properties at the same locations. The inversion algorithm is shown to provide robust estimates of the linear and equivalent linear impedance profiles, while the attenuation structures are strongly affected by scattering effects in the near-surficial heterogeneous layers. The forward and inversely estimated equivalent linear shear wave velocity structures are found to be in very good agreement, illustrating that inversion of strong motion site response data may be used for the approximate assessment of nonlinear effects experienced by soil formations during strong motion events.

[1]  Jean-Michel Renders,et al.  Hybridizing genetic algorithms with hill-climbing methods for global optimization: two possible ways , 1994, Proceedings of the First IEEE Conference on Evolutionary Computation. IEEE World Congress on Computational Intelligence.

[2]  Vincent P. Drnevich,et al.  Shear modulus and damping in soils , 1972 .

[3]  G W Housner,et al.  COMPETING AGAINST TIME: REPORT TO GOVERNOR GEORGE DEUKMEJIAN , 1990 .

[4]  Semih S. Tezcan,et al.  A reconnaissance report for the Romanian earthquake of 4 March 1977 , 1978 .

[5]  Jamison H. Steidl,et al.  Attenuation and Velocity Structure for Site Response Analyses via Downhole Seismogram Inversion , 2006 .

[6]  S. Aoi,et al.  New strong-motion observation network : KiK-net , 2000 .

[7]  Eduardo Kausel,et al.  Seismic simulation of inelastic soils via frequency-dependent moduli and damping , 2002 .

[8]  J. Bardet,et al.  Kocaeli, Turkey, earthquake of August 17, 1999 reconnaissance report , 2000 .

[9]  Julius S. Bendat,et al.  Engineering Applications of Correlation and Spectral Analysis , 1980 .

[10]  Mrinal K. Sen,et al.  Nonlinear multiparameter optimization using genetic algorithms; inversion of plane-wave seismograms , 1991 .

[11]  Ahmed Elgamal,et al.  Lotung Downhole Array. II: Evaluation of Soil Nonlinear Properties , 1995 .

[12]  V. Drnevich,et al.  SHEAR MODULUS AND DAMPING IN SOILS: DESIGN EQUATIONS AND CURVES , 1972 .

[13]  N. A. Haskell.  The Dispersion of Surface Waves on Multilayered Media , 1953 .

[14]  W. Thomson,et al.  Transmission of Elastic Waves through a Stratified Solid Medium , 1950 .

[15]  地盤工学会.  Special issue on geotechnical aspects of the January 17 1995 Hyogoken-Nambu Earthquake , 1996 .

[16]  Christopher R. Houck,et al.  Comparison of genetic algorithms, random restart and two-opt switching for solving large location-allocation problems , 1996, Comput. Oper. Res..

[17]  Eduardo Kausel,et al.  An equivalent linear algorithm with frequency- and pressure-dependent moduli and damping for the seismic analysis of deep sites , 2002 .

[18]  T. Satoh,et al.  Inversion of Strain-Dependent Nonlinear Characteristics of Soils Using Weak and Strong Motions Observed by Borehole Sites in Japan , 2001 .

[19]  Rachel E. Abercrombie,et al.  Earthquake source scaling relationships from −1 to 5 ML using seismograms recorded at 2.5‐km depth , 1995 .

[20]  R. Dobry,et al.  Effect of Soil Plasticity on Cyclic Response , 1991 .

[21]  I. M. Idriss,et al.  Influence of Soil Conditions on Ground Motions During Earthquakes , 1969 .

[22]  Shigeo Kinoshita,et al.  Kyoshin Net (K-NET) , 1998 .