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Figure 1: A geotechnical profile in Kirovakan and the corresponding damage statistics during 1988 Armenia earthquake (after Yegian et al., 1994c).

  
Figure 2: Geometry and material properties of the two-dimensional basin model.

  
Figure 3: (a) Computational domain for the analysis of the basin model (top layer in Zone 2 not shown); absorbing boundary on I-I; effective forces applied on II-II; (b) Finite element mesh; (c) Partitioned mesh for parallel computing.

  
Figure 4: (a) Scaled free field reference rock accelerogram for the incoming wave at depth for Kirovakan simulation; (b) Amplitude of its Fourier transform.

  
Figure 5: (a) Synthetic accelerograms corresponding to 2D simulation of 1988 Armenia Earthquake for several surface points along the valley identified on Fig. 2; (b) Spatial variation of peak ground acceleration along the entire valley (corresponding to both 2D and 1D simulations).

  
Figure 6: Fourier spectral ratio (FSR) at site F in Zone 2 (corresponding to both 2D and 1D simulations). Equivalently, normalized amplitude of the response at F due to a steady-state harmonic vertically incident wave.

  
Figure 7: Fourier spectral ratio as a simultaneous function of position of observer and frequency. Top: 2D simulation; Bottom: 1D simulation.

  
Figure 8: Extremum and nodal points for several mode shapes and , and their corresponding frequencies and , for a homogeneous rectangular valley. These points are joined by the extremum line, and the nodal line, respectively.

  
Figure 9: Pseudo-acceleration structural response spectra for five percent critical damping using ground motion synthetics from 1D and 2D simulations. (a) Response spectra for three sites in Kirovakan shown on insert and one in Leninakan, denoted by K and L, respectively; (b)--(d) Response along entire valley of Kirovakan, for three different natural frequencies.

  
Figure 10: Pseudo-acceleration response spectra for five percent critical damping, as a simultaneous function of the location of the structure and its natural frequency. Top: For 2D simulation of 1988 Armenia Earthquake; Bottom: For corresponding 1D simulation.