Obtaining shear wave input for 1D site response analysis: a frequency adjustment method based on strong motion records – part II: application to sites and the 2011 Tohoku earthquake

This study validates a frequency-domain method to derive incident wavefields from strong motion records for 1D site response analysis. Using site-specific adjustment coefficients <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>ζ</mml:mi> </mml:math> , seismic waves are modified for single- and multi-layer soils. The Adjusted Wave Input Method (AWIM) significantly outperforms the traditional Wave Input Method (WIM), achieving &gt; 95 % accuracy in velocity/displacement predictions when benchmarked against the Vibration Input Method (VIM). Application to the 2011 Tohoku Earthquake records at three KiK-net sites (low/medium/high stiffness) confirms AWIM’s robustness: surface response spectra align closely with field data. This method improves the accuracy of the wave input method, especially for soft soil.