Impact of long-duration earthquakes on site response: comparison of 1d and 3d approaches

Abstract

This study presents a comparative analysis of multidirectional site response modeling conducted for a well-instrumented downhole array in Alaska, examining seven long-duration earthquake events. While traditional one-dimensional (1D) analyses provide valuable insight into vertical wave propagation, they often simplify real conditions by neglecting the full range of seismic input components that may influence ground motion characteristics. By incorporating all three earthquake directions as East-West, North-South, and Vertical in a multidirectional site response approach, we aim to achieve a more accurate evaluation of site amplification. The results reveal distinct differences in modelled ground motions between three-dimensional and one-dimensional models across various soil depths, demonstrating the improved reliability provided by a multidirectional framework. These findings emphasize the necessity of employing more comprehensive modeling strategies, particularly in high-seismicity regions like Alaska