Development of Ground Motion Input in 2D Finite Difference Analysis of the Case History of CentrePort, Wellington, in the Kaikōura 2016 Mw7.8 Earthquake

We performed 2D dynamic finite-difference analyses, to understand the effects of gravelly soil liquefaction on the performance of CentrePort, under the Kaikōura, New Zealand, 2016 M_w7.8 earthquake, and compared the results to field observations. In this study, we focused on the development of appropriate seismic loading input used in the analysis. Ground acceleration time history recordings are available from eight strong motion stations (SMS) nearby. We selected the recording from station POTS as the “rock outcrop” motion, and the PIPS and CPLB recording as the “target” motions that we desire to match. The selections were made based on soil stratigraphy, and shear wave velocity (Vs) profiles at the site of CentrePort, and near the recording stations. To verify that the selection was appropriate, we then performed 1D equivalent linear site response analysis. In the site response analysis, we considered the mean Vs profile across the site, as well as the ±σ Vs profiles. The 5%-damped spectral accelerations at the top of the 1D soil column were compared to that of the PIPS and CPLB recording. Additionally, we applied frequency filtering to the input motion to reduce the computational cost of the model.