The seismic failure of an old quay wall, built in 1932, located in the Port of Iquique during the Mw 8.2 April 1, 2014, Pisagua, Chile, earthquake is studied. A geotechnical exploration, including boreholes, CPT soundings, and surface-based geophysical techniques, was performed to characterize the materials forming the wharf. The data and field observations are then analyzed and used to develop a geotechnical model of two cross-sections modeled in Plaxis2D, to conclude which is the most likely failure mechanism under a dynamic analysis. The results are compared against the deformations measured in a number cross sections of the wharf, suggesting that the failure can be explained by a combined effect of the dynamic increase in lateral earth pressures and the base rotation of the confining walls due to the lack of proper compaction of the rockfill prism below the confining walls.