Offshore wind energy is rapidly expanding to earthquake prone regions, with design to seismic loading becoming a primary concern. This is especially relevant to monopiles, which are the preferred option in shallow to medium water depths at present. This paper presents centrifuge tests of a monopile foundation and turbine tower subjected to low and high frequency earthquakes. The experiment reproduces calm air con-ditions, meaning that no lateral wind load was considered. Low frequency earthquakes were found to cause excitation of the topmost part of the superstructure, whereas high frequency earthquakes generated strong res-onance effects at the base. Further data analysis suggests that high frequency earthquake shaking can trigger liquefaction of the soil surrounding the monopile, which may in turn lead to differential settlement of the tur-bine. This is translated into significant rotation of the structure that can potentially exceed the allowable SLS rotation recommended by the technical guidelines.