Chatham Island in the southwest Pacific Ocean is exposed on all sides to potential tsunami
impact. In historical time, tsunamis are known to have inundated the coast on several
occasions, with the largest event in 1868. Coastal dunes along the northeast coast of
Chatham Island preserve sedimentary evidence of this and possibly earlier tsunami events,
as localised gravel lags. However, these deposits lack a clear stratigraphic context and
establishing their age is difficult. This study examines the sediment record in a freshwater …