**3. Results and interpretations**

The Samoan cores show comparable elemental profile trends to those observed at Little Pigeon Bay when normalized against Al (**Figure 2**). At Little Pigeon Bay, a sharp sedimentary contact denoted by distinct elevations in elemental levels

#### **Figure 2.**

*Selected Itrax data (normalized over Al) for profiles S1 (Ma'asina), S2 (Manono-uta) and S3 (Lano). Time markers shown at Ma'asina are based on 210Pb constant initial concentration (CIC) and constant rate of supply (CRS) ages up to 11 cm profile depth provided in [19] and are forecast using a power function curve. Calibrated 14C age shown at Lano was sourced from [19]. All time markers presented are indicative only and provide tentative benchmarks for interpretation.*

associated with the 2016 event directly overlies the pre-inundated sediment surface. This provided a benchmark tsunami signature at this site, with similar characteristic signals observed deeper in the cores [8].

However, significant data gaps are observed in the Samoan profiles, especially the Lano and Manono-uta cores. These gaps are associated with the Al counts approaching detection limit and/or non-detection. In contrast, the non-detection of Al in the Ma'asina core accounted for only 7% of the total dataset compared with 61 and 63% for the Lano and Manono-uta cores, respectively.

At Manono-uta, distinct elevated signals are observed at ~0.06 m depth for most of the detected elements except Si. The Si trend exhibits a relatively low and stable background elemental signal with no discernable changes in the profile, indicating that offshore and terrestrial sources for Si are not abundant at this site. Manono-uta was inundated by the 2009 tsunami with flow depths up to 2 m in some areas, including the core site in this study, with the elevated signals at the core surface likely representing the elemental signature of this event. Characteristic signals deeper in the profile which appear lower in magnitude than the 2009 signature are likely representing: (1) smaller events; (2) other types of coastal processes (e.g., storm surge or rainfall-related flooding); and/or (3) artifacts associated with interpolation and matrix effects.

Comparable trends are observed at Ma'asina where a distinct elevated signal occurs at ~0.05 m. This site was also inundated during the 2009 tsunami which suggests that the elevated signal is representing this event. 210Pb ages available for this core in [19] suggests that similar signals observed at depth could be representing historical tsunamis such as the 1960 Valdivia tsunami, or storm surges which are known to have impacts this area (such as the 1991 Tropical Cyclone Val).

At Lano, elevated elemental signals are not apparent at the surface of the core. Compared with the sites at Manono-uta and Ma'asina, this site was not inundated during the 2009 tsunami [15], thus a signal for this event would not be expected. Interestingly, a strongly elevated signal is observed at 1.4 m which is consistent with a distinct calcareous sand unit described in [19]. An available calibrated 14C age of AD 1185–1280 at 1.39 m obtained from plant fragments within this unit [19], indicates that a potentially significant inundation event might have occurred during, or after, this period.
