Tsunami Elemental Signatures in the Samoan Islands: A Case Study

Abstract

This study uses Itrax X-ray fluorescence element data available for Samoan sediment cores, obtained from three separate locations after the 2009 tsunami in this region, to identify its elemental characteristics in the coastal landscape. Normalization of data using Al reveals a distinct elevated elemental signature for this event at sites which had experienced inundation. This provides benchmarks for identifying comparable signatures in the core profiles which likely represent past tsunamis to have inundated each site. Such information can support a better understanding of the frequency and longer-term threats posed by tsunamis in this region. The findings presented are consistent with benchmark tsunami Itrax observations at Little Pigeon Bay following the 2016 Kaikōura Tsunami in New Zealand. Furthermore, they reinforce the normalization of Itrax element data using Al to interpret tsunami episodes in sediment cores, in addition to using high resolution core scanning as an effective non-destructive tool to screen likely tsunami deposits for more targeted multi-proxy analysis.

Effects of Source Faulting and Fringing Reefs on the 2009 South Pacific Tsunami Inundation in Southeast Upolu, Samoa

“…In the aftermath of the event, extensive investigation of the tsunami source and wave characteristics were undertaken based on seismic and GPS records, field surveys, and numerical modeling (e.g., Beavan et al., 2010; Dilmen et al., 2018; Fan et al., 2016; Goff & Dominey‐Howes, 2011; Han et al., 2019; Hossen et al., 2017; Lay et al., 2010; E. A. Okal et al., 2010; Roeber et al., 2010; Williams, 2019; Wood et al., 2018; Yamazaki et al., 2011; Zhou et al., 2012). Previous efforts to reconstruct tsunami characteristics in Samoa were limited to simulating wave initiation and propagation up to the reef edge (e.g., Franchello & Annunziato, 2012; Fritz et al., 2011; E. Okal et al., 2011; Zhou et al., 2012).…”

Effects of source faulting and fringing reefs on the 2009 South Pacific tsunami inundation in southeast Upolu, Samoa

“…In the aftermath of the event, extensive investigation of the tsunami source and wave characteristics were undertaken based on seismic and GPS records, field surveys, and numerical modeling (e.g., Beavan et al, 2010;Dilmen et al, 2018;Fan et al, 2016;Goff & Dominey-Howes, 2011;Han et al, 2019;Hossen et al, 2017;Lay et al, 2010;E. A. Okal et al, 2010;Roeber et al, 2010;Williams, 2019;Wood et al, 2018;Yamazaki et al, 2011;Zhou et al, 2012). Previous efforts to reconstruct tsunami characteristics in Samoa were limited to simulating wave initiation and propagation up to the reef edge (e.g., Franchello & Annunziato, 2012;Fritz et al, 2011;Zhou et al, 2012).…”