Goto et al. published a short paper on the Japan 2011 tsunami and implications for paleotsunami research in Marine Geology: Goto, K., Chagué-Goff, C., Fujino, S., Goff, J., Jaffe, B., Nishimura, Y., Richmond, B., Sugawara, D., Szczuciński, W., Tappin, D.R., Witter, R.C., Yulianto, E., 2011: New insights of tsunami hazard from the 2011 Tohoku-oki event. Marine Geology, 290, 1-4, 46-50.
The paper describes the tsunamites (sand and muds) deposited during the 2011 tsunami, especially concerning run-off distance and sediment types and thicknesses. The authors discuss chemical (chloride from the sea-salt) and biological markers (not discussed in detail) associated with tsunamites. They conclude that evidence for previous tsunamis (e.g., the 869 AD Jogan event) was underestimated, which resulted in a lower risk estimation from tsunami hazard.
I wonder if the increased chloride content of tsunamites compared to the surrounding “natural” sediments is still detectable after hundreds or thousand of years after deposition. Does anyone have an idea or paper about that?
Update: Witold Szczuciński kindly pointed out this paper about the geochemical footprint of tsunamis:
Chagué-Goff, C., 2010: Chemical signatures of palaeotsunamis: A forgotten proxy? Marine Geology 271, 67-71.
Cl and Na shouldn’t be the best indicators for plaeotsunamis, especially if the tsunamites are old. The author concludes that “Elements, which have successfully been used as proxies for tsunami inundation are S, Cl, Na, Sr, Ba and Ca in sediments, as well as SO4 2−, Na+, Cl−, Ca2+ and Mg2+ in interstitial water and Ti as indicator of high energy.” (Chagué-Goff, 2010, p.71)