論文

2020年1月1日

Dating tsunami deposits: Present knowledge and challenges

Earth-Science Reviews
  • Takashi Ishizawa
  • ,
  • Kazuhisa Goto
  • ,
  • Yusuke Yokoyama
  • ,
  • James Goff

200
DOI
10.1016/j.earscirev.2019.102971

© 2019 Elsevier B.V. Dating approaches for fine sediment tsunami deposits can be divided into two categories: (1) dating directly using materials from within a tsunami deposit, and (2) dating indirectly using materials from above and below it. For the former, Optically Stimulated Luminescence (OSL) dating has a possible advantage in that is can directly date the burial age of sediments laid down by a tsunami. However, because of methodological limitations, OSL dating cannot always provide a reliable age. Although 14C and U–Th dating of reworked material from within a tsunami deposit are possible means of determining the age of the event, the results merely represent a maximum age of deposition. For these reasons, dating is commonly achieved indirectly from 14C dates taken from samples in sections immediately above and below a tsunami deposit. However, indirectly dated results do not provide a precise timing of the event. Therefore, there are distinct limitations in the ability to obtain high precision dating of past tsunamis. Recent methodological developments including the application of Bayesian statistical analysis to radiocarbon dating results and the selection of appropriate dating materials has significantly improved the accuracy of age determination by reducing errors. This review presents several methodological improvements that have enhanced tsunami deposit age estimation. The most important points for a more precise tsunami age estimation are the numbers of 14C samples dated coupled with the use of Bayesian statistical analysis. These points are applicable not only to tsunami deposits but also to many other past geohazard events.

リンク情報
DOI
https://doi.org/10.1016/j.earscirev.2019.102971
Scopus
https://www.scopus.com/record/display.uri?eid=2-s2.0-85074785997&origin=inward
URL
https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85074785997&origin=inward