TY - JOUR
T1 - Dating tsunami deposits
T2 - Present knowledge and challenges
AU - Ishizawa, Takashi
AU - Goto, Kazuhisa
AU - Yokoyama, Yusuke
AU - Goff, James
N1 - Funding Information:
We would like to thank Dr. Florsheim for kind editing of this manuscript. We also thank Dr. Pedro Costa and an anonymous reviewer for their constructive comments. This research was supported by research funding from JSPS KAKENHI Grant Number JP17H02971 , JP15KK0151 , and JP17H01168 .
Publisher Copyright:
© 2019 Elsevier B.V.
PY - 2020/1
Y1 - 2020/1
N2 - 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.
AB - 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.
KW - Age-depth modeling
KW - Bayesian statistics
KW - Sample selection
KW - Tsunami deposit
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U2 - 10.1016/j.earscirev.2019.102971
DO - 10.1016/j.earscirev.2019.102971
M3 - Review article
AN - SCOPUS:85074785997
SN - 0012-8252
VL - 200
JO - Earth-Science Reviews
JF - Earth-Science Reviews
M1 - 102971
ER -