Inverse analysis to reconstruct hydraulic conditions of non-steady turbidity currents: Application to an ancient turbidite of the Kiyosumi Formation of the Awa Group, Boso Peninsula, central Japan

This is a Preprint and has not been peer reviewed. This is version 1 of this Preprint.

Downloads

Download Preprint

Authors

Kento Nakao, Hajime Naruse, Shuichi Tokuhashi

Abstract

This study proposes a new method of inverse analysis from ancient turbidites to the non-steady turbidity currents with consideration of multiple grain-size classes. The forward model employed in this study is based on the shallow water equation, and the initial condition of flows are assumed to be the lock-exchange type condition. To obtain a solution of the inverse problem, this study employed the genetic algorithm for finding the optimized initial conditions. The present method successfully estimated the true given initial conditions of the turbidity currents from the artificial data sets of deposits created by the calculation of the forward model. The author also applied the method to the turbidite bed in the Kiyosumi Formation. As a result of inverse analysis, the obtained solution fits well to the observed data of the individual turbidite, providing estimates of the flow velocity, the flow thickness and the sediment concentration of the turbidity current.
The flow thickness and velocity when the turbidity current reached at the downstream end of the study area were reconstructed to be 334.6 m, 0.98 m/s respectively at the location of the downstream end. Result of our analysis is the first example of reconstructing a reasonable conditions of the turbidity current from an ancient turbidite observed in the field, and the method id expected to be applied in various regions in the future.

DOI

https://doi.org/10.31223/X51S3S

Subjects

Earth Sciences, Physical Sciences and Mathematics, Sedimentology

Keywords

Genetic algorithm, \kwd{Genetic algorithm}, \kwd{Inverse analysis}, \kwd{Sediment gravity flow Submarine fan, Turbidite

Dates

Published: 2020-10-21 01:30

Last Updated: 2020-10-21 08:30

License

CC BY Attribution 4.0 International

Additional Metadata

Conflict of interest statement:
None

Add a Comment

You must log in to post a comment.


Comments

There are no comments or no comments have been made public for this article.