No full text
Unpublished conference/Abstract (Scientific congresses and symposiums)
A history of mass transport complexes related to eruptions and earthquake shaking: the case of Lake Motosu (Japan).
Lamair, Laura; Hubert, Aurelia; El Ouahabi, Meriam et al.
2016BELQUA
 

Files


Full Text
No document available.

Send to



Details



Keywords :
seismic reflection; lake motosu; MTDs
Abstract :
[en] The QuakeRecNankai project focuses on geological records of paleoearthquakes along the Nankai-Suruga subduction zone, south central Japan. In the framework of the project, we investigated the Fuji Five Lakes, located at the eastern end of the Nankai-Suruga Trough. Here, we present results from Lake Motosu, the deepest of the Fuji Five Lakes (max. depth 122 m), including seismic reflection profiles, gravity cores and preliminary results of 6.8 m long piston core. We identify mass transport deposits and turbidites possibly triggered by earthquakes. We study the lake sedimentary architecture and the Holocene sedimentation with a high resolution GEOPULSE pinger system. A seismic grid with total length of 39 km covered the lake. We identify a specific seismic horizon that may be related to the Aokigaraharamarubi lava flow (864 A.D.). Strong reflectors may also correlate with tephra layers from Oniwa-Okuniwa eruptions (620-790 A.D). In the western part of the lake, the seismic reflection profile reveals a change after the proposed Oniwa-Okuniwa eruptions in terms of volume and length of mass transport deposits. Large mass-transport deposits occurring before the eruptions are characterized by chaotic seismic facies. After the eruptions, the mass-transport deposits are much smaller and are characterized by transparent seismic facies attributed to turbiditic flow. Six gravity cores (max. 90cm long) provide samples of the lake bottom sediments. In these cores, turbidites and megaturbidites were identified based on facies analyses, combined with X-ray scanning, geophysical properties, grain-size analysis, mineralogy and XRF. During the period between the Oniwa-Okuniwa eruptions and the Aokigaraharamarubi lava flow (620-864 A.D), several lava flows occurred in the northern part of Mount Fuji and drastically modified the catchment of Lake Motosu. The decreasing of the size of catchment led to a decreasing of sedimentary yield in the lake. The change in the sedimentation rate could partly explain why we have a change in the type of mass transport deposit. Additionally, analyses were performed to define the minimum shaking intensity required to destabilize the slope. To assess slope stability, we investigated the clay content and the clay mineralogy of samples taken along the slope. In this presentation, we discuss the link between eruptions of Mount Fuji, decreasing of the size of the catchment, sedimentation rate and earthquake shaking.
Disciplines :
Earth sciences & physical geography
Author, co-author :
Lamair, Laura ;  Université de Liège > Département de géographie > Géomorphologie et Géologie du Quaternaire
Hubert, Aurelia  ;  Université de Liège > Département de géographie > Géomorphologie et Géologie du Quaternaire
El Ouahabi, Meriam  ;  Université de Liège > Département de géologie > Argiles, géochimie et environnements sédimentaires
Boes, Evelien;  Ghent university
Garrett, Ed;  Geological survey of Belgium
Heyvaert, Vanessa;  Geological survey of Belgium
Yamamoto, Shinya;  Mount Fuji Research Institute
Nakamura, Atsunori;  6National Institute of Advanced Industrial Science and Technology (AIST)
Miyairi, Yosuke;  7University of Tokyo > Atmosphere and Ocean Research Institute
Yokoyama, Yusuke;  University of Tokyo > Atmosphere and Ocean Research Institute
De Batist, Marc;  Ghent university
Language :
English
Title :
A history of mass transport complexes related to eruptions and earthquake shaking: the case of Lake Motosu (Japan).
Publication date :
04 March 2016
Event name :
BELQUA
Event place :
Bruxelles, Belgium
Event date :
4 mars 2017
Available on ORBi :
since 19 May 2017

Statistics


Number of views
71 (2 by ULiège)
Number of downloads
0 (0 by ULiège)

Bibliography


Similar publications



Contact ORBi