Japan Geoscience Union Meeting 2015

Presentation information


Symbol H (Human Geosciences) » H-CG Complex & General

[H-CG35] Interdisciplinary approach to earth's changing surface

Wed. May 27, 2015 6:15 PM - 7:30 PM Convention Hall (2F)

Convener:*Naofumi Yamaguchi(Center for Water Environment Studies, Ibaraki University), Hajime Naruse(Department of Geology and Mineralogy, Graduate School of Science, Kyoto University), Koji Seike(Atmosphere and Ocean Research Institute, University of Tokyo), Hideko Takayanagi(Institute of Geology and Paleontology, Graduate School of Science, Tohoku University), Masayuki Ikeda(Shizuoka University)

6:15 PM - 7:30 PM

[HCG35-P05] Subsurface structure around Oumi basin

*Naoko KITADA1, Hiroko ITO1, Naoto INOUE1, Muneki MITAMURA2, Keiji TAKEMURA3 (1.Geo-Resarch Institute, 2.Osaka City Univ., 3.Kyoto Univ.)

Keywords:alluvium, borehole, database, sedimentary environment

Omi Basin is located in the central part of Shiga Prefecture which includes the largest lake in Japan called Lake Biwa. So as to clarify both geotechnical and geological properties in this area, Kansai Geo-informatics Network (KG-NET) has collected about 14,600 borehole data to add the exiting "Kansai Geo-informatics Database"(GI-base). In this study, the sedimentary facies of the shallow subsurface strata have been introduced by using GI-base and some standard borehole data.
Because the topographical and geological characteristics of the basin obviously change for each local area, the sedimentary facies are also complicate and difficult to be generally evaluated. So the discussion has been focused about mainly the eastern and western part of Lake Biwa.
The eastern part of Lake Biwa has the largest plain in the Basin. The freshwater clays distribute continuously under the deltaic deposit in the southeast, while the beach ridge and its back marsh are formed along the northeast lakeside. The soil properties of the reclaimed lagoons and back marsh are specially soft and weak clays.