9:30 AM - 9:45 AM
[MGI34-03] Release of three-dimensional geological map of central Tokyo
Keywords:three-dimensional geological map, borehole logs, DEM, urban area
For promoting utilization of geo-information in urban areas, Geological survey of Japan (GSJ) has carried out the three-dimensional (3D) urban geological mapping project. In this project, we create a 3D geological map to a depth of several tens of meters using borehole logs obtained from drilling surveys for scientific research and public construction work. Additionally, we develop a web system for sharing 3D geo-information. In the spring of 2021, the 3D geological map covering the 23 special wards of Tokyo will be released as a cooperative work with the Civil Engineering Support and Training Center, Tokyo Metropolitan Government (CETC) on the Internet.
The 3D geological map of central Tokyo is the integrated map of topographical information and geological information. With regard to topographical information, we have created a landform classification map, which comprised with 11 categories, using geospatial data, such as digital elevation models (DEMs), aerial photos, and geological maps. With regard to geological information, we have performed stratal correlation of about 50 thousand borehole logs created for public construction work, which are provided by CETC, using a standard stratigraphic framework beneath central Tokyo established based on high-quality stratigraphic data obtained from drilling surveys and laboratory works by GSJ. The GSJ stratigraphic data includes detailed core descriptions (sedimentary facies, marker tephra layers, and fossils); age measurement; and PS velocity and density logging. Further, based on the result of stratal correlation, we have generated DEMs of basal surfaces of geological layers beneath central Tokyo and constructed a surface-based 3D geological model, which has 10 geological layers.
The 3D geological map of central Tokyo will be open to the public on the website “Urban Geological Map” (https://gbank.gsj.jp/urbangeol/). On the website, users can browse the GSJ stratigraphic data, visualize the borehole log images used for mapping and the geological map in 3D, and generate a vertical cross-section image of subsurface geological structure along arbitrary line.
In this presentation, we will talk about an outline of the 3D mapping project and the result of central Tokyo.
The 3D geological map of central Tokyo is the integrated map of topographical information and geological information. With regard to topographical information, we have created a landform classification map, which comprised with 11 categories, using geospatial data, such as digital elevation models (DEMs), aerial photos, and geological maps. With regard to geological information, we have performed stratal correlation of about 50 thousand borehole logs created for public construction work, which are provided by CETC, using a standard stratigraphic framework beneath central Tokyo established based on high-quality stratigraphic data obtained from drilling surveys and laboratory works by GSJ. The GSJ stratigraphic data includes detailed core descriptions (sedimentary facies, marker tephra layers, and fossils); age measurement; and PS velocity and density logging. Further, based on the result of stratal correlation, we have generated DEMs of basal surfaces of geological layers beneath central Tokyo and constructed a surface-based 3D geological model, which has 10 geological layers.
The 3D geological map of central Tokyo will be open to the public on the website “Urban Geological Map” (https://gbank.gsj.jp/urbangeol/). On the website, users can browse the GSJ stratigraphic data, visualize the borehole log images used for mapping and the geological map in 3D, and generate a vertical cross-section image of subsurface geological structure along arbitrary line.
In this presentation, we will talk about an outline of the 3D mapping project and the result of central Tokyo.