Marine Geology Map Series no. 97


Geological Map North of OKUSHIRI ISLAND


1. Preface

This Map contains Geological Map North of OKUSHIRI ISLAND (42˚05'N – 42˚50'N and 138˚50'E – 140˚20'E, Tokyo Datum), 3 Appendices and explanatory notes for these maps. These maps were prepared to be displayed or printed at a scale of 1:200,000.


2. Contents

2.1 Files

This directory is composed of the sub directories and files shown in Table 1.


Table 1   Contents of directories
start_e.html Cover page of this Map in HTML format
 ¥doc¥ Explanatory note files
    geological.pdf Explanatory note of the Geological map in PDF format
    gravmag.pdf Explanatory note of the Gravity and Magnetic anomaly maps in PDF format
    html¥ Explanatory notes in HTML format
        index_e.html Top page of this directory in HTML format
        readme_e.html (this file) About this Geological map
        remark.html Remarks in HTML format
        geological¥ Explanatory note of the Geological map in HTML format
             en¥ HTML files for English version
                index.html Cover page of the explanatory note
             fig¥ Figures and tables in PNG format
        gravmag¥ Explanatory note of the Geomagnetic and gravity anomaly maps
             en¥ HTML files for English version
                index.html Cover page of the explanatory note
             fig¥ Figures and tables in PNG format
 ¥image¥ Images files (Lambert's conformal conic projection)
    geological.png Geological map in PNG format
    legend.png Legend in PNG format
    cross_section.png All cross section in PNG format
    section_a.png Cross section (A-B) in PNG format
    section_c.png Cross section (C-D) in PNG format
    section_e.png Cross section (E-F) in PNG format
    section_g.png Cross section (G-H) in PNG format
    section_i.png Cross section (I-J) in PNG format
    section_k.png Cross section (K-L) in PNG format
    section_m.png Cross section (M-N) in PNG format
    section_o.png Cross section (O-P) in PNG format
    section_q.png Cross section (Q-R) in PNG format
    index_map.png Index map in PNG format
    survey_line.png Survey lines in PNG format
    mag_bw.png Appendix 1 : Geomagnetic Total-intensity Anomaly Map in PNG format (monochrome)
    fga_bw.png Appendix 2 : Free-Air Gravity Anomaly Map in PNG format (monochrome)
    bga_bw.png Appendix 3 : Bouguer Gravity Anomaly Map in PNG format (monochrome)
    mag.png Appendix 1 : Geomagnetic Total-intensity Anomaly Map in PNG format
    fga.png Appendix 2 : Free-Air Gravity Anomaly Map in PNG format
    bga.png Appendix 3 : Bouguer Gravity Anomaly Map in PNG format
    geological.tif Geological map in TIFF format
    cross_section.tif All cross section in TIFF format
    mag_bw.tif Appendix 1 : Geomagnetic Total-intensity Anomaly Map in TIFF format (monochrome)
    fga_bw.tif Appendix 2 : Free-Air Gravity Anomaly Map in TIFF format (monochrome)
    bga_bw.tif Appendix 3 : Bouguer Gravity Anomaly Map in TIFF format (monochrome)
    mag.tif Appendix 1 : Geomagnetic Total-intensity Anomaly Map in TIFF format
    fga.tif Appendix 2 : Free-Air Gravity Anomaly Map in TIFF format
    bga.tif Appendix 3 : Bouguer Gravity Anomaly Map in TIFF format
 ¥map¥ PDF and Adobe® Illustrator® format file (Lambert's conformal conic projection)
    geological.ai Geological map (Including monochrome Appendices)
    geological.pdf Geological map in PDF format (Including monochrome Appendices)
    cross_section.ai All cross section
    mag.ai Appendix 1 : Geomagnetic Total-intensity Anomaly Map (color)
    fga.ai Appendix 2 : Free-Air Gravity Anomaly Map (color)
    bga.ai Appendix 3 : Bouguer Gravity Anomaly Map (color)
 ¥vector¥ Vector data files (Latitude and longitude coordinates)
     shape¥ Shapefile
 path_e.txt List of Directories and files in English (Plain text format).

Sub-directories in vector contain files shown in table 2 for each type of maps




Table 2 　File names of items in map data and attributes of vector data
Type of Map Item File name* Attribute of vector data
Base map Map frame area line ICODE1（Tab.2-1）
Latitudinal and longitudinal coordinates latlon line ICODE1（Tab.2-2）
Depth contour bathy line ICODE1（Tab.2-3）
Coast line coast coast_p polygon ICODE1（Tab.2-4）
coast_l line ICODE1（Tab.2-4）
Geological Map Geologic unit geol geol_p polygon ICODE1, CCODE1（Tab.2-5）
boundary and fault geol_l line ICODE1（Tab.2-5）
Anticlinal axis and Synclinal axis axis line ICODE1（Tab.2-6）

Collapsed slope and debris flow deposits

 col line ICODE1 （Tab.2-7）
Volcanic mound below the seafloor vol line ICODE1（Tab.2-8）
Hummocks in debris avalanche hum hum_p polygon ICODE1, CCODE1（Tab.2-9）
hum_l line ICODE1, CCODE1（Tab.2-9）
Line of cross section cross line ICODE1（Tab.2-10）
Appendix 1 Geomagnetic Total-intensity Anomaly Map mag line ICODE1, ICODE2, CCODE1（Tab.2-11）
Appendix 2 Free-air Gravity Anomaly Map fga line ICODE1, ICODE2, CCODE1（Tab.2-12）
Appendix 3 Bouguer Gravity Anomaly Map bga line ICODE1, ICODE2, CCODE1（Tab.2-13）

*the extension .shp is attached depending on the type of data.

to 2.2 Datum and Projection




Table 2-1　Map frame （area）
Line
Division ICODE1
All 200

to Table 2

Table 2-2　 Latitudinal and longitudinal coordinates （latlon）
Line
Division ICODE1
All 1

to Table 2

Table 2-3　Water depth（bathy）
Line
Water depth（m） ICODE1

to Table 2

Table 2-4　Coastline（coast）
Polygon：coast_p
Division ICODE1
On shore 1
Off shore 2
Line：coast_l
Division ICODE1
Coastline 1
Map area limit 200

to Table 2

Table 2-5　Geological unit, boundary and fault (geol)
Polygon：geol_p
Division Age Geological unit ICODE1 CCODE1
Offshore Quaternary Unit Q 1 Q
Unit Vq 2 Vq
Pliocene Unit p 3 P
Neogene to Early Pliocene Unit M 4 M
Neogene Miocene Unit Vm 5 Vm
Age unknown Acoustic basement 6 Bs
No attribution 0
Onshore Quaternary Sediments 11 qs
Neogene Pliocene 12 n2s
Neogene Miocene 13 n1s
Paleogene 14 pgs
cretaceous 15 ks
Quaternary Volcanic rocks 16 qv
Negene Pliocene 17 n2v
Neogene Miocene 18 n1v
Paleogene 19 pgv
Cretaceous 20 kv
Neogene Mionene Plutonic rocks 21 n1p
Cretaceous 22 kp
Jurassic Accretionary prism 23 jc
No attribution 0
Line：geol_l
Division ICODE1
Unit boundary 1
Inferred unit Boundary 2
Inferred normal fault 3
Reverce fault 4
Reverse fault (concealed) 5
Inferred flexure zone 6
Fault (onshore) 7
Concealed Fault (onshore) 8
Inferred Fault (onshore) 9
Shallower limit of survey line 100
Map area limit 200

to Table 2

Table 2-6　Anticlinal axis and Synclinal axis (axis)
Line
Division ICODE1
Anticlinal axis 1
Anticlinal axis (concealed) 2
Synclinal axis 3

to Table 2

Table 2-7　Collapsed slope and debris flow deposits (col)
Polygon
Division CCODE1
Collapsed slope and debris flow deposits 1

to Table 2

Table 2-8　Volcanic mound below the seafloor (vol)
Polygon
Division CCODE1
Volcanic mound below the seafloor 1

to Table 2

Table 2-9　Hummocks in debris avalanche (hum)
Polygon
Division ICODE1 CCODE1
Hummocks in debris avalanche 1 h
Line
Division ICODE1
boundary 1

to Table 2

Table 2-10　Line of cross section (cross)
Line
Division ICODE1
A-B 1
C-D 2
E-F 3
G-H 4
I-J 5
K-L 6
M-N 7
O-P 8
Q-R 9

to Table 2

Table 2-1!　Geomagnetic Total-intensity Anomaly Map（mag）
Line
Geomagnetic Anomaly（nT） ICODE1
Type ICODE2
Thin line 1
Thick line 2
Type CCODE1
High magnetic anomaly area H
Low magnetic anomaly area L

to Table 2

Table 2-12　Free-air Gravity Anomaly Map（fga）
Line
Free-air Gravity Anomaly（mGal） ICODE1
Type ICODE2
Thin line 1
Thick line 2
Type CCODE1
High gravity anomaly area H
Low gravity anomaly area L

to Table 2

Table2-13　Bouguer Gravity Anomaly Map（bga）
Line
Bouguer Gravity Anomaly（mGal） ICODE1
Type ICODE2
Thin line 1
Thick line 2
Type CCODE1
High gravity anomaly area H
Low gravity anomaly area L

to Table 2

Standard attributes of line and point
Polygon:
Division ICODE1
Distribution 1
Non distribution 0
Line:
Boundary 1
Inferred boundary 2
Shallower limit of survey line 100
Map area limit 200

to Table 2




2.2 Datum and Projection

The GIS vector maps are in latitude and longitude coordinates based on Tokyo Datum.

The Adobe Illustrator maps and the raster maps in PNG, TIFF and PDF (excluding Figures) formats are in Lambert's conformal conic projection with standard parallels at 42˚12' and 42˚43' on Tokyo Datum. However, the coordinate values based on WGS84 are also showned on these maps.

The conversion programs that convert Tokyo Datum to WGS84 are provided in the website of the Hydrographic and Oceanographic Department ( https://www1.kaiho.mlit.go.jp/ ) of Japan Coast Guard. The conversion programs are available in Japanese only as of October, 2007.


3. Utilization Environment

3.1 GIS vector data

The GIS vector map data are in Shapefile formats. In order to display these data, GIS softwares are required.


3.2 Illustrator data

For the Adobe Illustrator map data, the Illustrator version CS2 or later are recommended.


3.3 Raster (image) data

The raster data of the maps are in PNG, TIFF and PDF formats, which can be displayed in image processing software. The PNG formatted data can also be displayed on web browser through the HTML files contained in this Map. The PDF may contain multiple layers. To use all the features of pdf, Adobe Acrobat® is recommended.


3.4 Explanatory notes

The explanatory notes in HTML and PDF format may be accessible via a web browser and PDF viewer.

4. Authors and contributors

Geological Map and Explanatory note OKAMURA Yukinobu (Institute of Earthquake and Volcano Geology)
Appendix and Explanatory note SATO Taichi (Research Institute of Geology and Geoinformation)
Digitization of maps Ohkuma Yohko and Yamaya Tadahiro, (Geoinformation Service Center)
Digitization of explanatory note

Yamaya Tadahiro and Ohkuma Yohko (Geoinformation Service Center)

5. Suggested citation format

OKAMURA, Y. and SATO, T.（2026）Geological Map North of OKUSHIRI ISLAND. Marine Geology Map Series, no. 97, Geological Survey of Japan, AIST, doi:10.50886/0002003443.

OKAMURA, Y.（2026）Geological Map North of OKUSHIRI ISLAND. Marine Geology Map Series, no. 97, Geological Survey of Japan, AIST.

SATO, T.（2026）Geomagnetic Total-intensity Anomaly Map. Geological Map North of OKUSHIRI ISLAND, Appendix 1, Marine Geology Map Series, no. 97, Geological Survey of Japan, AIST.

SATO, T.（2026）Free-Air Gravity Anomaly Map. Geological Map North of OKUSHIRI ISLAND, Appendix 2, Marine Geology Map Series, no. 97, Geological Survey of Japan, AIST.

SATO, T.（2026）Bouguer Gravity Anomaly Map. Geological Map North of OKUSHIRI ISLAND, Appendix 3, Marine Geology Map Series, no. 97, Geological Survey of Japan, AIST.

6. Trademarks

Adobe, Illustrator and Acrobat are either registered trademarks or trademarks of Adobe in the United States and/or other countries.

Reference to above products or any specific corporation names, commercial products or service in this Map does not necessarily constitute or imply an endorsement by GSJ, AIST.



Published by the Geological Survey of Japan, AIST on July 30, 2026.

For further information, contact :

Geological Survey of Japan, AIST

AIST Tsukuba Central 7, 1-1-1, Higashi, Tsukuba, Ibaraki 305-8567, Japan

URL:https://www.gsj.jp/inquiryEN.html


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(C) 2026 AIST