Multi-channel seismic reflection survey in Tokyo Bay.
A multi-channel seismic reflection survey in Tokyo Bay was carried out along 6 lines of 130 km in total length by the Hydrographic Department on March 1982. For this survey, two 500 cubic inches air guns as sonic sources and a 24 channel streamer cable of 1200 m length as receiver were used. Acquired data was processed by the methods of CDP stacking, velocity analysis, time migration, depth conversion, and others. Then a 12-fold stack section, a migrated time section and a migrated depth section for each line were made after these processings. We can clearly find the geological structure beneath Tokyo Bay to about 3 km depth on these sections. The geological structure of Tokyo Bay is summarized as follows; i ) Pre-Neogene basement rock in the Kanto area is found at 2-3 km depth at the center of the Bay, and more them 3.4 km depth in the southern part of the Bay. ii) Neogene and Quaternary layers of 2-3.4 km thick cover the Pre-Neogene basement. From the lower to upper layer, the section of maximum thickness moves from the southern to the northeastern part of the Bay. iii) A fault with strike of N50-55'W found at the inner part of the Bay displaces Pre-Neogene basement down to 420 m on the north. Some normal faults slightly displacing the Neogene layer are also recognized in the southern part of the Bay. iv) Fold structure is recognized at Nakanose in the southern part of the Bay. v) Based on the correlation with deep boring data around Tokyo Bay, it is supposed that Neogene and Quarternary layers are divided into 5 layers (TA-TE); TA and TB correspond to Recent and Pleistocene, TC to Pliocene,and TD and TE to Miocene, respectively.
| Main Author: | |
|---|---|
| Format: | Journal Contribution biblioteca |
| Language: | Japanese |
| Published: |
1984
|
| Online Access: | http://hdl.handle.net/1834/16199 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| Summary: | A multi-channel seismic reflection survey in Tokyo Bay was carried out along 6 lines of 130 km in total length by the Hydrographic Department on March 1982. For this survey, two 500 cubic inches
air guns as sonic sources and a 24 channel streamer cable of 1200 m length as receiver were used.
Acquired data was processed by the methods of CDP stacking, velocity analysis, time migration, depth conversion, and others. Then a 12-fold stack section, a migrated time section and a migrated depth section for each line were made after these processings. We can clearly find the geological structure beneath Tokyo Bay to about 3 km depth on these sections.
The geological structure of Tokyo Bay is summarized as follows;
i ) Pre-Neogene basement rock in the Kanto area is found at 2-3 km depth at the center of the Bay, and more them 3.4 km depth in the southern part of the Bay.
ii) Neogene and Quaternary layers of 2-3.4 km thick cover the Pre-Neogene basement. From the lower to upper layer, the section of maximum thickness moves from the southern to the northeastern part of the Bay.
iii) A fault with strike of N50-55'W found at the inner part of the Bay displaces Pre-Neogene basement down to 420 m on the north. Some normal faults slightly displacing the Neogene layer are also recognized in the southern part of the Bay.
iv) Fold structure is recognized at Nakanose in the southern part of the Bay.
v) Based on the correlation with deep boring data around Tokyo Bay, it is supposed that Neogene and Quarternary layers are divided into 5 layers (TA-TE); TA and TB correspond to Recent and Pleistocene, TC to Pliocene,and TD and TE to Miocene, respectively. |
|---|