Project/Area Number |
09304047
|
Research Category |
Grant-in-Aid for Scientific Research (A)
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Allocation Type | Single-year Grants |
Section | 一般 |
Research Field |
Geology
|
Research Institution | Chiba University |
Principal Investigator |
ITO Tanio Chiba Univ., Earth Sci., Professor, 理学部, 教授 (50111448)
|
Co-Investigator(Kenkyū-buntansha) |
MURATA Akihiro Tokushima Univ.Geol.Dept., Associate Professor, 総合科学部, 助教授 (20143373)
YAMAKITA Satoshi Miyazaki Univ., Geol.Dept., Associate Professor, 教育学部, 助教授 (80210342)
HIRATA Naoshi Univ.Tokyo, Earthq.Res.Inst., Professor, 地震研究所, 教授 (90156670)
TSUMURA Noriko Chiba Univ., Earth Sci., Research Associate, 理学部, 助手 (00272302)
SHINOHARA Masanao Chiba Univ., Earth Sci., Associate Professor, 理学部, 助教授 (90242172)
久富 邦彦 和歌山大学, 教育学部, 助教授 (30165104)
|
Project Period (FY) |
1997 – 1998
|
Project Status |
Completed (Fiscal Year 1998)
|
Budget Amount *help |
¥37,400,000 (Direct Cost: ¥37,400,000)
Fiscal Year 1998: ¥5,900,000 (Direct Cost: ¥5,900,000)
Fiscal Year 1997: ¥31,500,000 (Direct Cost: ¥31,500,000)
|
Keywords | Seismic reflection / Seismic refraction / Deep-seated reflector / Butsuzo Tectonic Line / Median Tectonic Line / Kii Peninsula / 付加体 |
Research Abstract |
The seismic reflection I refraction study was made along two lines A and B from the Sambagawa through the Chichibu to the Shimanto belts across the Butsuzo Tectonic Line in the western Wakayama, Kii peninsula, , where the typical structural zonation occurs in the Outer Zone of southwest Japan. The total length of the seismic lines is 21 km. The main specifications are as follows : Receiving point (RP) interval = 50 m, Total number of RP = 422, Channel = 280, Receivers = 9/1RP, Source = 3 Vibroseises, Shot point (SP) interval = 200 m, Total number of RP = 422, Sweep length = 16.0 sec., Number of sweep = 30, Sweep frequency = 6 40 Hz, Recorder = G-DAPS 4, Sampling rate = 4.0 msec., Recording length = 20.0 sec. Although the seismic lines run on rugged topography that is common in Japan, the seismic data set is excellent in quality. The preliminary brute stack sections exhibit two major horizontal / subhorizontal reflectors of TWT 2.5 and 4.5 sec. The 2.5 sec. reflector may correspond to the basal part of the Butsuzo Tectonic Line which thrusts the Chichibu belt over the Cretaceous beds in the Shimanto belt, whereas the 4.5 sec. to that of the Gobo-Hagi tectonic Line which which thrusts the Cretaceous over the Paleogene beds in the Shimanto belt. As the common depth points, however, concentrate insufficiently along and around the stacking lines, the. seismic profiles are not so high in quality. The further improvement of data processing is required.
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