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Nascent plate boundary along the eastern margin of the Japan Sea: testing a new hypothesis by geomorphological methods

日本海东缘新生板块边界：用地貌学方法检验新假设

基本信息

批准号：
60580198
负责人：
IKEDA Yasutaka
金额：
$ 0.32万
依托单位：
Department of Geography, Faculty of Science, University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1985
资助国家：
日本
起止时间：
1985 至 1986
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-60580198/
关键词：
Nascent plate boundary Central Japan Tectonic geomorphology Net slip 中部日本

项目摘要

Kobayashi (1983) and Nakamura (1983) presented a new hypothesis that the boundary between the North American and Eurasian plates has jumped from Central Hokkaido to the eastern margin of the Japan Sea in the recent geologic past. In order to test this hypothesis quantitatively, we determined rate Quaternary rates of slip on major fault zones in Central Japan, where the landward extension of this nascent plate boundary is believed to pass. We revealed that the rates of slip on the Itoigawa-Shizuoka Tectonic Line and the Ina Valley Fault Zone (IVFZ) are as large as 8 mm/yr or more. Although data on slip rates on other faults are not sufficient, the total convergence rate of Central Japan seems larger than that (c.a. 11 mm/yr) predicted by the new hypothesis. We also determined the direction of slip on the IVFZ by a new geomorphological method that we developed; this slip direction (N123+10 deg E), again, is discordant with the east-west convergence direction predicted by the new hypothesis. Thus, we tentatively interpret that the deformation in the middle and southern part of Central Japan is much affected by the collision of the Izu arc, although the possibility of the nascent boundary is not ruled out. Further data on late Quaternary rates of net slip on active faults in the northern part of Central Japan are required for testing this hypothesis.

小林（1983）和中村（1983）提出了一个新的假说，即北美板块和欧亚板块的边界在近代地质史上从北海道中部跳到了日本海东缘。为了定量地检验这一假设，我们在日本中部的主要断裂带上确定了第四纪滑动速率，据信这一新生板块边界的向陆地延伸经过了那里。我们发现，Itoigawa-Shizuoka构造线和伊那谷断层带（IVFZ）的滑动速率高达8毫米/年或更高。虽然关于其他断层的滑动速率的数据不充分，但日本中部的总收敛速率似乎大于此（c.a. 11毫米/年）的新假设预测。我们还确定了一个新的地貌方法，我们开发的IVFZ上的滑动方向;这个滑动方向（N123+10度E），再次，是不一致的东西收敛方向预测的新假设。因此，我们初步解释，在中部和南部地区的变形很大程度上受到碰撞的伊豆弧，虽然不排除新生边界的可能性。进一步的数据晚第四纪净滑动率在日本中部的北方部分的活断层需要测试这一假设。