Evolution and deformation process of the Hidaka Collision Zone, Central Hokkaido, Japan.

日本北海道中部日高碰撞带的演化与变形过程。

基本信息

批准号：
10304033
负责人：
IWASAKI Takaya
金额：
$ 23.42万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10304033/
关键词：
Hidaka Collision Hokkaido Arc Crust Deformation Delamination Reflection 島孤地殻

项目摘要

Our study in 1999 was concentrated in the data processing of seismic reflection data. Our data revealed a clear image of deformation style associated with the arc-arc collision' between the kuril Arc and Northeastern Japan Arc. The obtained reflection section is characterized by(1) strong westward dipping reflector in range of 3-4 sec in IWT under the eastern flank of the Hidaka Mountains,(2) eastward dipping reflector at 2 sec in TWT under the. western flank of the Hidaka Mountains.(3) westward dipping reflector at 4-6 sec in TWT under the middle part of the Hidaka Mountains,and(3) Deep events at 10-1 1 sec in TWT under the eastern edge of the profile.Data collected on off-line recorders were also completed for the refraction/wide-angle crustal study in the collision zone. A combined analysis of the seismic refection and refraction data indicates the following structural features in the surveyed area.(1) In the eastern part of the Hidaka Mountains, a material with a velocity of 5.8-6.0 km/s is almost outcr6pped.(2) The obtained velocity of 5.8-6.0 km/s is rather small as those of the middle crustal or lower crustal rocks which are expected to expose in the Hidaka Mountains. This suggests that the obducted crustal rocks are highly deformed and merged into the surrounding low-velocity upper crustal material.The seismic image obtained forms a part of the delamination-wedge structure associated with the arc-arc collision. The reflectors in the eastern part of the Hidaka Mountaines Is a upper part of the reflective lower crust of the Kuril Arc overriding westward. Our results provide important key for understanding collision process occurring in this region.

我们在1999年的研究集中在地震反射数据的数据处理中。我们的数据显示，与Kuril Arc和日本东北部弧之间的ARC-ARC碰撞相关的变形样式的明确图像。所获得的反射部分的特征是（1）在Hidaka Mountains的东侧的IWT范围内，强烈的向西浸入反射器（2）在TWT下2秒钟的东部浸入反射器（2）。（3）在Hidaka山脉中部，在TWT的4-6秒向西浸入反射器，以及（3）（3）在轮廓的东部边缘下，在TWT的10-1 1秒内进行了深入的事件。Data在离线录音机上收集的Data还完成了折射/广阔的巨型collastal collust collistal curmision currision cormision inth the Offline Recorders。 A combined analysis of the seismic refection and refraction data indicates the following structural features in the surveyed area.(1) In the eastern part of the Hidaka Mountains, a material with a velocity of 5.8-6.0 km/s is almost outcr6pped.(2) The obtained velocity of 5.8-6.0 km/s is rather small as those of the middle crustal or lower crustal rocks which are expected to expose在希达卡山脉。这表明，浮雕的地壳岩石被高度变形并合并到周围的低速上层地壳材料中。获得的地震图像形成了与ARC-ARC碰撞相关的分层宽壁式结构的一部分。希达卡登山东部的反射器是库里尔弧向西覆盖的反光下地壳的上部。我们的结果为了解该地区发生的碰撞过程提供了重要的关键。