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Study of a Crater Structure found in the south of Takamatsu City, Kagawa Prefecture, Japan Professor

日本香川县高松市南部发现的陨石坑结构研究教授

基本信息

批准号：
04452063
负责人：
KONO Yoshiteru
金额：
$ 4.93万
依托单位：
Kanazawa University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1992
资助国家：
日本
起止时间：
1992 至 1994
项目状态：
已结题

项目摘要

A crater-like structure was found in the south of Takamatsu city, Kagawa prefecture, western Japan. This may be the first finding of an impact crater in Japan.The structure was firstly detected by a abnormal value of gravity which is obtained in a course of regional gravity measurements over the Japanese Islands by us. After several tens of gravity measurements around the anomalous data point, depression of gravity anomaly appeared clearly. This crater was named as the Takamatsu crater. Topography around the crater is nearly flat and no geographical manifestation to indicate a crater-like structure beneath the earth's surface.More than 500 gravity measurements, geomagnetic anomaly measurements at more than 100 points and 2 sections of reflecting seismic wave measurements were carried out over and around the crater.Gravity and seismological analysis revealed that the crater is 4 km in diameter and 1.5 km in depth. The structure presumably buried by about 100 m thick Quaternary sediments.There are two hypothesis about origin of the Takamatsu crater. One is meteorite impact origin, i.e., impact crater. The other is volcanic eruption origin, i.e., caldera.Already some characteristic minerals are found from the crater area suggesting meteoritic impact origin.This crater also contains great amount of underground water. Since the crater has not only scientific values but also economical values, we hope that deep drillings undertaken in this crater.

在日本西部香川县高松市南部发现了一个类似火山口的结构。这可能是日本第一次发现撞击坑。我们在日本群岛上空进行区域重力测量时，首先通过重力值异常探测到了这一构造。在异常数据点周围进行了几十次重力测量后，重力异常凹陷明显。这个陨石坑被命名为高松陨石坑。陨石坑周围的地形几乎是平坦的，没有显示出地表下有类似火山口的结构。在陨石坑及其周围进行了500多个重力点的地磁异常测量和2个反射地震波的测量。重力和地震分析表明，陨石坑直径4公里，深度1.5公里。该构造可能被大约100米厚的第四纪沉积物所掩埋。关于高松陨石坑的起源有两种假说。一种是陨石撞击的起源，即撞击坑。另一种是火山喷发成因，即火山口。在陨石坑地区已经发现了一些特征矿物，表明是陨石撞击的来源。这个陨石坑还含有大量的地下水。由于陨石坑不仅具有科学价值，而且具有经济价值，我们希望在这个陨石坑进行深井钻探。