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Study on subsurface structure by using geoidal height from GPS/leveling and gravity in the southern part of central Japan

利用 GPS 大地水准面高度/水准测量和重力研究日本中部南部的地下结构

基本信息

批准号：
06640543
负责人：
SATOMURA Mikio
金额：
$ 1.22万
依托单位：
Shizuoka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06640543/
关键词：
Geoid Gravity GPS Southern Parts of Central Japan Subsurface Structure Mt.Fuji Isostasy Akaishi Mountains 岩石密度

项目摘要

Determination of the geoid is one of the fundamental subjects of geodesy. Its study is necessary to combine traditional geodetic survey data and new geodetic data by applying space technique. Development of GPS technique makes precise determination of geoidal height possible by comparison between ellipsoidal height and orthometric height.It is thought that the collision of the Pilippine Sea plate to the Eurasia plate produced volcanoes such as Mt.Fuji and tectonic mountains such as Akaishi mountains in the southern part of central Japan. The subsurface structures of this region have been investigated through gravity surveys and seismic explorations. In this study they are investigated by adding geoid data to gravity and seismic exploration data.We performed precise determination of geoidal heights by GPS measurements near benchmarks, and the geoidal heights obtained at some stations in Akaishi mountains area have more than 1 m differences from those obtained from gravity data.We analyzed gravity data in the area concerned, and made clear that there is no subducting slab with high density to the northwest direction from Izu Peninsula. We also pointed out that the Moho discontinuity is deeper than that estimated from seismic explorations under Akaishi mountains.It was thought that Mt.Fuji has no isostatic root because the contour of Bouguer anomalies has no disturbances there. The gravity effects of the root, however, are so small that the root, if it exists, seldom affects to Bouguer anomalies. We made isostatic anomaly map and showed that gravity anomalies near Mt.Fuji can be explained in both cases that Mt.Fuji has an isostatic root and not.

大地水准面的确定是大地测量学的基本课题之一。它的研究需要将传统的大地测量数据与应用空间技术的新的大地测量数据相结合。GPS技术的发展使得通过比较椭球高和正高来精确确定大地水准面成为可能。人们认为，菲律宾海板块与欧亚板块的碰撞产生了富士山等火山和日本中部南部的构造山脉等构造山脉。通过重力测量和地震勘探，研究了该地区的地下构造。本研究通过在重力和地震勘探数据中加入大地水准面数据进行了研究。我们在基准附近通过GPS测量精确地确定了大地水准面高度，赤石山区一些台站的大地水准面高度与重力数据相差超过1m。我们分析了有关地区的重力数据，明确了从伊豆半岛向西北方向没有高密度的俯冲板。我们还指出，莫霍面的深度比赤石山下的地震勘探估计的要深，认为富士山不存在均衡根，因为布格异常的等高线在那里没有扰动。然而，根部的重力效应是如此之小，以至于根部即使存在，对布格异常的影响也很小。绘制了均衡异常图，表明富士山附近的重力异常可以解释为富士山有均衡根和没有均衡根两种情况。