| Project/Area Number |
06640543
|
|---|
| Research Category |
Grant-in-Aid for General Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
固体地球物理学
|
|---|
| Research Institution | Shizuoka University |
|---|
Principal Investigator |
SATOMURA Mikio Shizuoka University, Faculty of Science, Professor, 理学部, 教授 (50126778)
|
|---|
| Project Period (FY) |
1994 – 1995
|
| Project Status |
Completed (Fiscal Year 1995)
|
| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1995: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1994: ¥1,400,000 (Direct Cost: ¥1,400,000)
|
|---|
| Keywords | Geoid / Gravity / GPS / Southern Parts of Central Japan / Subsurface Structure / Mt.Fuji / Isostasy / Akaishi Mountains / 岩石密度 |
|---|
| Research Abstract |
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.
|
