| Project/Area Number |
17403006
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 海外学術 |
|---|
| Research Field |
Solid earth and planetary physics
|
|---|
| Research Institution | The University of Tokyo |
|---|
Principal Investigator |
IIDAKA Takashi The University of Tokyo, Earthquake Research Institute, Associate Professor (00221747)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
IWAMORI Hikaru The University of Tokyo, Graduate School of Science, Associate Professor (80221795)
HIRATA Naoshi The University of Tokyo, Earthquake Research Institute, Professor (90156670)
|
|---|
| Project Period (FY) |
2005 – 2007
|
| Project Status |
Completed (Fiscal Year 2007)
|
| Budget Amount *help |
¥10,690,000 (Direct Cost: ¥10,000,000、Indirect Cost: ¥690,000)
Fiscal Year 2007: ¥2,990,000 (Direct Cost: ¥2,300,000、Indirect Cost: ¥690,000)
Fiscal Year 2006: ¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 2005: ¥4,300,000 (Direct Cost: ¥4,300,000)
|
|---|
| Keywords | Subduction zone / Seismicity / Ridge / Triple junction / Chili trench / liquid / Low velocity zone |
|---|
| Research Abstract |
We deployed seismic observation at the area with the latitude of 44 S-49 S and longitude of 74W-71W. The 60 seismometers were set up at the area for two years. We use the methods of seismic tomography, surface wave analysis, and receiver function analysis. Seismic tomographic studies with P- and S- waves revealed the seismic structure at the area. The seismic structure changes from north to south along the latitude. In the northern part of the research area, the slab is subducting with dip angles of 10-20 deg. In this area, the old plate is descending beneath the other plate. At the eastern part of the area, the dip angle of the slab increase sharply. The large lateral variation of the dip angles of the subducting slab was found. At the area with steep dip angle of the slab, the dip angle of the slab is estimated to be 30 - 45 deg. The bend of the slab observed at the wide area. The region that the ridge is subducting shows a characteristic structure. The low velocity zone was detected below the slab. The ridge subducting area is also characterized to be low velocity. The velocity of the area was estimated to be 10 % lower than normal mantle velocity It is considered that the hot mantle rise up to the shallower part.
The petrology studies considering thermal structure reveal a fine image of the subduction zone that the high temperature ridge is descending region.
|
