2002 Fiscal Year Final Research Report Summary
Construction of Plate-Dynamic Model
| Project/Area Number |
12440122
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
固体地球物理学
|
|---|
| Research Institution | The University of Tokyo (2002)
Hiroshima University (2000-2001) |
|---|
Principal Investigator |
HONDA Satoru Earthquake Research Institute, professor, 地震研究所, 教授 (00219239)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
IWASE Yasuyuki Department of Applied Science, National Defense Academy, Research Associate, 応用科学群, 助手 (40294516)
NAKAKUKI Tomoeki Graduate School of Science, Hiroshima University, Research Associate, 大学院・理学研究科, 助手 (10263667)
SENO Tetsuzo Earthquake Research Institute, professor, 地震研究所, 教授 (10216567)
|
|---|
| Project Period (FY) |
2000 – 2002
|
| Keywords | Plate Tectonics / Mantle Convection / Numerical Simulation |
|---|
| Research Abstract |
1. In 2D mantle convection models, we took into account the rheology which is affected by the past history of yielding, and we tried to construct a model which shows a plate-like behavior. Based on this model, we constructed a model which shows a one-sided subduction. We stressed that the rheological asymmetry is much more important than the asymmetry of other physical properties in constructing a one-sided subduction.
2. Using above modet, we estimated the contribution of ridge push for the initiation of subduction.
3. We constructed a fundamental 3D-spherical model which shoes a present plate motions. In our model, we introduced a low viscosity in plate boundary area to achieve a plate-like movement. By reducing the viscosity at the plate boundaries, systematically, we found that the movement becomes similar to the plate-like one. However, the magnitude and direction of plate movements are different. This implies that we need to know the detail of load distribution and rheology of plat
… More
e boundaries.
4. In 3D-spherical model, we tried to understand the thermal-coupling between the conductive thick continental lithosphere and the underlying mantle. Although we could not include the complete mechanical coupling, we could confirm that the continental break-up and its aggregation.
5. To understand the along-arc variation of thermal structure as revealed by the distribution of volcanoes, we constructed a simple 3-D model of subduction zone and found the existence of small-scale convection, which shows a roll-like structure. We tried to constrain the condition of occurrence of such small-convections.
6. At the plate boundaries, the fracture process is the most important one and it may affect the plate motions. To understand this, we conducted the numerical simulation of fracture using DEM (Discrete Element Method). In our study, we check the effects of rotation between each element and pointed out its importance.
7. To understand the thermal evolution of the Earth, we adopted the parameterized convection mode which takes into account the initiation of plate tectonics. We tried to constrain the period when the plate tectonics started. Less
|
