摘要
采用径向成层的地球模型计算由月亮和太阳的潮汐位所产生的地球形变位。分析的基本出发点是牛顿万有引力位是由随时间变化的质量密度增量产生的;由质量守恒定律,质量密度增量来自未挠动的质量密度的散度和位移矢量场。对质量密度的径向成层模型,采用Dziewonski和Anderson的PREN地球模型(1981);对勒夫(Love)和志田(Shida)数,采用Varga和Denis的模型(1988);对月亮和太阳的潮汐位分别取至3和2阶。计算了地球的形变位。所得结果比用勒夫假定(即δW=K_L(γ)V_(?))计算的结果,相差20％。本文给出了详细的数字结果和讨论。
For a radially stratified non-rotating selfgravitating massive body like the earth we have computed the Lagrangean deformation potential of gravity generated by the tidal potential, namely of the moon and the sun. The analysis is based on the Newton incremental gravitational potential whose source is the time-varying incremental mass density. According to the law of mass conservation the incremental mass density can be inferred from the divergency of the scalar unperturbed mass density and the vectorial displacement field. For a model massive body of radially stratified density ρ(r), i. e. of PREM type, for a standard displacement field d (x,t)generated by Love-Shida kernel functions h_L(r) ,l_S(r)and a tidal potential of degree 2 and 3(moon) and 2(sun), the Lagrangean deformation potential varies in spacetime over about 25cm at geoid level. It is outlined that the Lagrangean deformation potential localizes only to the tidal potential at the evaluation point once the radial mass density ρ(r)has a discontinuity, i. e. at the earth surface of at some internal interfaces like the core-mantle and others. The Love kernel function K_L (r) restricts the Lagrangean deformation potential to the localization case; departures from the Love-Shida hypothesis of the order of 20% for the Lagrangean deformation potential are documented. Detailed numerical examples are given.
出处
《地壳形变与地震》
CSCD
1992年第3期1-12,共12页
Crustal Deformation and Earthquake
关键词
月亮
太阳
潮汐
地球
变位
Deformation Potential by the Tide, Time Variation of the Geoid
