点位错引起的单层密度变化

采用求解地壳单层密度变化的一般公式，导出其平面近似公式并给出了相应的数值计算方法。在此基础上，将点位错引起的地表形变和重力变化同时解析延拓至Ｂｊｅｒｈａｍｍａｒ球面上，得到了点位错引起的地壳单层密度变化的图像。分析表明：①单层密度变化图像与地表形变、重力变化图像相似；②地表形变对单层密度变化的影响比地表重力变化要大；③若点位错引起地表重力变化为１０－６～１０－７ｍ／ｓ２量级、高程变化为０．１～１ｍ量级，则单层密度变化可达１０３～１０４ｋｇ／ｍ２量级；④单层密度变化在隆升区为正，沉降区为负

SINGLE-LAYER DENSITY CHANGES CAUSED BY POINT DISLOCATIONS

By use of the common formula for solving the time variations of the crustal density, the approximative plane formula is derived and its numerical calculation method is given. Accordingly, the surface deformation and gravity changes caused by point dislocations are analyzed and continuated to the Bjerhammar shpere,then the graph of single-layer density changes raised by point dislocations is calculated.The result shows:(1)The graph of single-layer density changes is similar to the surface deformation and gravity changes,(2)The effect of surface deformations on the single-layer density changes is larger than the surface gravity changes,(3)If the surface gravity changes caused by point dislocation are the level of 10 -6 or 10 -7 m/s 2 and the surface topographic changes are the level of 0.1 or 1.0m,the single-layer density changes will reach the level of 10 3 or 10 4kg/m 2,(4)the single-layer density changes are positive on the uplife area and negative on the subsidence area.