GRAVITY ISOSTASY AND MASS ISOSTASY
Yang Xuexiang;Chen Dianyou(Changchun Univ. of Earth Sciences.Changchun 130026)
Isostasy theory is playing more and more important roles in the rpsearchof geodesy and sea level changes,But the traditional isostasy models can no longer satisfythe needs of precision in recent practice. Both Pratt′s and Airy′s models are based on aplane crust and the vertical variation of gravity is not taking into account.So thesemodels are in fact the isostasies of mass. If we consider the isostasv models based on aspherical crust and take into account the vertical variation of gravity,the isostasy modelsthen become isostasy of gravity.Numerical estimations show that the differences betweenthe isostasy models of mass and gravity are not negligable,These differences would playimportant roles in the research Of stress state in the crust.