Isostatic Gravity Anomaly And Its Geodynamic Characters In China And Its Adjacent Regions

The conception of crustal isostasy produces a great effect to the geo-scientific research; especially take an important role in the studies of Geodesy and Geodynamics. As one of important method for the research of seafloor topography, crustal tectonics and earthquake activity, isostatic gravity and geoid anomalies have been widely used by many scientists. Crustal isostatic model can best fit to the situation of density inhomogeneity of the earth. The main works in this paper are as follow:1. Isostatic gravity and geoid anomaly of China and its adjacent regionsBase on theory of lithosphere elastic flexure isostatic compensation, the spherical harmonic series expressions of topography-isostasy compensation gravity and geoid are established. Then we can research the relationship between topography-isostatsy compensation gravity and geoid and order and degree of spherical harmonic series, and discuss the characters of topography-isostatsy compensation gravity and geoid. Deducting topography-isostatsy compensation gravity and geoid anomalies from free air gravity anomaly and surveyed geoid anomaly, we can obtain isostatic gravity anomaly and isostatic geoid anomaly. Isostatic geoid anomaly has removed effect of shallow crust substance asymmetry, reflects substance distribution of deeper earth. Isostatic gravity anomaly shows the character of middle-short wavelength, reflects unbalance of crust and upper mantle and dynamical character of substance adjusting.2. Earth interior density distribution beneath China and its adjacent regionsEarth interior density is one of most important physical parameters of the earth. It is closely connected with earth shape, formation and evolvement, plate motion, crustal isostatic adjust and geodynamics. The density research can be divided into two parts of earth normal density distribution and density anomaly. The research methods are different between study of normal density distribution and density anomaly.The normal earth density distribution should let earth total mass, angular momentum ,ellipticity,earth radius and earth surface gravity potential fulfil the results of space geodesy observation. Imposing the newest density results detected by geophysical methods to revise PREM earth density model, and adjusting ellipticity of every tectonic sphere of earth interior, we can attain a new earth...