Optimum choice of parameters and numerical schemes for a regional gravimetric Moho recovery

作者：Samurdhika Rathnayake,Robert Tenzer

摘要：Despite practical limitations of isostatic theories to model the Moho geometry are well-known,gravimetric methods are often used in terrestrial studies of crustal structure in regions with a low seismic data coverage.Moreover,these methods are indispensable in planetary studies.Various gravimetric methods have been proposed.The Airy and Pratt theories are defined based on adopting a local compensation mechanism.The Vening Meinesz theory assumes a regional isostatic flexural model.The Vening Meinesz regional isostatic model generally describes a respond of the lithosphere to a load more realistically than the Airy model over continents.The Pratt method,on the other hand,better describes a compensation mechanism of the oceanic lithosphere.The application of a particular isostatic model also depends on applied numerical procedures,parameters for inversion,input data specifications,and many other aspects.In this study,we address some basic aspects by applying local and regional isostatic models for a Moho recovery.We also conduct a spectral analysis to assess a spectral resolution of gravity data that is optimal for a Moho recovery.Furthermore,we inspect the influence of low-degree spherical harmonics of gravity field on a Moho geometry.Gravimetric results are validated using seismic data at the European plate.Our results confirm a better performance of a regional compensation principle.We also demonstrate that a different thickness of the oceanic and continental crustal thickness should be taken into account as a priori information.Spectral analysis indicates that gravity data used for a Moho inversion should optimally have a spatial resolution between degrees 60 to 180.Results also show that low-degree spherical harmonics do not modify significantly the Moho geometry,particularly over regions with a relatively homogenous structure of deep mantle.

发文机构：Department of Land Surveying and Geo-Informatics

关键词：CRUSTGRAVITYMOHOINVERSIONISOSTASY

分类号： P631.44[天文地球—地质矿产勘探][天文地球—地质学]