Three-Dimensional Joint Inversion Of Gravity,Magnetic Data And Magnetotelluric

Geophysical methods can be divided into gravity,magnetic,electrical,seismic,radiation,logging and geothermal.Each method only single underground abnormal object property inverse inference is made,with great limitations.Joint inversion based on petrophysical structural coupling of multiple or properties of geologic body of some kind of prior relationship inversion of geophysical observation data of geologicalgeophysical model of unity.Broke from a single joint inversion study on the anomalous in terms of physical properties,not only to overcome the limitations of a single physical inversion,and suppress the regular retrieval of multiplicity,are the future direction for the development of geophysics.Draw in in recent years mainly on the joint inversion of geophysical methods and research,In order to reduce the uncertainty of a single geophysical method of inversion and the influence of noise,this paper around the gravity,magnetic data and magnetotelluric to carry out the research of three-dimensional joint inversion.Inversion of gravity and magnetic process using depth weighted factors helped offset field attenuation of the signal,and uses a logarithmic-barrier method to prevent the inversion of magnetic susceptibility is negative phenomenon in the process.Magnetotelluric use limited-memory Broyden-Fletcher-Goldfarb-Shanno(L-BFGS)inversion algorithm,introducing the cross gradient function to achieve the physical structure of three kinds of mutual coupling,and finally developed a gravity,magnetic data and magnetoelectric three-dimensional joint inversion algorithm,and using the MPI method speed up the calculation.Through the theoretical model,the accuracy of the algorithm is proved by an example,the results show that both single prism model and combination prism model,the joint inversion results compared with the single inversion for anomalous body space form and has a good property value increases.Single prism model example makes anomalous body physical parameters(density,magnetic susceptibility and resistivity)are closer to the real physical parameters.Combination prism model of joint inversion results not only eliminates the false anomaly of physical parameters of surrounding rock,but also enhance the recovery degree of anomalous body boundary structure.