The determination of density interface using the normalized total gravity gradient method
Wang Jialin;Wang Yixin;Wan Minghao;Shen Yi
It has been proved that normalized total gravity gradient method can be effectively used to ascertain the existence and exact location of single (or several) nonuniform density body. However, people have few experience in using it to determine density interface. On the ba- sis of a series of modeling experiments, in the paper the authors put forward the extreme point classification criterion which is different from that of Soviet expert E. C. Есисеева, explain the possibility and the necessity of using minimum value point, and expound how the characteristic of normalized total gravity gradient field is affected by profile length, sampling interval, harmonic number, and the eli- mination of background field. Modeling experiments show that the normalized total gravity gradient method is useful to the determination of fault, nonuniform density body and undulate density interface.. Model and actual example show that this is a quite good method for interpreting density interface qualitatively and semi-quantitatively.