STUDY ON THE TRANSIENT ELECTROMAGNETIC （TEM） SOUNDING WITH ELECTRIC DIPOLE.IV.APPARENT RESISTIVITY IN TEM SOUNDING

The numerical calculation method of apparent resistively in whole area(period) by vertical magnetic field H_z(t) of electric dipole is given,and the time range is expanded to tens seconds to satisfy the need for detecting larger depth by big offset distance(r).The results of analogy computation indicate that the apparent resistivity in whole area can clearly reflect the structure of geological section,contributing to the qualitative and quantitative interpretations.