On: “Results of a controlled‐source audiofrequency magnetotelluric survey at the Puhimau thermal area, Kilauea Volcano, Hawaii” by L. C. Bartel and R. D. Jacobson (GEOPHYSICS, 52, 665–677, May 1987).

Abstract

Bartel and Jacobson try to correct apparent resistivity values from CSAMT measurements, where the plane‐wave approximation is not valid. They want to convert CSAMT curves to passive MT curves (Cagniard curves), which can be interpreted by 2-D modeling. The measured CSAMT [Formula: see text] value is projected onto the [Formula: see text] axis in parallel with the half‐space curves of a horizontal electrical dipole in the given distance between receiver and transmitter. The example looks convincing, and it may be supposed to be a simple near‐field correction.