Premium
THE EFFECT OF A SUPERPARAMAGNETIC LAYER ON THE TRANSIENT ELECTROMAGNETIC RESPONSE OF A GROUND *
Author(s) -
LEE T.
Publication year - 1984
Publication title -
geophysical prospecting
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.735
H-Index - 79
eISSN - 1365-2478
pISSN - 0016-8025
DOI - 10.1111/j.1365-2478.1984.tb01111.x
Subject(s) - superparamagnetism , transient (computer programming) , layer (electronics) , transient response , materials science , condensed matter physics , physics , nanotechnology , electrical engineering , magnetic field , magnetization , engineering , quantum mechanics , computer science , operating system
A bstract A thin superparamagnetic layer on the earth's surface greatly affects the transient electromagnetic response of a conducting ground. The effect of the layer is most evident for singleloop transient electromagnetic data where transient voltages decay as 1/ t . Even when a separate transmitter and receiver are used, the effect of the superparamagnetic layer is still pronounced. In this case the effect of the 1/ t term in the equation is much less. More dominant now is a 1/ t 2 term. The effect of the superparamagnetism can readily be seen in the analytical expressions for the apparent resistivities. If the presence of the superparamagnetic layer is not recognized, then the apparent resistivities decrease with time rather than approach the true value of the host rock.