Schmucker-Weidelt Lecture Notes, Aarhus, 1975 - MTNet

E~~ T r: j = const. or E T + E a r = j = 0.
n~ a a
This approach has been used by HAACK to obtain a fairly reliable
conductance cross-section through the Rhinegraben.
In the case of E-pol-arisation a different kind of simplification
may be in order: Suppose tHe half-width of the anomaly is
sufficiently small in comparison to (W~~T)-' everwhere. Then no
significant local self-induction clue to HaZ which produces
takes places, i.e. the electric field driving the anomalous
current will be the large-scale induced normal field only:
Assuming E again to be known, the conductance anomaly is now
-n ll
derived from the observation of the tangential magnetic var,iation
anomaly normal to the trend,
In the actual performance with real data all field components
may be expressed in terms of their transfer functions W and Z
and thus be norrnalised with regard to h+
r1tg'
Let T be variable only in one horizontal direction, say, i.n y-
dlrec-tion'which. implies that the anomal.ous fj-eld is also variable
only in that direction, obeying the field equa-tions
CE-polarisation) (H-polarisation)
-
H+ - 1-1- = H - H.k -
ay ay ?ax ax ax - jay
with
and