and the calculated anomalies are the result of a total magnetization 
(induced plus remanent) in the same direction as the present ia weaes 
field.: The computed and observed total intensity anomalies agree 
very well, and the computed H, and Za exhibit the same general char- 
acteristics of the "observed" components, except for a slight dis-_ 
placement to the south. In order to match amplitudes, an apparent 
susceptibility ( ) of 0.016cgs or its equivalent of 0.0086 cgs 
Kapp 
units in apparent magnetization was required. This relatively large 
value is explained in terms of a large component of remanent magneti- 
zation acting together with the induced magnetization. Although the 
solution of figure 9 is not unique, the model is reasonable and 
indicates that there is little sedimentary cover over the volcanics. 
Using another approach, intensity of magnetization calcula- 
‘tions were made for Kelvin with the three-dimensional technique of 
Vacquier (1962). Computations were made using both airborne and 
shipboard duuraa data, and the results (Van Yoorhis and Walczak, 
1963) indicate an intensity of magnetization of 0.01 cgs units, with 
a large component of remanence in a direction different from the 
present inducing field. 
It is likely that the other seamounts of Zone 1 are magnetized 
to this order of magnitude. A hand method (Rikitake, 1952) which 
represents the volcanoes as right circular cones, was used to obtain 
rough approximations of the magnetization of Bear, Physalia, Retriever, 
