Isopors

Isopors

 

the isograms of secular variations in the components of terrestrial magnetism.

Isopors are concentrated around certain foci of secular movement, where the variations reach maximum values of ~0.16 amperes per m(~2 X 10 -3 oersted). The foci of secular movement are continuously shifting (up to 0.2 degrees per year) and changing in value. Accordingly, the entire isopor aggregate changes with time.