60
over larger areas. Such events were detected over
the southern region of the Atlantic Ocean where
the operation of Hubble space telescope was regularly disturbed due to the decreased protection
of the weakening magnetic field. The magnetic
field is still decreasing currently in this region.
Some scientists believe that this decrease will
extend over larger areas and eventually a pole
reversal will take place. This could be a long process regarding human time span, but it is a disadvantageous process for humans due to the
important social role of electronics and telecommunication. This reversal is presumed to be also
harmful to the biosphere (disturbing, for example, the orientation of migrating birds); however,
our knowledge in this field needs improvement.
For the time being, humans cannot interfere
this process; therefore, we have to accommodate
to the changes. Currently there are no fully
worked out methods for such accommodation
yet. The protection of Hubble telescope for
example was solved by changing its orbit around
the Earth. In case the decreasing magnetic field
extends over greater areas such solutions will not
be enough.
3.2
Effects of Material Flows
in the Mantle
and the Lithosphere
on the Society
In Fig. 2.16 (Chap. 2) presenting the new geodynamic model the huge cycle of currents in the
mantle can be seen clearly. Subduction of oceanic slabs into the mantle, occasionally down to
layer D″ at the depth of 2900 km is part of this
cycle. Primary mantle plumes rising from this
depth and crossing the crust cause volcanism on
the surface of Earth. The two mega-rises of mantle material (African and Pacific) are stuck at the
depth of 600 km and spread like a mushroom
head. Secondary mantle plumes transport molten
material from the core from this level to the surface. Volcanism induced by primary and secondary mantle plumes, however, gives only a fraction
of the active volcanoes on Earth. It is known
widely that most active volcanoes are related to
plate boundaries and most of the high energy
earthquakes occur in the same areas (Lowrie
2007). Both natural processes have significant
Fig. 3.1 Magnetic field
pattern of Earth
3 Internal Material Flows in the Earth and Their Effects on the Society
over larger areas. Such events were detected over
the southern region of the Atlantic Ocean where
the operation of Hubble space telescope was regularly disturbed due to the decreased protection
of the weakening magnetic field. The magnetic
field is still decreasing currently in this region.
Some scientists believe that this decrease will
extend over larger areas and eventually a pole
reversal will take place. This could be a long process regarding human time span, but it is a disadvantageous process for humans due to the
important social role of electronics and telecommunication. This reversal is presumed to be also
harmful to the biosphere (disturbing, for example, the orientation of migrating birds); however,
our knowledge in this field needs improvement.
For the time being, humans cannot interfere
this process; therefore, we have to accommodate
to the changes. Currently there are no fully
worked out methods for such accommodation
yet. The protection of Hubble telescope for
example was solved by changing its orbit around
the Earth. In case the decreasing magnetic field
extends over greater areas such solutions will not
be enough.
3.2
Effects of Material Flows
in the Mantle
and the Lithosphere
on the Society
In Fig. 2.16 (Chap. 2) presenting the new geodynamic model the huge cycle of currents in the
mantle can be seen clearly. Subduction of oceanic slabs into the mantle, occasionally down to
layer D″ at the depth of 2900 km is part of this
cycle. Primary mantle plumes rising from this
depth and crossing the crust cause volcanism on
the surface of Earth. The two mega-rises of mantle material (African and Pacific) are stuck at the
depth of 600 km and spread like a mushroom
head. Secondary mantle plumes transport molten
material from the core from this level to the surface. Volcanism induced by primary and secondary mantle plumes, however, gives only a fraction
of the active volcanoes on Earth. It is known
widely that most active volcanoes are related to
plate boundaries and most of the high energy
earthquakes occur in the same areas (Lowrie
2007). Both natural processes have significant
Fig. 3.1 Magnetic field
pattern of Earth
3 Internal Material Flows in the Earth and Their Effects on the Society