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North Atlantic, 37º - 40 º North
25º - 31 º West.
1600 km from Portuguese coast.
Here, can be find nine volcanic islands and several islets:
The Azores archipelago.
The archipelago is located above
an active Triple Junction.
This peculiar region,
where both volcanism as seismicity often occurs,
gives up the meeting of three, of around fifteen tectonic plates,
is the boundary of three tectonic plates meet, which divide the surface layer of earth:
the North American Plate, the Eurasian Plate
and the African Plate.
This area has several tectonic structures,
and it´s dynamics is related with the large seismic and volcanic activity
which frequently occur in archipelago.
Thus, the Mid-Atlantic Ridge,
seismically active,
is a divergent plate boundary.
Coming from the north and heading to the south
she crosses the Azores Plateau, and separates the American Plate
from the remaining Plates.
The Mid-Atlantic Ridge is a mid-ocean ridge
where the plates are moving away from each other
as a result of the injection of magmatic material, in its axial zone.
This way, new terrestrial crust is formed...
the seafloor spreading!
Another divergent structure that we can find here
is called the
Terceira Rift.
With direction northwest - southeast
and therefore oblique to the Mid-Atlantic Ridge,
the Rift is characterized by a intense seismic and volcanic activity.
Not only presents several alignments, but it´s also formed by a series
of ocean basins, ridges
and seamounts.
Further south of the archipelago,
another structure appears.
With a general direction from East to West,
is the East Azores Fracture Zone.
It extends to the East and contacts with Gloria Fault
which separate
the Eurasian from the African plate .
In the Azores region
there are no unique tectonic structures, or not sufficiently
continuous, that allow a precise definition of
the boundary between the African and the Eurasian Plates .
Instead, there seems to be
a large triangular shape,
where the tensions generated between the plates somehow accommodated,
creating a micro-plate, named the Azores Plateau.
The Azorean islands, are the emerged part of this platform.
A triangular submarine relief
with about 2000 meters depth