The actual position of Portugal is the result of a process lasted million of years and it is presently developing. 200 millions years ago all the emerged lands were joined together in one heap called Pangea that included all the actual continents. 135 millions years ago there was the first division in two heaps: Laurasia at north and Gandwana at south.

Today the emerged lands are divided in by seas, as we can see, and they found the five continents, but by the features of America, Europe and Asia we can understand that once all these lands were together. Division's process is not finished and maybe in 50 millions years the land will be further on divided. This result had been studied by the rocks. One important feature of the Earth is that the way the continents are grouped together makes possible the presence of ice at the poles, in the same moment; this feature makes Earth subject to glacial periods, that happened in the past and may happen in the future. One proof that once the continents were together in the Pangea is in the fossils; in fact in the south of America, India, Australia and Africa has been found fossils of the same animals and plants. One example of the movement of the emerged lands is the opening of the gulf of Biscaglia caused by the rotation Towards east of the Iberian peninsula. During the Inferior and Middle Jurassic we can see that a first rotation caused the opening of this gulf, that continued in the Inferior Cretaceous. At the end of Superior Cretaceous the opening of the gulf was finished, the peninsula assumed the actual position, the frontiers of the Iberian plate were already passive and Alpine orogeny started.

Portugal is with Spain in a small plate and is neat to the frontier between this plate and the Atlantic Ocean plate. The rift between the two plates is near Azzorre and continues now to widen out, while the European and African plates continues to collide near Madeira's archipelago. The process, started in Cretaceous, has brought the Iberian peninsula to depart from the American continent until tie up with European continent at the beginning of Ercinic orogeny.

The seismic activity is tightly associated with the configuration of the Earth crust and with plates' movements. The distribution of the volcanoes generally coincides with the seismic areas that now are shared in three groups: the zone of the oceanic ridges, where the plates depart and new crust is formed; The zone of collision among plates where crust is destroyed; at last the zone of volcanism in the inside of plates called "hot spots".

In Portugal there is not a strong seismic activity; Azzorre's archipelago is the zone with the most intense activity, it is inside one of the main seismic zones of the globe. This archipelago is in an area where the seismic Atlantic zone and the prolongation of the Mediterranean one meet together; in fact in this zone there are three tectonic plates, the American one, the African one and the European-Asiatic one in an area called "Triple point" where there are intense forces that cause instability. This is an area of uneven topography. Instead the Madeira's archipelago how a very low seismic activity.

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