Bardarbunga is a large central volcano containing a large caldera (60 kmē), which is close to 700 m deep.  In 1973 a satellite picture revealed vaguely the shape of the caldera and a consequent research confirmed the contours of the landscape under the ice shield.  Earthquakes are frequent in the area.  The volcanic history of the central volcano is still unknown, but a few eruptions in its vicinity during Holocene and historical times are known.

In 1972 a 415 m long ice core showed about 30 layers of tephra from the middle of the 17^th century up to that date and further research is going to reduce the number of the secrets of this volcanic system.

Vatnajokull