The 'Periadriatic Seam' is a distinct
geologic fault in Southern Europe, running ''S-shaped'' about 1000 km from the
Tyrrhenian Sea through the whole
Southern Alps as far as
Hungary. It forms the division between the
Adriatic plate and the
European plate. The term 'Insubric line' is sometimes used to address the whole Periadriatic Seam, but it is more commonly used to mean just a western part of it.

Relief of the Alps, and the Periadriatic Seam
Tectonics and geology
Within the
Eastern Alps, the line marks the border between the
Central Eastern Alps and the
Southern Limestone Alps. In the
Western Alps it forms the division between the southern Apulian
foreland and the central
crystalline zones of the Alps.
Continental collision is still going on, with the Apulian and European plates still
converging. Movement along the Periadriatic Seam is the cause for the
earthquake zone between
Vienna and
Friuli. Meanwhile, the central zones of the Alps are rising too, causing
vertical slip along the fault. The result is the set of major
faultzones collectively named Periadriatic Seam. The uplift caused violent
erosion of the young orogen, which led to the formation of the
Hohe Tauern window. At several regions an heavy
uplift of the Central Alps by some kilometers took place, and also a shift of more than 50 km.
Geographic position and names
From east to west, the course of the Periadriatic Seam and the names given to it regionally are as follows:
★ ''Drau line'': Southwestern Hungary -
Styria -
Drau valley (Jaun-, Rosental) -
Klagenfurt)
★ ''Gailtal line'':
Gailtal
★ ''Pustertal line'':
Pustertal-Val Pusteria -
Bruneck-Brunico -
Merano
★ ''
Giudicárie line'':
Merano -
Val di Sole
★ ''Tonale'' or ''Insubric line'':
Tonale Pass -
Val Camonica -
Veltlin -
Biella -
Gulf of Genoa.
See also
★
Apulian plate