The Periadriatic Seam (or fault) is a distinct

geologic fault In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tectonic ...

Southern Europe Southern Europe is also known as Mediterranean Europe, as its geography is marked by the Mediterranean Sea. Definitions of southern Europe include some or all of these countries and regions: Albania, Andorra, Bosnia and Herzegovina, Bulgaria, C ...

, running ''S-shaped'' about from the

Tyrrhenian Sea The Tyrrhenian Sea (, ; or ) , , , , is part of the Mediterranean Sea off the western coast of Italy. It is named for the Tyrrhenians, Tyrrhenian people identified with the Etruscans of Italy. Geography The sea is bounded by the islands of C ...

through the whole

Southern Alps The Southern Alps (; officially Southern Alps / Kā Tiritiri o te Moana) are a mountain range extending along much of the length of New Zealand, New Zealand's South Island, reaching its greatest elevations near the range's western side. The n ...

as far as

Hungary Hungary is a landlocked country in Central Europe. Spanning much of the Pannonian Basin, Carpathian Basin, it is bordered by Slovakia to the north, Ukraine to the northeast, Romania to the east and southeast, Serbia to the south, Croatia and ...

. It forms the division between the

Adriatic plate The Adriatic or Apulian plate is a small list of tectonic plates, tectonic plate carrying primarily continental crust that broke away from the African plate along a large transform fault in the Cretaceous period. The name Adriatic plate is usu ...

and the Eurasian plate.

Tectonics and geology

Within the

Eastern Alps The Eastern Alps are usually defined as the area east of a line from Lake Constance and the Alpine Rhine valley, up to the Splügen Pass at the Main chain of the Alps, Alpine divide, and down the Liro (Como), Liro River to Lake Como in the south. ...

, the line marks the border between the

Central Eastern Alps The Central Eastern Alps (), also referred to as Austrian Central Alps () or just Central Alps, comprise the main chain of the Eastern Alps in Austria and the adjacent regions of Switzerland, Liechtenstein, Italy and Slovenia. South of them is ...

and the

Southern Limestone Alps The Southern Limestone Alps (, ), also called the Southern Calcareous Alps, are the mountain range, ranges of the Eastern Alps south of the Central Eastern Alps mainly located in northern Italy and the adjacent lands of Austria and Slovenia. The ...

. In the

Western Alps The Western Alps are the western part of the Alps, Alpine Range including the southeastern part of France (e.g. Savoie), the whole of Monaco, the northwestern part of Italy (i.e. Piedmont and the Aosta Valley) and the southwestern part of Switzer ...

it forms the division between the southern Apulian foreland and the central

crystalline A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macrosc ...

zones of the Alps.

Continental collision In geology, continental collision is a phenomenon of plate tectonics that occurs at Convergent boundary, convergent boundaries. Continental collision is a variation on the fundamental process of subduction, whereby the subduction zone is destroy ...

is still going on, with the Apulian and Eurasian plates still converging. The central zones of the Alps are rising too, causing vertical slip along the fault. The result is the set of major fault zones collectively named Periadriatic Seam. Movement along the Periadriatic Seam is the cause for the

earthquake An earthquakealso called a quake, tremor, or tembloris the shaking of the Earth's surface resulting from a sudden release of energy in the lithosphere that creates seismic waves. Earthquakes can range in intensity, from those so weak they ...

zone between

Vienna Vienna ( ; ; ) is the capital city, capital, List of largest cities in Austria, most populous city, and one of Federal states of Austria, nine federal states of Austria. It is Austria's primate city, with just over two million inhabitants. ...

and

Friuli Friuli (; ; or ; ; ) is a historical region of northeast Italy. The region is marked by its separate regional and ethnic identity predominantly tied to the Friulians, who speak the Friulian language. It comprises the major part of the autono ...

. The last destructive earthquake happened in

in 1976. The uplift caused violent

erosion Erosion is the action of surface processes (such as Surface runoff, water flow or wind) that removes soil, Rock (geology), rock, or dissolved material from one location on the Earth's crust#Crust, Earth's crust and then sediment transport, tran ...

of the young orogen, which led to the formation of the

Hohe Tauern The High Tauern ( pl.; , ) are a mountain range on the main chain of the Central Eastern Alps, comprising the highest peaks east of the Brenner Pass. The crest forms the southern border of the Austrian states of Salzburg, Carinthia and East Tyr ...

window A window is an opening in a wall, door, roof, or vehicle that allows the exchange of light and may also allow the passage of sound and sometimes air. Modern windows are usually glazed or covered in some other transparent or translucent ma ...

. At several regions a 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'':

Pannonian Basin The Pannonian Basin, with the term Carpathian Basin being sometimes preferred in Hungarian literature, is a large sedimentary basin situated in southeastern Central Europe. After the Treaty of Trianon following World War I, the geomorpholog ...

–

Pohorje Pohorje (), also known as the Pohorje Massif or the Pohorje Mountains (, ''Bacherngebirge'' or often simply ''Bachern''), is a mostly wooded, medium-high mountain range south of the Drava River in northeastern Slovenia. According to the traditio ...

–

Karawanks The Karawanks or Karavankas or Karavanks (; , ) are a mountain range of the Southern Limestone Alps on the border between Slovenia to the south and Austria to the north. With a total length of in an east–west direction, the Karawanks chain is o ...

–

Drau The Drava or Drave (, ; ; ; ; ), historically known as the Dravis or Dravus, is a river in southern Central Europe.

valley (''Jauntal, Rosental'') –

Rosegg Rosegg () is a town in the district of Villach-Land in Carinthia in Austria Austria, formally the Republic of Austria, is a landlocked country in Central Europe, lying in the Eastern Alps. It is a federation of nine Federal states of Aust ...

*''Gailtal line'':

Villach Villach (; ; ; ) is the seventh-largest city in Austria and the second-largest in the federal state of Carinthia. It is an important traffic junction for southern Austria and the whole Alpe-Adria region. , the population is 61,887. Together wit ...

–

Gail Gail may refer to: People * Gail (given name), list of notable people with the given name Surname * Jean-Baptiste Gail (1755–1829), French Hellenist scholar * Max Gail (born 1943), American actor * Sophie Gail (1775–1819), French singer ...

valley – Kartitsch *''Pustertal line'': Sillian –

Puster Valley The Puster Valley ( ; , ) is one of the largest longitudinal valleys in the Alps that runs in an east-west direction between Lienz in East Tyrol, Austria, and Mühlbach near Brixen in South Tyrol, Italy. The South Tyrolean municipalities of th ...

–

Bruneck Bruneck (; or Ladin language, Ladin: ''Bornech'' or ''Burnech''; or ''Brunopolis'') is the largest town in the Puster Valley in the Italy, Italian province of South Tyrol. Geography Bruneck rises up in the middle of a wide valley (perhaps a ...

*'' Giudicárie line'':

Meran Merano (, ; ) or Meran () is a (municipality) in South Tyrol, Northern Italy. Generally best known for its spa resorts, it is located within a basin, surrounded by mountains standing up to above sea level, at the entrance to the Passeier Va ...

– Val di Sole *''Insubric line'':

Tonale Pass Tonale Pass () (el. 1883 m./6178 ft.) is a high mountain pass in northern Italy across the Rhaetian Alps, between Lombardy and Trentino. It connects Valcamonica and Val di Sole. It is delimited by the Ortler Alps to the nort ...

–

Val Camonica Val Camonica or Valcamonica (), also Valle Camonica and anglicized as Camonica Valley, is one of the largest valleys of the central Alps, in eastern Lombardy, Italy. It extends about from the Tonale Pass to Corna Trentapassi, in the c ...

–

Valtellina Valtellina or the Valtelline (occasionally spelled as two words in English: Val Telline; (); or ; ; ) is a valley in the Lombardy region of northern Italy, bordering Switzerland. Today it is known for its ski centre, hot spring spas, bresa ...

– Piano di Magadino – Ivrea zone. It is composed of the east–west running Tonale line to the east and the curved Canavese line, which follows the Western Alps inner arc, to the west. The two lines meet near

Locarno Locarno (; ; Ticinese dialect, Ticinese: ; formerly in ) is a southern Switzerland, Swiss List of towns in Switzerland, town and Municipalities of Switzerland, municipality in the district Locarno (district), Locarno (of which it is the capita ...

in the canton of

Ticino Ticino ( ), sometimes Tessin (), officially the Republic and Canton of Ticino or less formally the Canton of Ticino, is one of the Canton of Switzerland, 26 cantons forming the Switzerland, Swiss Confederation. It is composed of eight districts ...

Switzerland Switzerland, officially the Swiss Confederation, is a landlocked country located in west-central Europe. It is bordered by Italy to the south, France to the west, Germany to the north, and Austria and Liechtenstein to the east. Switzerland ...

. The Cavanese line is forms the NNE-SSW striking boundary between the Ivrea Zone (

) and Sesia zone (Central Alps) and together with the Ivrea Zone, geometrically it forms backbone of the inner arc of the Western Alps.Schmid (2017)

References

*Schmid S.M. (2017
On the Insubric line and the Southern Steep Belt of the Penninic nappes in the Ticino area
(including 2 excursion guides) Swiss Bulletin of Geology, Vol. 22 (2) pp. 69–89 {{Authority control Geology of the Alps Regional geology Geology of Austria Geology of Hungary Geology of Italy Geology of Slovenia Geology of Switzerland Central Alps Southern Limestone Alps Suture zones

Tectonics and geology

Geographic position and names

See also

References