Geophysical and geological information indicate that the Adriatic Sea and the Po Valley are associated with a tectonic microplate — identified as the Apulian or Adriatic Plate — that separated from the African Plate during the Mesozoic era . This separation began in the Middle and Late Triassic , when limestone began to be deposited in the area . Between the Norian and Late Cretaceous , the Adriatic and Apulia Carbonate Platforms formed as a thick series of carbonate sediments ( dolomites and limestones ) , up to deep . Remnants of the former are found in the Adriatic Sea , as well as in the southern Alps and the Dinaric Alps , and remnants of the latter are seen as the Gargano Promontory and the Maiella mountain . In the Eocene and early Oligocene , the plate moved north and north-east , contributing to the Alpine orogeny ( along with the African and Eurasian Plates ' movements ) via the tectonic uplift of the Dinarides and Alps . In the Late Oligocene , the motion was reversed and the Apennine Mountains ' orogeny took place . An unbroken zone of increased seismic activity borders the Adriatic Sea , with a belt of thrust faults generally oriented in the northeast – southwest direction on the east coast and the northeast – southwest normal faults in the Apennines , indicating an Adriatic counterclockwise rotation . An active fault has been identified to the northwest of Dubrovnik , adding to the Dalmatian islands as the Eurasian Plate slides over the Adriatic microplate . Furthermore , the fault causes the Apennine peninsula 's southern tip to move towards the opposite shore by about per year . If this movement continues , the seafloor will be completely consumed and the Adriatic Sea closed off in 50 – 70 million years . In the Northern Adriatic , the coast of the Gulf of Trieste and western Istria is gradually subsiding , having sunk about in the past two thousand years . In the Middle Adriatic Basin , there is evidence of Permian volcanism in the area of Komiža on the island of Vis and the volcanic islands of Jabuka and Brusnik . Earthquakes have been observed in the region since the earliest historical records . A recent strong earthquake in the region was the 1979 Montenegro earthquake , measuring 7.0 on the Richter scale . Historical earthquakes in the area include the 1627 Gargano peninsula and the 1667 Dubrovnik earthquakes , both followed by strong tsunamis . In the last 600 years , fifteen tsunamis have occurred in the Adriatic Sea
1979 Montenegro earthquake
1979 Montenegro earthquake
Adriatic Sea