Evidence of active subsidence at Basiluzzo island (Aeolian islands, southern Italy) inferred from a Roman age wharf

The Aeolian Arc (Southern Tyrrhenian Sea, Italy) is one of the most active volcanic areas of the Mediterranean
basin, affected by volcanic/hydrothermal and seismic activity. Ancient populations settled this
region since historical times, building coastal installations which currently are valuable archaeological
indicators of relative sea level changes and vertical land movements. In this study we show and discuss
data on the relative sea level change estimated from a submerged wharf of Roman age dated between 50
B.C. and 50 A.D., located at Basiluzzo Island. This structure has been studied through marine surveys and
archaeological interpretations and is presently located at a corrected depth of 4.10 0.2 m. We explain
this submergence by a cumulative effect of the relative sea level change caused by the regional glaciohydro-
isostatic signal, active since the end of the last glacial maximum, and the local volcano-tectonic
land subsidence. Finally, a total subsidence rate of 2.05 0.1 mm/yr 1, with a volcano-tectonic contribution
of 1.43 0.1 mm/yr 1 for the last 2 ka BP, is inferred from the comparison against the latest
predicted sea level curve for the Southern Tyrrhenian Sea, suggesting new evaluations of the volcanotectonic
hazard for this area of the Aeolian islands.