Late Holocene tsunami imprint at the entrance of the Ambrakian gulf (NW Greece)
This paper presents geomorphological, sedimentological and geoarchaeological evidence of multiple tsunami impacts on the Aktio headland (NW Greece). Numerous vibracores revealed high energy event deposits most of which were accumulated on terrestrial sites on top of erosional unconformities. The tsu...
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| Xuất bản năm: | URI:https://journals.openedition.org/mediterranee, |
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| Những tác giả chính: | , , , , |
| Định dạng: | Article ou chapitre numérique |
| Ngôn ngữ: | Anglais |
| Được phát hành: |
Méditerranée
2009
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| Truy cập trực tuyến: | Accès Université d'Orléans et IFPM Accès Université d'Orléans et IFPM |
| Tóm tắt: | This paper presents geomorphological, sedimentological and geoarchaeological evidence of multiple tsunami impacts on the Aktio headland (NW Greece). Numerous vibracores revealed high energy event deposits most of which were accumulated on terrestrial sites on top of erosional unconformities. The tsunami sediments, up to 3 m thick, mostly consist of middle to coarse sand and include gravel and marine shell fragments. Both badly sorted and well sorted, laminated event deposits were observed. In several places, an intersecting palaeosol unit documents repeated tsunamigenic influence after a phase of weathering and soil formation. Underwater studies offshore Aktio headland showed that the Plaka palaeo beach ridges, including its beachrock base, out of beachrock was destroyed by tsunamigenic wave activity. Dislocated beachrock fragments with a maximum diameter of 60 cm were encountered on Aktio headland up to 2.5 km to the west of the in-situ beachrock unit in elevations up to 3.15 m a.s.l.A series of 14C-AMS dates and diagnostic ceramic fragments found in vibracores allow to reconstruct several tsunami landfalls. Around 2870-2350 cal BC, a major event hit the entire headland. Parts of the study area were probably affected by further tsunamis around 1000 cal BC and 300 cal BC which are known to have hit the adjacent Lefkada coastal zone. A mega tsunami struck the Aktio headland around 840 cal AD. The minimum height of the tsunami surge is estimated at 6m. Further tsunami landfalls occurred during the last 700 or so years. The results document an extraordinarily high tsunami risk for the study area. |
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