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Open-slope, translational submarine landslide in a tectonically active volcanic continental margin (Licosa submarine landslide, southern Tyrrhenian Sea)
- Source :
- Geological Society, London, Special Publications; 2019, Vol. 477 Issue: 1 p133-150, 18p
- Publication Year :
- 2019
-
Abstract
- The southern Tyrrhenian continental margin is the product of Pliocene–Recent back-arc extension. An area of approximately 30 km2of gentle (about 1.5°) lower slope of the last glacial outer shelf sedimentary wedge in water depths of between 200 and 300 m failed between 14 and 11 ka BP. We approached the landslide by multibeam and sub-bottom profiler surveying, high-resolution multichannel seismics, and coring for stratigraphic and geotechnical purposes. With regard to a slope-stability analysis, we carried out an assessment of the stratigraphic and structural setting of the area of the Licosa landslide. This analysis revealed that the landslide detached along a marker bed that was composed of the tephra layer Y-5 (c.39 ka). Several previously unknown geological characteristics of the area are likely to have affected the slope stability. These are the basal erosion of the slope in the Licosa Channel, a high sedimentation rate in the sedimentary wedge, earthquake shaking, the volcanic ash nature of the detachment surface, subsurface gas/fluid migration, and lateral porewater flow from the depocentre of wedge to the base of the slope along the high-permeability ash layers. A newly discovered prominent structural discontinuity is identified as the fault whose activity may have triggered the landslide.
Details
- Language :
- English
- ISSN :
- 03058719 and 20414927
- Volume :
- 477
- Issue :
- 1
- Database :
- Supplemental Index
- Journal :
- Geological Society, London, Special Publications
- Publication Type :
- Periodical
- Accession number :
- ejs51074275
- Full Text :
- https://doi.org/10.1144/SP477.34