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| Titel |
Evidence of slope instability in the Southwestern Adriatic Margin |
| VerfasserIn |
D. Minisini, F. Trincardi, A. Asioli |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1561-8633
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| Digitales Dokument |
URL |
| Erschienen |
In: Natural Hazards and Earth System Science ; 6, no. 1 ; Nr. 6, no. 1 (2006-01-02), S.1-20 |
| Datensatznummer |
250003276
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| Publikation (Nr.) |
 copernicus.org/nhess-6-1-2006.pdf |
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| Zusammenfassung |
| The Southwestern Adriatic Margin (SAM) shows evidence of widespread failure
events that generated slide scars up to 10 km wide and extensive slide
deposits with run out distances greater than 50 km. Chirp-sonar profiles,
side-scan sonar mosaics, multibeam bathymetry and sediment cores document
that the entire slope area underwent repeated failures along a stretch of
150 km and that mass-transport deposits, covering an area of 3320 km2,
are highly variable ranging from blocky slides to turbidites, and lay on the
lower slope and in the basin. The SAM slope between 300–700 m is impacted by
southward bottom currents shaping sediment drifts (partly affected by
failure) and areas of dominant erosion of the seafloor. When slide deposits
occur in areas swept by bottom currents their fresh appearence and their
location at seafloor may give the misleading impression of a very young age.
Seismic-stratigraphic correlation of these deposits to the basin floor,
however, allow a more reliable age estimate through sediment coring of the
post-slide unit. Multiple buried failed masses overlap each other in the
lower slope and below the basin floor; the most widespread of these
mass-transport deposits occurred during the MIS 2-glacial interval on a
combined area of 2670 km2. Displacements affecting Holocene deposits
suggest recent failure events during or after the last phases of the last
post-glacial eustatic rise. Differences in sediment accumulation rates at
the base or within the sediment drifts and presence of downlap surfaces
along the slope and further in the basin may provide one or multiple
potential weak layers above which widespread collapses take place.
Neotectonic activity and seismicity, together with the presence of a steep
slope, represent additional elements conducive to sediment instability and
failure along the SAM. Evidence of large areas still prone to failure
provides elements of tsunamogenic hazard. |
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