Publication Date:
2017-04-04
Description:
Volcaniclastic debris fl ows generated in drainage basins of the Apennine mountains
of southern Campania in response to pyroclastic fall deposition from four Holocene
eruptions of Somma-Vesuvius: Avellino (3.8 ka), A.D. 79, A.D. 472, and A.D. 1631.
These syneruptive debris fl ows are lithologically homogeneous and contain more than
90% of material from the parental eruption. They differ from inter-eruptive debris
fl ows recognized in the area, which contain mixed lithologies of juvenile material
(i.e., volcanic material from different eruptions). Diffuse rill erosion generated fi nesrich
volcaniclastic fl ows (mudfl ows), whereas partial saturation of coarse ash and
lapilli generated coarser-grained debris fl ows. Lithofacies analysis shows that debris
fl ows predominate versus hyperconcentrated fl ows and normal stream-fl ow deposits.
Debris-fl ow deposits are massive, matrix supported, and have a gravelly-sandy texture.
Large blocks are scarce due to their absence in the pyroclastic source material.
Lithofacies association indicates that volcaniclastic debris-fl ow deposits aggraded
rapidly by superimposition of different surges that spontaneously developed within
the fl ow. Bulk-fl ow density ranges from 1840 to 2260 kg/m3 (mean 2035 ± 207 kg/m3).
Geological data supported some considerations of hazard assessment in the study
area and indicate that the syneruptive volcaniclastic fl ows stopped distally on active
alluvial fans.
Description:
Published
Description:
217-235
Description:
1V. Storia e struttura dei sistemi vulcanici
Description:
N/A or not JCR
Description:
restricted
Keywords:
volcanic hazard
;
volcaniclastic debris fl ow
;
volcaniclastic sedimentation
;
Holocene
;
04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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