Publication Date:
2020-02-24
Description:
A significant part of Campania is extensively covered by volcaniclastic soils,
deriving from the alteration of airfall-sedimented formations of layered ashes and pumices
that were ejected by Campi Flegrei and Mt. Somma–Vesuvius during explosive eruptions.
Where such soils cover steep slopes cut in carbonate bedrock, landforms depend essentially
on the morpho-evolution of such slopes prior to the deposition of the volcaniclastic soils,
because these are generally present only as thin veneers, up to a few meters of total
thickness. Historical records and local literature testify that, in this part of Campania,
landslides that originate on carbonate slopes covered by such soils and terminate at their
foot or at gully outlets are frequent, following critical rainfall events. Such landslides can
be classified as complex, occurring initially as debris slides, but rapidly evolving into
debris avalanches and/or debris flows. The localization of the initial sliding areas (i.e.
‘‘sources’’) on the slopes depends on both the spatial distribution of characters of the soil
cover and the spatial distribution of the triggering rainfall events. It therefore appears
reasonable to separate the two aspects of the problem and focus on the former one, in order
to attempt an assessment of soil sliding susceptibility in the event of landslide-triggering
rainfall. In this paper, some results of the application of a method aimed at such an
assessment are presented. The method, called SLIDE (from SLiding Initiation areas
DEtection), is based on the concept that, for a spatially homogeneous soil cover and a
spatially homogeneous landslide-triggering rainfall sequence, different values of threshold
slope gradient for limit equilibrium conditions exist, depending on morphological characters
of the soil cover, such as its continuity and planform curvature. The method is based
on the assessment of (1) soil cover presence, (2) discontinuities within soil cover, (3) slope
gradients and curvature, by means of good resolution DEMs. It has been applied to sample carbonate slopes of Campania, where landslides originated either repeatedly or recently.
Results are encouraging, and a soil sliding susceptibility map of a large area, based on a simplified version of method, is also presented.
Description:
Published
Description:
155-168
Description:
5.5. TTC - Sistema Informativo Territoriale
Description:
JCR Journal
Description:
reserved
Keywords:
Debris-slide susceptibility
;
Volcaniclastic soil cover
;
Soil cover discontinuities
;
Planform curvature
;
05. General::05.08. Risk::05.08.02. Hydrogeological risk
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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