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Products
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The
SLAM products have been defined according to the Swiss and
Italian legislation and the user requirements. The products are
developed starting from the methodologies actually employed in
the risk management; in this way they can be easily merged in
the user database.
In particular, the products are focused on the forecasting phase,
aiming at the landslide risk identification and at the
monitoring of mass movements inducing high risk scenarios.
The
following tables summarize the products
and services specifications as required by the users.
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Users: Arno
River Basin National Authority and Regione Campania
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Product
description
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Update
frequency
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Spatial
Scale
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Spatial
resolution
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Accuracy
(vertical,%)
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Requested
format
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Landslide
Motion Survey
Detection of unknown unstable areas; updating of the
information about state and distribution of activity;
evaluation of intensity or danger.
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seasonal
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1:25,000
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20
m for geographical location
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1
cm for movement
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GIS
compatible
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Displacement
Monitoring Service
Service to monitor superficial deformation rates, to
evaluate dimensions and temporal evolution.
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seasonal
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1:2,000
- 1:10,000
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5
m for geographical location
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mm
order for movement
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GIS
compatible
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Landslide
Susceptibility Mapping
Integration of synoptic information derived from RS in
the processes of hazard mapping
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Every
4 years
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1:25,000
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20
m for geographical location
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--
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GIS
compatible
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Users:
Swiss Cantonal Autorities
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| Product
description |
Update
frequency |
Spatial
Scale |
Spatial
resolution |
Accuracy
(vertical,%) |
Requested
format |
Landslide
Motion Survey Creation
of landslides inventory maps extended over all the test
area, with indication on mass movement activity
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Depending
on site (often annually)
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1:10,000
– 1:50,000
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20
to 40 m
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Acceptable:
2 cm
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GIS
compatible (Arcview shape file) and paper
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Landslide
Displacement Monitoring
Displacement
rates over several time intervals on a given area of
interest.
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Depending
on site, typically seasonable updating
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1:3,000
– 1:10,000
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3
to 10 m
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Sub-centimeters
accuracy
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GIS
compatible (Arcview shapefile)
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Landslide
Susceptibility Mapping Hazard
map extended beyond the limits of inhabited areas. This
would enable a better knowledge of the territory under
jurisdiction.
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Every
3 years
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1:5,000
– 1:10,000
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10
m
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--
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GIS
compatible (Arcview shapefile); ("raw" data to
be interpreted)
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Landslide
Motion Survey
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The
Landslide Motion Survey identifies the areas affected by
landslides for the whole hydrographic basin, or for a
significant portion of it. This large scale product could be a
useful support for the geological risk service agencies in their
activities related to the updating of landslide inventories and
the planning of structural intervention.
Landslide
Motion Survey represents a landslide inventory map with specific
characteristics directly derived from the end user requirements.
The map reports the spatial distribution of the landslides, the
description of their state of activity, the typology and other
information which can be obtained through the use of EO and
traditional data.
The input data employed to produce this product is summarized
below:
The
integration of the information coming
from the interferometric analysis within the landslide inventory
map provided by the user is performed in a GIS environment. The
first step is the map overlaying of the results of
interferometric analysis on the users dataset (i.e., landslide
polygons, lineaments layer and topographic map). The compliance
analysis of the two datasets, in terms of landslides
distribution and state of activity, allows to identify possible
discrepancies which are analysed by means of the interpretation
of SPOT5 images draped on the high accuracy DEM, stereo/monoscopic
aerial-photos and field surveys. Such analysis is able to
provide information about the landslides spatial distribution
and to detect changes in landslide polygon boundaries and to
identify new unstable areas with consequent creation of new
polygons. In addition, it provides information about the
landslide state of activity, allowing to confirm or modify the
polygons state of activity (i.e., active, dormant and inactive).
In
Italy, the service has been performed for
the whole extent of Arno river basin (about
9,000 km2) and for an area of about 900 km2 in Campania region.
Meanwhile in Switzerland, the service
has been performed the geographic areas of
Canton Ticino, eastern Valais and Berne Cantons.
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Landslide
Displacement Monitoring
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This
product allows the monitoring of the areas of interest on a
reduced scale basis. The objective is to quantify accurately the
deformation velocity of unstable areas through the displacement
rate measurement of some points located within identified
landslides. The outputs could be used to monitor the areas
characterized with high hydro-geological risk, and to test the
effectiveness of structural interventions.
The
product consists of a monographic report related to a large mass
movement inducing a high risk situation, which includes
a geological modelling study of the phenomenon, obtained from
the integration of monitoring data (in-situ and EO-derived)
with the geological-geomorphologic characteristics of the
site.
The
input data employed in order to produce
the Landslide Displacement Monitoring can be summarized as
follows:
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in-situ
measurements (inclinometric readings, GPS, extensometers,
topographic surveys, etc.);
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aerial
photos (stereoscopic and monoscopic at 1:10,000 scale);
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Advanced
Permanent Scatterers Analysis (APSA)/Interferometric Point
Target Analysis;
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high
accuracy DEM (10 m cell-size);
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technical
reports and databases (SCAI, AVI);
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geomorphologic
and geologic maps.
The
activity foresee a preliminary collection and review of the
bibliographic information. After this first step the map overlaying
of the interferometric analysis on an existing geomorphologic
map is performed in order to define the areas affected by
movement and the zone with different deformation rates.
Discrepancies are analysed by means of interpretation of
aerial-photos and field surveys. The comparison and integration
of in-situ vs. EO measurements and the analysis of such
monitoring data with reference to the geological features allow
to better understand the geological model of the phenomenon.
The
Landslide Displacement Monitoring is developed in Italy for
Campania region and Arno River Basin in the test sites of
Poggibonsi, Pelago, Chianciano and Capannori. For Switzerland
the product has been tested on the following test sites:
Grubengletscher, Grindelwald, Wengen, Lauterbrunnen,
Gräechen, La Frasse and Montagnon, Biasca, Preonzo, Airolo, and
the area around Schwarzsee
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Landslide
Susceptibility Mapping
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The
Landslide Susceptibility Mapping classifies the area of interest
with respect to different classes of landslide hazard. The
product is realized through the integration of the information
concerning the millimetric ground displacements, resulting from
the two products described above, with the thematic maps of land
use, slope, geomorphology, and more. The Landslide
Susceptibility Mapping could support geological hazard mapping
and could be considered as an important tool for land use
planning and environmental impact assessment.
Hazard
is one of the component that contributes to the definition of
landslide risk and it is defined as the probability that a
mass movement may occur in a defined area during a given period
of time.
The
landslide hazard map which will be
realized for the Italian test sites within the SLAM project
consists of a zonation of the studied area in 5 different levels
of hazard, as summarized in the following
table, assessed by integrating the EO-derived information with
those acquired from traditional sources.
| Level |
Description |
Return
period |
Annual
probability |
| H0 |
Hazardless
area, in which geomorphological processes and soils
physical features are not favourable to landslide
trigger.
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- |
-
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| H1 |
Areas
with geological and morphological conditions
unfavourable to slope stability, without morphological
indicators of movement at the present.
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1000 |
0,001 |
| H2 |
Areas
with geological and morphological conditions very
unfavourable to slope stability, without morphological
indicators of movement at the present; areas in which
only stabilazed landslides are present.
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100 |
0,01 |
| H3 |
Areas
in which geomorphological indicators of slope
instability occur, so new trigger-landslides are
possible within a long-term period; areas with dormant
landslides subject to long-term reactivation.
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10 |
0,1 |
| H4 |
Areas
in which active landslides are present; areas with
indications of incipient movement; areas involved by
expansion of an active landslide.
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2 |
0,5 |
The
input data used to realize this product are summarized below:
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Landslide
Motion Survey;
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Landslide
Displacement Monitoring;
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landslide
factors: slope, lithology, land cover, profile curvature,
upslope contributing area;
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technical
reports and user databases.
According
to the user requirements, the hazard analysis on the Arno Basin
territory has been organized in the following three main steps:
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landslide
prone areas identification: definition of
homogeneous terrain units (HTU) by means of the intersection
of instability factors. The statistical analysis of the HTUs
and the spatial distribution of landslide (Landslide Motion
Survey Product) through the use of different techniques (multivariate
statistics-ANN) allows to define the lower hazard level H0,
H1, H3. In this way only landslide prone areas are mapped;
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temporal
factor analysis: reclassification of the mapped
landslide in three higher hazard levels (H2, H3, H4) by
taking into account the state of activity derived by the
Landslide Motion Survey, monitoring data (Landslide
Displacement Monitoring and traditional ones) and historical
information (AVI, SCAI, IFFI databases). In particular such
classification will be performed by evaluating the return
periods of each mass movements. The class H4 will be defined
with reference to the 2 years return period, the class H3
with reference to the 10 years return period and the H2 to
the 100 years return periods. Such temporal limits have been
identified by analysing the more widespread typology of
landslides in the Arno River Basin.;
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landslide
hazard mapping: overlaying of the classification
based on the temporal factor on the landslide prone areas
zonation. In case of differences and conflicts between the
two zonations the first one will be the guide to the final
one.The consequent classification in 4 hazard classes plus a
hazardless area represents the final hazard map.
In
Italy this product is realized only on the Arno basin.
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