International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XXXIX-B8, 2012
XXII ISPRS Congress, 25 August — 01 September 2012, Melbourne, Australia
phenomenon that a large number of mountain materials
suddenly downward slides along a sliding surface of the
interior in the gravity by a variety of external factors, for
instance, earthquake, volcano, river erosion, snow melt, rainfall
and human activities (Kirschbaum et al, 2010). Especially, the
destructive force of other secondary disasters induced by large
landslide far exceeds its direct damage. In recent years,
mudslides which were affected by global climate change
occurred frequently. More than 90,000 landslide hidden
dangers are located in 70 cities and counties of several southern
and north-western provinces in China, and tens of millions of
people live under the threat of landslide throughout the year.
Landslide caused thousands of deaths and tens of billions of
property loss (Zhou et al, 2005). Therefore, landslide
monitoring, assessment and prediction are advanced subjects of
international landslide disaster research and environmental
engineering geology field nowadays.
Many causes of landslide occurrence mainly include terrain,
geology, geomorphy, weather conditions, land cover, and so on
(Parry, 2011). Obtaining the relationships between these above
factors and landslide occurrence is very important for the
quantitative evaluation of landslide susceptibility (LS) and
hazards. LS assessment is the quantitative or qualitative
evaluation for the existing or potential type, volume,
distribution of some area’s landslide, and LS mapping would
conduce to us the space distribution of one regional slope
instability probability (Mathew et al, 2008). It is the first and
most step of landslide risk assessment, in order to make
effective measures of landslide mitigation. Reliable
susceptibility assessment depends on the quality and range of
the available data and the selection of method for modelling to
identify landslide, analyze landslide formation conditions and
characteristics, show landslide detailed geometric description.
LS assessment typically excludes the prediction of occurrence
time, is an important feature of susceptibility evaluation
(Ercanoglu, 2008).
Based on historical data and practical experience, empirical
landslide susceptibility assessments adopt the statistical
approach and pattern recognition methods to construct
empirical models. Meanwhile, empirical weights of landslide
factors can be obtained by the initial analysis; and spatial
associations between spatial factors and landslides will be
showed in a GIS (Geographic Information System). Artificial
neural network (ANN) can analyze complex data at different
scales such as continuous, indexical and binary data (Chauhan
46
et al, 2010). Based on learning from data with known
characteristics to obtain the weights of factors, ANN is used to
recognize the unseen data (Pradhan, 2011). In this paper, we
used the ANN black box by capturing the connection weights
among various inputs, with multi-temporal ground and remote
sensing satellite data for susceptibility evaluation and mapping
of China’s landslide disaster.
2. STUDY AREA AND DATA
China lies in the east of the Asia-Europe Continent, on the
western shore of the Pacific Ocean, and covers about 9.6
million km2 land area (between latitudes 3.85°N and 53.56°N,
between longitudes 73.55°E and 135.08°E). The terrain of
China is high in east but low in west. Mountain, plateau and
hills cover about 67% of the land area; basin and plain cover
about 33%. China is one of the countries which are most
vulnerable to landslide disaster. Some studies indicated that
landslide disaster mainly happened in a steep slope such as the
river and stream coast of bank slope zone, and the gorges with
high level difference; in geological tectonic belt (fractures or
structural zones); in the soft rock-soil (loose covering layer,
loess, mudstone, shale, coal beds); in some areas with heavy
rainfall (He et al, 2008).
The reports of the landslide events for nearly 60 years were
obtained mainly from online news reports, yearbooks, and
hazard database, including: China Geological Environmental
Information Network (CGEIN, http://www.cigem.gov.cn/);
China Risk Network (CRN, http://www.irisknet.cn/); Geostress
and Geological Disaster Querying Database (GGDQD,
http://www.geomech.ac.cn/geo0503/); China Statistical
Yearbook (1950-2011); China major landslide reports (from
newspaper and media). Since the 1980s, numbers of reports
started to increase, concerned with the government’s attention.
To be emphasized, numbers of landslide reports of the south
and southwest are more than that of other regions.
Many causes of landslide occurrence previous mentioned can
be divided into two main categories (Wu and Sidle, 1995):
(1) Internal factors: those that have decision effects on
landslide, including geology, geomorphology, slope gradient,
slope aspect, elevation, soil property, vegetation cover, flow
distribution, fracture, and so on.
(2) External factors: they will trigger landslide suddenly, such
as earthquake, rainfall.
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