Mass Movement Hazard Assessment at a Medium Scale Using Weight of Evidence Model and Neo-predictive Variables Creation

2019 ◽  
pp. 73-85 ◽  
Author(s):  
Mohamed Mastere
Keyword(s):  
Hazard Assessment ◽  
Mass Movement ◽  
Weight Of Evidence ◽  
Medium Scale ◽  
Predictive Variables ◽  
Evidence Model

Mapping Susceptibility Landslide by Using the Weight-of-evidence Model: A Case Study in Merek Valley, Iran

2007 ◽  
Vol 7 (22) ◽  
pp. 3342-3355 ◽  
Author(s):  
M.H. Rezaei Mog ◽  
M. Khayyam ◽  
M. Ahmadi ◽  
M. Farajzadeh
Keyword(s):  
Weight Of Evidence ◽  
Evidence Model

Potential of weight of evidence modelling for gully erosion hazard assessment in Mbire District – Zimbabwe

2014 ◽  
Vol 67-69 ◽  
pp. 145-152 ◽  
Author(s):  
F. Dube ◽  
I. Nhapi ◽  
A. Murwira ◽  
W. Gumindoga ◽  
J. Goldin ◽  
...  
Keyword(s):  
Hazard Assessment ◽  
Gully Erosion ◽  
Weight Of Evidence ◽  
Erosion Hazard

scholarly journals Assessment of landslide susceptibility for civil protection purposes by means of GIS and statistical analysis: lessons from the Province of Modena, Italy

2017 ◽  
Vol 19 (1) ◽  
pp. 29-43
Author(s):  
LIBERATOSCIOLI Elena ◽  
VAN WESTEN Cees J. ◽  
SOLDATI Mauro
Keyword(s):  
Landslide Susceptibility ◽  
Risk Mitigation ◽  
Mass Movement ◽  
Critical Issue ◽  
Weight Of Evidence ◽  
Slope Position ◽  
Landslide Risk ◽  
Civil Protection ◽  
Multi Temporal ◽  
Position Index

This paper is focused on the analysis of landslide susceptibility for civil protection purposes. A methodology was developed and applied to support measures aiming at landslide risk mitigation. It is based on GIS and the Weight of Evidence (WofE) method, which was preferred among several other statistical approaches because it is suitable for large areas, easy to interpret and simple to program. The latter feature is important for implementing a GIS tool aimed to facilitate Civil Protection in the updating of susceptibility maps. An application of the methodology was performed in a mountainous and hilly area of the Northern Apennines (Italy) located in the Province of Modena where landslides are a critical issue in terms of civil protection due to the recurrent damages to buildings, roads and infrastructures. According to the Region Emilia-Romagna Landslide Inventory Map (RER LIM), shallow slides and earth flows are by far the most widespread mass movement types. Hence, the susceptibility assessment concerned these two types of movements. The choice of the training set, based on active landslides, took into account possible limitations of the input data. The predisposing factors were lithology, slope, curvature, Slope Position Index, aspect, land use, distance from roads. The validation was conducted through the PRC and SRC curves, and direct checking (comparison with past occurrences, multi-temporal orthophotos and field surveys). The resulting models predicted the location of landslides in an acceptable manner. One map for each type of landslides was produced and afterwards they were combined in a single document to improve their intelligibility in a civil protection framework.

Stratigraphic and chemical correlation of volcanic ash beds in the terminal Proterozoic Nama Group, Namibia

2005 ◽  
Vol 142 (5) ◽  
pp. 519-538 ◽  
Author(s):  
BEVERLY Z. SAYLOR ◽  
JANICE M. POLING ◽  
WARREN D. HUFF
Keyword(s):  
Large Scale ◽  
Volcanic Ash ◽  
Weight Of Evidence ◽  
Multivariate Statistical ◽  
Sequence Stratigraphic ◽  
Element Abundances ◽  
Medium Scale ◽  
Testing Sequence ◽  
Stratigraphic Position ◽  
Study Support

At least twenty silicified volcanic ash beds have been identified in the Kuibis and Schwarzrand subgroups of the terminal Proterozoic Nama Group of Namibia. Nineteen of the Nama ash beds are in the Schwarzrand Subgroup in the Witputs subbasin. Two of these are in the siliciclastic-dominated lower part of the subgroup, which consists of the Nudaus Formation and Nasep Member of the Urusis Formation and comprises two depositional sequences. Identification and correlation of these ash beds are very well known based on stratigraphic position. Sixteen ash beds are contained within the carbonate-dominated strata of the Huns, Feldschuhhorn and Spitskop members of the Urusis Formation. These strata comprise four large-scale sequences and eighteen medium-scale sequences. Ash beds have been found in three of the large-scale sequences and seven of the medium-scale sequences. Correlations are proposed for these ash beds that extend over large changes in facies and stratal thickness and across transitions between the seaward margin, depocentre and landward margin of the Huns-Spitskop carbonate shelf. A study of whole rock and in situ phenocryst compositions was conducted to evaluate the feasibility of independently testing sequence stratigraphic correlations by geochemically identifying individual ash beds. Whole rock abundances of Al, Fe, Mg, K and Ti vary inversely with Si, reflecting variations in phenocryst concentration due to air fall and hydrodynamic sorting. These sorting processes did not substantially fractionate whole rock rare earth element abundances (REE), which vary more widely with Si. REE abundances are higher in samples of the Nudaus ash bed than in samples of the Nasep ash bed, independent of position in bed, phenocryst abundance, or grainsize, providing a geochemical means for discriminating between the two beds. Variations in the position of chondrite-normalized whole rock REE plots similarly support suspected correlations of ash beds between widely separated sections of the Spitskop Member. Abundances of Fe, Mg and Mn in apatite plot in distinct clusters for Spitskop ash beds that are known to be different and in clusters that overlap for ash beds suspected of correlating between sections. Abundances of REE in monazites differ for the Nudaus, Nasep and Spitskop ash beds in which these phenocrysts were identified. Multivariate statistical analysis provided a quantitative analysis of the discriminating power of different elements and found that whole rock abundances of Ge, Nb, Cs, Ba and La discriminate among the whole rock compositions of the Nudaus and Nasep ash beds and the Spitskop ash beds that are thought to correlate between sections. Each of the above geochemical signatures, by itself, is not definitive because the differences between beds are comparable to the variability within beds and because some signatures are shared by beds known to be different. Taken together, however, weight-of-evidence arguments based on multiple components and phases can successfully discriminate among Nama ash beds. Results from this study support sequence stratigraphic correlations of Spitskop ash beds that document stratal truncations and gaps in the record related to onlap and erosion.

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