Vol. 8(4) April 2015
Land use land cover changes in pre- and post- earthquake
affected area using Geoinformatics – Western Coast of Gujarat, India
Guru Balamurugan and Sridhara Aravind M.
Natural disaster is one of the major concerns around
the world which leads to loss of life, damage to property and drastic changes in
land use and land cover (LULC). Especially, earthquakes induce the huge damages
to properties, communities, economics aspects as well as changes of LULC. In post
earthquake scenario, the nation has to develop the various strategies to restore
and rehabilitate the affected area. The present research brings out the LULC changes
and the major transitions observed during the post-disaster scenario in Mundra coastal
area, India. To analyze the temporal changes of LULC, various data sets viz. toposheets,
satellite images, field and collateral data were used. Using supervised classification
technique the pre (1999 and 2000) and post (2010) earthquake LULC maps were prepared.
The output shows decline in the agricultural and scrubland, increase in fallow land
and saltpans and exponential increases of built up area in the area.
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Experimental investigations on lateral behaviour of
pile groups in sand
Kesavan G. and Chandrasekaran S. S.
This paper presents the results of experimental investigations
on the behaviour of 1 × 2, 2 × 2, 2 × 3 model pile groups with free head condition
embedded in sand under static lateral loading. The effects of spacing, embedded
length, size of group and relative density on load-deflection behaviour of pile
group are investigated. Group interaction effects, lateral capacity of pile groups,
efficiency and critical spacing are evaluated. Results indicate strong nonlinear
behaviour of pile group under lateral loading. It is found that for 2 3 pile group
with spacing to diameter (S/D) ratio of 3, the lateral load capacity is reduced
by about 32%. Efficiency of closely spaced pile groups is less due to group interaction
caused by the shadowing effect. The group efficiency for a pile group with three
diameter spacing reduces to about 25% when the number of piles in the group increases
from 2 (1 2 group) to 6 (2 3 group). The critical spacing is found to be 5D
and 7D for 1 × 2 and 2 × 2 pile groups respectively.
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Actual Soil Erosion Risk Mapping using Modified CORINE
Method
Jafari Golam Hasan, Feyzolahpour Mehdi and Noruzi Mohammad Reza
Excessive erosion causes both 'on-site' and 'off-site'
problems. On-site impacts include decreases in agricultural productivity and (on
natural landscapes) ecological collapse, both because of loss of the nutrient-rich
upper soil layers. In some cases, the eventual end result is desertification. Off-site
effects include sedimentation of waterways and eutrophication of water bodies as
well as sediment-related damage to roads and houses. The loss of soil fertility
due to erosion is further problematic because the response is often to apply chemical
fertilizers leading to further water and soil pollution, rather than to allow the
land to regenerate. Monitoring and modeling of erosion processes can help us better
understand the causes, make predictions and plan how to implement preventative and
restorative strategies. CORINE model is used to estimate the soil erosion. This
method has used erodibility, erosivity, slope, vegetation factors to evaluate the
actual soil erosion. In this study, CORINE model was modified according to the study
area’s climate and was used to analyze the soil erosion risk in Gharatapeh watershed.
The soil erodibility also was estimated based on texture, depth and gravel amount.
Actual soil erosion risk map was prepared by integrating the erodibility and erosivity
maps by vegetation cover map. Results indicated that more than 57.5% of the Gharatapeh
watershed had high potential soil erosion risk and the actual soil erosion was 38.7%.
Low erosion potential and actual erosion values were 7.52% and 42.37% respectively.
Areas with high actual erosion were detected in parts with high precipitation, maximum
slope and minimum vegetation cover. Results demonstrate the role of vegetation cover
in soil conservation.
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Investigation and assessment of a landslide case study
in southwestern Taiwan
Hsiao Darn-Horng, Phan-To Anh-Vu, Kung Gordon Tung-Chin and Liao Chieh-Jui
This study presents an experimental investigation on
subsurface displacements evaluated by means of boreholes, rainfall, groundwater
level, inclinometer system and ERT technique in Chaishan area, Kaohsiung, Taiwan.
From 2003, the local government provided financial funding support for the geotechnical
program with expectancy to understand and reduce the damage due to the deformation
and landslide. The boreholes were bored in 2004 and 2013 to detect the strata of
geological condition. In the meanwhile, an inclinometer system was installed, consisting
in fifteen positions to measure the movement of subsurface from 2005 to 2012. To
facilitate understanding more geological strata, the Electrical Resistivity Topography
technique was employed to obtain continued geological cross-sections and to complement
the results of borehole technique. Results showed that strata are composed of limestone,
silty clay and mudstone distributed with different depths in the survey area. ERT
elucidated that surface is found by heterogeneous layers, including not only limestone
but also limestone interbedded with silty clay. Inclinometers revealed that movement
of subsurface gradually increases with increasing observation time, especially for
rainy reason. Close to Taiwan Strait had a displacement rate of subsurface more
than 10 mm per year, the movements were mainly towards South-West direction. In
addition, a combination of steep terrain, weak geology and rainfall is main reason
for the landslide and deformation of the subsurface in the study area. Finally,
factor of safety against landslide obtained from STABL6 software indicated that
some places of this area are in critical equilibrium in the range of 0.9 and 1.93
and the risk of damage is thus predicted to continuously occur in the future.
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What happens next? Prediction of Disastrous Links
in Covert Networks
Karthika Subbaraj and Bose Sundan
Covert network is a social community with a lot of secrecy
and influence which behaves in a stealthy and concealed manner to achieve their
goals. Realizing the threat posed by these networks, understanding and modeling
the evolution of these networks are therefore fundamental issues and active areas
of research. The major objective of this work is classical link prediction problem
that attracts particular interest. In Link Prediction, given a snapshot of clandestine
network at time t, the methodology aims to predict links (e.g. friendships) that
will emerge in the network between t and a later time t’. The missing link problem
has important ramifications as these links can alter estimates of network-level
statistics. The ability to infer the new links helps to detect the future attacks
by covert networks. An effective prediction methodology is proposed by resolving
the attribute inference problem which is treated as minor objective of this work.
The negligence of tie strength and attribute link weights in existing works has
been overcome by designing the attribute-augmented network model. The performance
of the system is experimented on the September 11, 2001 attack.
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