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1.
Landslide susceptibility mapping of vicinity of Yaka Landslide (Gelendost,Turkey) using conditional probability approach in GIS 总被引:4,自引:0,他引:4
Adnan Ozdemir 《Environmental Geology》2009,57(7):1675-1686
On 19 February 2007, a landslide occurred on the Alaard?ç Slope, located 1.6 km south of the town of Yaka (Gelendost, Turkey.) Subsequently, the displaced materials transformed into a mud flow in E?lence Creek and continued 750 m downstream towards the town of Yaka. The mass poised for motion in the Yaka Landslide source area and its vicinity, which would be triggered to a kinetic state by trigger factors such as heavy or sustained rainfall and/or snowmelt, poise a danger in the form of loss of life and property to Yaka with its population of 3,000. This study was undertaken to construct a susceptibility mapping of the vicinity of the Yaka Landslide’s source area and to relate it to movement of the landslide mass with the goal of prevention or mitigation of loss of life and property. The landslide susceptibility map was formulated by designating the relationship of the effecting factors that cause landslides such as lithology, gradient, slope aspect, elevation, topographical moisture index, and stream power index to the landslide map, as determined by analysis of the terrain, through the implementation of the conditional probability method. It was determined that the surface area of the Goksogut formation, which has attained lithological characteristics of clayey limestone with a broken and separated base and where area landslides occur, possesses an elevation of 1,100–1,300 m, a slope gradient of 15 °–35 ° and a slope aspect between 0 °–67.5 ° and 157 °–247 °. Loss of life and property may be avoided by the construction of structures to check the debris mass in E?lence Creek, the cleaning of the canal which passes through Yaka, the broadening of the canal’s base area, elevating the protective edges along the canal and the establishment of a protective zone at least 10-m wide on each side of the canal to deter against damage from probable landslide occurrence and mud flow. 相似文献
2.
Landslides are a recognized but poorly studied phenomena in the eastern footslopes of the Aberdare ranges in central Kenya.
The Aberdare ranges traverse the Murang'a, Kiambu, Nyeri and Nyandarua districts of Kenya where fatal landslides have occurred
in the past. A detailed study of a major landslide which occurred at Maringa village in Murang'a district on 30 April 1997,
has been undertaken. The landslide buried three houses at the toe of a slope and killed all the 11 occupants in their sleep.
It is shown that the geology and climate of the study area contribute to the prevalence of landslides not only in Murang'a
but in all the andosol-covered areas throughout the eastern footslopes of Aberdare ranges. Rapid weathering of pyroclastic
rocks in a warm and wet climate create a regolith which is generally weaker than the underlying better-cemented basalt and
basaltic agglomerates. The landsliding occurred when the weathered pyroclastic regolith become saturated after a heavy rainstorm
on high mechanically unstable slope which slid over the more stable basalts. Over-saturation of clay soils (andosol) which
were also derived from weathering of pyroclastic rocks contributed to the slope failure. The results of the study show that
besides fatalities and injuries, the landslide destroyed homes, plantations and roads.
Received: 16 March 1998 · Accepted: 22 September 1998 相似文献
3.
An approach for GIS-based statistical landslide susceptibility zonation—with a case study in the Himalayas 总被引:14,自引:1,他引:14
Ashis K. Saha Ravi P. Gupta Irene Sarkar Manoj K. Arora Elmar Csaplovics 《Landslides》2005,2(1):61-69
Landslide susceptibility zonation (LSZ) is necessary for disaster management and planning development activities in mountainous regions. A number of methods, viz. landslide distribution, qualitative, statistical and distribution-free analyses have been used for the LSZ studies and they are again briefly reviewed here. In this work, two methods, the Information Value (InfoVal) and the Landslide Nominal Susceptibility Factor (LNSF) methods that are based on bivariate statistical analysis have been applied for LSZ mapping in a part of the Himalayas. Relevant thematic maps representing various factors (e.g., slope, aspect, relative relief, lithology, buffer zones along thrusts, faults and lineaments, drainage density and landcover) that are related to landslide activity, have been generated using remote sensing and GIS techniques. The LSZ derived from the LNSF method, has been compared with that produced from the InfoVal method and the result shows a more realistic LSZ map from the LNSF method which appears to conform to the heterogeneity of the terrain. 相似文献
4.
A landslide susceptibility zonation (LSZ) map helps to understand the spatial distribution of slope failure probability in
an area and hence it is useful for effective landslide hazard mitigation measures. Such maps can be generated using qualitative
or quantitative approaches. The present study is an attempt to utilise a multivariate statistical method called binary logistic
regression (BLR) analysis for LSZ mapping in part of the Garhwal Lesser Himalaya, India, lying close to the Main Boundary
Thrust (MBT). This method gives the freedom to use categorical and continuous predictor variables together in a regression
analysis. Geographic Information System has been used for preparing the database on causal factors of slope instability and
landslide locations as well as for carrying out the spatial modelling of landslide susceptibility. A forward stepwise logistic
regression analysis using maximum likelihood estimation method has been used in the regression. The constant and the coefficients
of the predictor variables retained by the regression model have been used to calculate the probability of slope failure for
the entire study area. The predictive logistic regression model has been validated by receiver operating characteristic curve
analysis, which has given 91.7% accuracy for the developed BLR model. 相似文献
5.
Understanding rainfall-landslide relationships in man-modified environments: a case-history from Caramanico Terme, Italy 总被引:2,自引:0,他引:2
J. Wasowski 《Environmental Geology》1998,35(2-3):197-209
The expansion of Caramanico Terme in this century has led to the urbanization of marginally stable valley slopes, and this
has coincided with the apparent acceleration of landslide processes. Recent landslides on man-modified slopes were caused,
but not necessarily triggered, by heavy precipitation (antecedent moisture was a more critical factor than the amount of storm
rainfall). Because no important landslides on natural slopes in the same period were reported in the Caramanico area, a clear
distinction must be made between natural settings and those modified by man when determining rainfall thresholds for predictive
purposes. In recently urbanized mountainous environments, the thresholds used to assess landslide hazards should not be weighted
too heavily on old historical records of precipitation and associated mass movements. Instead, more weight ought to be given
to the period following the occurrence of any major anthropogenic and natural (e.g. high-magnitude earthquake) modification
of slope setting.
Received: 19 October 1996 · Accepted: 25 June 1997 相似文献
6.
Validation of Landslide Susceptibility Maps; Examples and Applications from a Case Study in Northern Spain 总被引:9,自引:3,他引:9
Remondo Juan González Alberto De Terán José Ramón Díaz Cendrero Antonio Fabbri Andrea Chung Chang-Jo F. 《Natural Hazards》2003,30(3):437-449
A procedure for validating landslide susceptibility maps wasapplied in a study area in northern Spain and the results obtained compared. Validationwas used to carry out sensitivity analysis for individual variables and combinationsof variables. The validity of different map-making methods was tested, as well as theutility of different types of Favourability Functions. The results obtained show thatvalidation is essential to determine the predictive value of susceptibility maps. Italso helps to better select the most suitable function and significant variables, thus improving the efficiency of the mapping process. Validation based on a temporal strategy makes it possible to derive hazard maps from susceptibility maps. 相似文献
7.
安康市滑坡崩塌频繁发生,对当地造成了不可估量的损失。以安康市地震小区划为依托,对当地滑坡地质灾害的易发性进行研究。在研究区进行野外踏勘和搜集资料的基础上,借助magis和arcgis平台强大的绘图、分析功能,运用层次分析法对滑坡灾害因子进行加权叠加计算,绘制滑坡灾害危险性区划图。区划结果分为四个等级:无危险区、低危险区、中危险区、高危险区。无危险区、低危险区滑坡灾害易发性较低,为适宜城市规划和项目实施工作地带,中危险区、高危险区则要加以治理以减少滑坡地质灾害对居民生命和财产的威胁。 相似文献
8.
Landslide risk assessment using concepts of danger pixels and fuzzy set theory in Darjeeling Himalayas 总被引:3,自引:1,他引:3
Landslide risk assessment (LRA) is a key component of landslide studies. The landslide risk can be defined as the potential
for adverse consequences or loss to human population and property due to the occurrence of landslides. The LRA can be regional
or site-specific in nature and is an important information for planning various developmental activities in the area. LRA
is considered as a function of landslide potential (LP) and resource damage potential (RDP). The LP and RDP are typically
characterized by the landslide susceptibility zonation map and the resource map (i.e., land use land cover map) of the area,
respectively. Development of approaches for LRA has always been a challenge. In the present study, two approaches for LRA,
one based on the concept of danger pixels and the other based on fuzzy set theory, have been developed and implemented to
generate LRA maps of Darjeeling Himalayas, India. The LRA map based on the first approach indicates that 1,015 pixels of habitation
and 921 pixels of road section are under risk due to landslides. The LRA map derived from fuzzy set theory based approach
shows that a part of habitat area (2,496 pixels) is under very high risk due to landslides. Also, another part of habitat
area and a portion of road network (7,204 pixels) are under high risk due to landslides. Thus, LRA map based on the concept
of danger pixels gives the pixels under different resource categories at risk due to landslides whereas the LRA map based
on the concept of fuzzy set theory further refines this result by defining the degree of severity of risk to these categories
by putting these into high and low risk zones. Hence, the landslide risk assessment study carried out using two approaches
in this paper can be considered in cohesion for assessing the risks due to landslides in a region. 相似文献
9.
A risk analysis is developed for a test site located in the area north of Lisbon using a scenario of a temporary interruption
of the motorway A9 due to a landslide of rotational or translational type. Landslide susceptibility is assessed at the regional
scale independently for rotational and translational slides, comparing the landslide distribution with a set of assumed independent
landslide predisposing factors. Susceptibility models are validated and classified through the computation of prediction rate
curves based on the temporal partition of the landslide data sets. Landslide hazard maps are based on a scenario of future
landslide occurrence for the next 27 years. These maps allow the definition of two critical areas on the motorway A9 with
regards to landslide susceptibility. Direct costs associated with both critical spots are assessed taking into account the
probable affected area of the motorway, and the reconstruction costs. Indirect costs derived from the traffic interruption
are evaluated considering the alternatives paths to the motorway, and include costs resulting from: (1) additional fuel consumption;
(2) decrease in tollgate income; and (3) loss of productive time. Results show that indirect costs may be 24 to 43 times higher
than direct costs, assuming a temporary interruption of the motorway for 6 months. 相似文献
10.
Regional hydrological thresholds for landslides and floods in the Tiber River Basin (central Italy) 总被引:11,自引:0,他引:11
The definition of landslide warning thresholds, based on the analysis of hydrological data, is proposed. In the Tiber River
Basin of central Italy historical information on landslides and floods, for the period 1918–1990, was available from a nationwide
bibliographical and archive inventory on geohydrological catastrophes. Hydrological data were obtained from mean daily discharge
records at various gauging stations within the basin. Several hundred hydrological events, broadly defined as a series of
consecutive days having mean daily discharge exceeding a predefined value, were identified. Hydrological parameters obtained
from the discharge records were used to rank the events according to their probability to trigger mass movements or inundations
and to define regional thresholds for the occurrence of landslides and floods. The proposed approach, not lacking limitations,
has conceptual and operational advantages, among which is the possibility of using historical information on geohydrological
catastrophes.
Received: 20 November 1996 · Accepted: 25 June 1997 相似文献
11.
Landslide susceptibility mapping: A comparison of logistic regression and neural networks methods in a medium scale study, Hendek region (Turkey) 总被引:36,自引:0,他引:36
Landslide susceptibility mapping is one of the most critical issues in Turkey. At present, geotechnical models appear to be useful only in areas of limited extent, because it is difficult to collect geotechnical data with appropriate resolution over larger regions. In addition, many of the physical variables that are necessary for running these models are not usually available, and their acquisition is often very costly. Conversely, statistical approaches are currently pursued to assess landslide hazard over large regions. However, these approaches cannot effectively model complicated landslide hazard problems, since there is a non-linear relationship between nature-based problems and their triggering factors. Most of the statistical methods are distribution-based and cannot handle multisource data that are commonly collected from nature. In this respect, logistic regression and neural networks provide the potential to overcome drawbacks and to satisfy more rigorous landslide susceptibility mapping requirements. In the Hendek region of Turkey, a segment of natural gas pipeline was damaged due to landslide. Re-routing of the pipeline is planned but it requires preparation of landslide susceptibility map. For this purpose, logistic regression analysis and neural networks are applied to prepare landslide susceptibility map of the problematic segment of the pipeline. At the end, comparative analysis is conducted on the strengths and weaknesses of both techniques. Based on the higher percentages of landslide bodies predicted in very high and high landslide susceptibility zones, and compatibility between field observations and the important factors obtained in the analyses, the result found by neural network is more realistic. 相似文献
12.
A shallow landslide erosion and sediment yield component, applicable at the basin scale, has been incorporated into the physically
based, spatially distributed, hydrological and sediment transport modelling system, SHETRAN. The component determines when
and where landslides occur in a basin in response to time-varying rainfall and snowmelt, the volume of material eroded and
released for onward transport, and the impact on basin sediment yield. Derived relationships are used to link the SHETRAN
grid resolution (up to 1 km), at which the basin hydrology and final sediment yield is modelled, to a subgrid resolution (typically
around 10–100 m) at which landslide occurrence and erosion is modelled. The subgrid discretization, landslide susceptibility
and potential landslide impact are determined in advance using a geographic information system (GIS), with SHETRAN then providing
information on temporal variation in the factors controlling landsliding. The ability to simulate landslide sediment yield
is demonstrated by a hypothetical application based on a catchment in Scotland.
Received: 30 October 1996 · Accepted: 25 June 1997 相似文献
13.
Field variability of landslide model parameters 总被引:4,自引:1,他引:4
A data set of parameters (slope, soil depth and soil shear strength) relevant to spatially distributed modelling of shallow
landslides triggered by rain and snowmelt events was determined from field measurements in 250 grid elements of dimensions
25 m (downslope)×10 m (across slope) in an area of 250 m×250 m on a hillslope in Scotland. These data provide an unusually
detailed basis for the evaluation of spatial variability and uncertainty in model parameterisation. The variations in slope
and soil strength are represented adequately by normal distributions; a Weibull distribution is suggested for the soil depth
data. The factor of safety calculated at each point in the grid was shown partially to identify observed landslides, with
a number of false predictions of occurrence. Trend analysis and semivariogram analysis of the data set suggest that the use
of kriging could improve upon this approach to landslide prediction by providing areal estimates of parameters at the grid
element scale with associated error bounds.
Received: 30 October 1996 · Accepted: 25 June 1997 相似文献
14.
Hydrogeological and geotechnical assessments of the Kadifekale landslide area, İzmir, Turkey 总被引:1,自引:0,他引:1
The study area is located in the south of İzmir city centre in an area built without planning permission or any overall city
plan. In this area, a number of mass movements occurred in the past and the region is still an active landslide field at present.
The real sliding factor is geological structure, which is made up of hard volcanic rocks overlying soft Neogene clayey soils,
and forms a typical structure prone to sliding. Unplanned human activities change the hydrogeological and geotechnical stabilities
of the geological formations in a negative way. Rain and water leaking either directly from the mains or septic holes infiltrate
into the ground and act as one of the factors in causing landslides. It is clearly shown that the irregular urbanization in
and around Kadifekale is one of the factors contributing to the landslides in the area. To prevent the occurrence of landslides
in the study area an effective surface and under ground drainage should be established. Rain and wastewater should be removed
from the area by separate systems. Slopes should be reduced, water-loving trees should be planted and construction of high
rise buildings should be avoided.
Received: 12 December 1997 · Accepted: 4 April 2000 相似文献
15.
Magnetic susceptibility measurements were conducted on 24 vibrocores obtained from an area located off the northeastern coast of Lantau Island in Hong Kong. High intensities of magnetic susceptibility were detected in the uppermost sections of the majority of the cores. Several magnetic parameters measured for one of the cores suggest that the variations in the magnetic characteristics over depth are mainly due to varying concentrations of the magnetic minerals. Since a strong correlation has been found between magnetic susceptibility and the heavy metals Pb, Cu, Zn and Cr, an anthropogenic contamination origin is thought to be the cause. The present study shows that magnetic susceptibility is a fast, inexpensive and non-destructive method for the detection and mapping of contaminated sediments. Received: 12 August 1997 · Accepted: 18 November 1997 相似文献
16.
V. D. Mats O. M. Khlystov M. De Batist S. Ceramicola T. K. Lomonosova A. Klimansky 《International Journal of Earth Sciences》2000,89(2):229-250
New high-resolution seismic reflection data from the central part of Lake Baikal provide new insight into the structure and
stratigraphy of Academician Ridge, a large intra-rift accommodation zone separating the Central and North Baikal basins. Four
seismic packages are distinguished above the basement: a thin top-of-basement unit; seismic-stratigraphic unit X; seismic-stratigraphic
unit A; and seismic-stratigraphic unit B. Units A and B were cored on selected key locations. The four packages are correlated
with a series of deposits exposed on the nearby western shores: the Ularyar Sequence (Oligocene); the Tagay Sequence (Lower
to Middle Miocene); the Sasa Sequence (Upper Miocene to Lower Pliocene); the Kharantsy Sequence (Upper Pliocene); and the
Nyurga Sequence (Lower Pleistocene). Based on stratal relationships, sedimentary geometries, distribution patterns and principal
morphostructural elements – both onshore and offshore – we propose a new palaeogeographic evolution model for the area. In
this model progressive tectonic subsidence of the Baikal basins and successive pulses of uplift of various segments of the
rift margins lead to: (a) formation of the ridge as a structural and morphological feature separating the Central and North
Baikal basins during the Middle to Late Miocene; (b) gradual flooding of the main parts of the ridge and establishment of
a lacustrine connection between the two rift basins during the Late Miocene; and (c) total submergence of the top parts of
the crest of the ridge during the latest Pleistocene. This new model helps to better constrain numerous phases in the structural
evolution of the Baikal Rift, in which the Academician Ridge as an accommodation zone plays a crucial role.
Received: 26 November 1999 / Accepted: 12 March 2000 相似文献
17.
Chromium and manganese zoning in pelitic garnet and kyanite: Spiral,overprint, and oscillatory (?) zoning patterns and the role of growth rate 总被引:4,自引:0,他引:4
X‐ray composition maps and quantitative analyses for Mn, Ca and Cr have been made for six pelitic and calc‐pelitic garnet crystals and Al, Fe and Cr analyses maps have been made for two kyanite crystals, from lower and mid/upper amphibolite facies rocks from the Grenville Province of western Labrador, using an electron microprobe analyser and a laser ablation ICP‐MS. Garnet with spiral (‘snowball’) internal fabrics (Si) has spiral zoning in major elements, implying that growth was concentrated in discrete regions of the crystal at any one time (spiral zoning). Cr zoning is parallel to Si in low amphibolite facies garnet with both straight and spiral internal fabrics, indicating that the garnet overprinted a fabric defined by Cr‐rich (mica±chlorite±epidote) and Cr‐poor (quartz±plagioclase) layers during growth (overprint zoning) and that Cr was effectively immobile. In contrast, in mid/upper amphibolite facies garnet porphyroblasts lacking Si, Cr zoning is concentric, implying that Cr diffusion occurred. Cr zoning in kyanite porphyroblasts appears superficially similar to oscillatory zoning, with up to three or four annuli of Cr enrichment and/or depletion present in a single grain. However, the variable width, continuity, Cr concentration and local bifurcation of individual annuli suggest that an origin by overprint zoning may be more likely. The results of this study explain previously observed nonsystematic Cr zoning in garnet and irregular partitioning of Cr between coexisting metamorphic mineral pairs. In addition, this study points to the important role of crystal growth rate in determining the presence or absence of inclusions and the type of zoning exhibited by both major and trace elements. During fast growth, inclusions are preferentially incorporated into the growing porphyroblast and slow diffusing elements such as Cr are effectively immobile, whereas during slow growth, inclusions are not generally included in the porphyroblast and Cr zoning is concentric. 相似文献
18.
Heavy metals in freshly deposited sediments of the Gomati River (a tributary of the Ganga River): effects of human activities 总被引:10,自引:0,他引:10
The concentrations of various metals (Cr, Cu, Co, Fe, Mn, Ni, Pb, Zn, and Cd) were determined in recently deposited surface
sediments of the Gomati River in the Lucknow urban area. Markedly elevated concentrations (milligrams per kilogram) of some
of the metals, Cd (0.26–3.62), Cu (33–147), Ni (45–86), Pb (25–77), and Zn (90–389) were observed. Profiles of these metals
across the Lucknow urban stretch show a progressive downstream increase due to additions from 4 major drainage networks discharging
the urban effluents into the river. The degree of metal contamination is compared with the local background and global standards.
The geoaccumulation index order for the river sediments is Cd>Zn>Cu>Cr>Pb. Significant correlations were observed between
Cr and Zn, Cr and Cu, Cu and Zn and total sediment carbon with Cr and Zn. This study reveals that the urbanization process
is associated with higher concentrations of heavy metals such as Cd, Cu, Cr, Pb, and Zn in the Gomati River sediments. To
keep the river clean for the future, it is strongly recommended that urban effluents should not be overlooked before their
discharge into the river.
Received: 16 February 1996 · Accepted: 29 February 1996 相似文献
19.
Landslide susceptibility mapping using GIS and digital photogrammetric techniques: a case study from Ardesen (NE-Turkey) 总被引:3,自引:3,他引:3
Ardesen is a settlement area which has been significantly damaged by frequent landslides which are caused by severe rainfalls
and result in many casualties. In this study a landslide susceptibility map of Ardesen was prepared using the Analytical Hierarchy
Process (AHP) with the help of Geographical Information Systems (GIS) and Digital Photogrametry Techniques (DPT). A landslide
inventory, lithology–weathering, slope, aspect, land cover, shear strength, distance to the river, stream density and distance
to the road thematics data layers were used to create the map. These layer maps are produced using field, laboratory and office
studies, and by the use of GIS and DPT. The landslide inventory map is also required to determine the relationship between
these maps and landslides using DPT. In the study field in the Hemsindere Formation there are units that have different weathering
classes, and this significantly affects the shear strength of the soil. In this study, shear strength values are calculated
in great detail with field and laboratory studies and an additional layer is evaluated with the help of the stability studies
used to produce the landslide susceptibility map. Finally, an overlay analysis is carried out by evaluating the layers obtained
according to their weight, and the landslide susceptibility map is produced. The study area was classified into five classes
of relative landslide susceptibility, namely, very low, low, moderate, high, and very high. Based on this analysis, the area
and percentage distribution of landslide susceptibility degrees were calculated and it was found that 28% of the region is
under the threat of landslides. Furthermore, the landslide susceptibility map and the landslide inventory map were compared
to determine whether the models produced are compatible with the real situation resulting in compatibility rate of 84%. The
total numbers of dwellings in the study area were determined one by one using aerial photos and it was found that 30% of the
houses, with a total occupancy of approximately 2,300 people, have a high or very high risk of being affected by landslides. 相似文献
20.
The study brings new information concerning a large slope deformation in the northern part of the Silesian Beskydy Mountains
in the territory of the Czech Republic. The studied area is a large-scale transformation of the forefront of a flysch nappe
formed especially by rigid sandstones upon a plastic underlying nappe. As a consequence of the vertical contact of mechanically
different formations and depositing conditions of rocks and tectonics on the nappe forefront, several generations of deep-seated
slope deformations occurred accompanied by shallow landslides in the historic period. Structural measurement and geophysical
sounding proved prevailing lateral spreading in the upper parts of the slopes as well as the occurrence of rotational landslides
whose landslide scarps overlap with the line of overthrust of the Godula Nappe on the Těšín Nappe. Radiocarbon dating determined
the period of the occurrence of rotational landslides as falling into the Subboreal up to Subatlantic. 相似文献