Flow Slides Research Articles

A model for geotechnical analysis of flow slides and debris flows

Flow slides and debris flows incorporate a broad range of sediment–fluid mixtures that are intermediate between dry rock avalanches and hyperconcentrated flows. Following a comprehensive review of some existing analytical approaches to debris flow runout analysis, a new analytical model based on energy conservation has been formulated. The new analytical model was developed to deepen the understanding of fundamental aspects in modeling of granular flows and to improve the geotechnical mobility analysis of flow slides and debris flows. The Lagrangian finite difference method was used to solve the governing equations. The model and numerical scheme have been tested against analytical solutions and experiments of granular flows with simplified geometries for sliding mass and basal topography. Results of granular flow simulations indicate that the model based on energy conservation performs well and is robust. The model can be used for geotechnical analysis of a wide range of dense granular flows, such as flow slides and debris flows.

Quantitative landslide hazard assessment along a transportation corridor in southern India

A quantitative model for landslide hazard assessment on natural slopes is presented for a transportation corridor of the Nilgiri Hills in southern India. The data required for the hazard assessment were mostly obtained from historical records. For the hazard modeling, a landslide inventory map was prepared from technical reports and maintenance records for a road and a railroad, available for a 21 year period from 1987 to 2007. Most landslides are shallow translational debris slides and debris flow slides triggered by rainfall. On natural slopes landslides occurred as first-time failures. A logistic regression model was used to determine the spatial probability of landslides for each pixel by taking the source area of the existing landslides as dependent, and slope angle, aspect, regolith thickness and land use as independent variables. The temporal probability of landslides was estimated indirectly using the exceedance probability of the rainfall threshold required to trigger landslides for the first time on natural slopes. The probability of landslide size was estimated as frequency percentage of landslide volume, a proxy for landslide magnitude, and the percentage values were then expressed as probability. By assuming independence among the three probabilities, a quantitative estimate of a landslide hazard was obtained as the joint probability of landslide volume, of landslide occurrence in an established time period and of spatial probability of a landslide initiation. The models were validated using the rainfall and landslide events that occurred during 2008 and 2009. Total 12 specific landslide hazard maps were generated considering six time periods (1, 3, 5, 15, 25 and 50 years), and two landslide volumes (volume exceeding 1000 m 3 and 10,000 m 3).

OPHIOLITES FROM THE GRAMMOS-ARRENES AREA, NORTHERN GREECE: GEOLOGICAL, PALEONTOLOGICAL AND GEOCHEMICAL DATA

The Grammos-Arrenes ophiolites crop out between the Pindos Flysch to the East and the Meso-Hellenic basin to the West and represent the northernmost exposure of the Pindos Ophiolite belt in Greece. Field work and sampling on key outcrops of the Sub-ophiolitic Melange provided new data on the oceanization age and on the geochemistry of the effusive products. The basalts samples show a N-MOR affinity and are associated with latest Bajocian-early Bathonian radiolarian cherts. Emplacement of the ophiolites onto the continental margin is preceded by mass flow deposition of ophiolitic material in the basins facing the advancing ophiolitic nappe. Ophiolite-bearing debris flow deposits and slide blocks are recognized in the Early Cretaceous deep water sediments of the Beotian Unit and in the upper portion of the Tertiary Pindos Flysch. The intercalations of ophiolitic material in the Beotian Flysch first, and in the Pindos Flysch, later, are interpreted as the forerunners of the Ophiolitic Nappe which derived from the Vardar Ocean to the east, and was emplaced westwards onto the Adria continental margin. The collected data allow consolidating the constraints for the timing and mechanism of ophiolite emplacement in the Pindos-Grammos area. In addition, taking into consideration the geometry of the tectonic stack in the Grammos-Arrenes area and the ages of the involved sedimentary deposits it is possible to reconstruct a geodynamic history comparable to that of the other zones studied along the Dinaric-Hellenic Chain.

Residual Strength of Liquefied Sand Measured in a Ring Shear Device

Abstract Earthquake-induced liquefaction flow slides have resulted in loss of life and major damage at many sites around the world. In order to better understand the mechanics of such slides, it is necessary to quantify the residual shearing strength of the liquefied soil. Small-scale stress-controlled experiments suggest that this residual strength is not a constant, but that liquefied sand can be modeled as a highly viscous stress-thinning fluid, whose resistance varies with the velocity of flow. We present results obtained with a ring shear device designed specifically to measure the large-displacement post-liquefaction residual strength of sands under strain-controlled conditions. Residual strength of a fine uniform sand was measured for a range of relative densities (Dr) from 19 % to 36 % at four different shear-strain rates, varying from 11 to 44 s−1 representative of flow slide velocities. Measurements show that the strain-rate-dependent Herschel–Bulkley model for stress-thinning fluids applies to the liquefied sand, with resistance increasing as strain rate increases, but suggest that at relative densities higher than perhaps 50 %, relative density dominates, and residual strength can be approximated as a constant.

Propagation of seismic waves through liquefied soils

ARTICLE IN PRESS Soil Dynamics and Earthquake Engineering 30 (2010) 236–257 Contents lists available at ScienceDirect Soil Dynamics and Earthquake Engineering journal homepage: www.elsevier.com/locate/soildyn Propagation of seismic waves through liquefied soils Mahdi Taiebat a, A , Boris Jeremic b , Yannis F. Dafalias b,c , Amir M. Kaynia d , Zhao Cheng e a Department of Civil Engineering, University of British Columbia, Vancouver, BC, Canada V6T 1Z4 Department of Civil and Environmental Engineering, University of California, Davis, CA 95616, USA Department of Mechanics, National Technical University of Athens, Zographou 15780, Hellas d Norwegian Geotechnical Institute, P.O. Box 3930 Ullevaal Stadion, N-0806 Oslo, Norway e Earth Mechanics Inc., Oakland, CA 94621, USA b c a r t i c l e in f o a b s t r a c t Article history: Received 23 March 2009 Received in revised form 21 November 2009 Accepted 23 November 2009 To predict the earthquake response of saturated porous media it is essential to correctly simulate the generation, redistribution, and dissipation of excess pore water pressure during and after earthquake shaking. To this end, a reliable numerical tool requires a dynamic, fully coupled formulation for solid– fluid interaction and a versatile constitutive model. Presented in this paper is a 3D finite element framework that has been developed and utilized for this purpose. The framework employs fully coupled dynamic field equations with a u–p–U formulation for simulation of pore fluid and solid skeleton interaction and a SANISAND constitutive model for response of solid skeleton. After a detailed verification and validation of the formulation and implementation of the developed numerical tool, it is employed in the seismic response of saturated porous media. The study includes examination of the mechanism of propagation of the earthquake-induced shear waves and liquefaction phenomenon in uniform and layered profiles of saturated sand deposits. & 2009 Elsevier Ltd. All rights reserved. Keywords: Numerical analysis Wave propagation Earthquake Liquefaction Constitutive modeling 1. Introduction Performance-based design (PBD) of geotechnical structures is gaining popularity in professional practice and is fostering research in the academic community. PBD relies heavily on modeling and simulation tools. One of the challenges in PBD of geotechnical and geophysical problems is analysis of dynamic transient phenomena in fluid-saturated porous media and, in particular, modeling and simulations of seismic wave propaga- tion. This subject, which can be related to liquefaction, continues to challenge engineering research and practice. In addition, lateral movement of sloping ground as a result of pore pressure generation poses other challenges in PBD. Pore pressure generation phenomenon commonly occurs in loose to medium dense sands that are fully saturated and may induce two related phenomena: the flow liquefaction which leads to flow slides and the cyclic mobility which leads to lateral spreads. Pore pressure generation phenomenon commonly occurs in loose to medium dense sands that are fully saturated and may induce two related phenomena: the flow lique- faction that leads to flow slides and the cyclic mobility that leads to lateral spreads. Flow liquefaction occurs when shear stresses required for static equilibrium exceed residual shear A Corresponding author. Tel.: + 1 604 822 3279; fax: + 1 604 822 6901. E-mail address: mtaiebat@civil.ubc.ca (M. Taiebat). 0267-7261/$ - see front matter & 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.soildyn.2009.11.003 strength, as opposed to liquefaction, which implies a zero effective stress. In this phenomenon an earthquake brings soil to the point of instability, and deformations are driven by static stresses. The associated failure occurs rapidly with little warning and produces large deformations. On the other hand, cyclic mobility occurs when shear stresses required for static equili- brium are less than residual shear strength. These deformations are driven by dynamic stresses, occur incrementally, and can be large or small [1]. Accumulation of permanent deformations, degradation of soil moduli, increase of hysteretic damping, and change of soil fabric as a function of imposed cyclic shear strains require advanced models and implementations that are tricky but doable. In order to systematically investigate this subject it is necessary to predict the generation, redistribution, and dissipa- tion of excess pore pressures during and after earthquake shaking and their impact on the transmitted waves. A fundamental approach requires a dynamic coupled stress-field analysis. Fully coupled transient response of solid–pore fluid interaction and constitutive behavior of the soil skeletonsolid skeleton play equally important roles in successful numerical simulation of response in saturated granular soil medium. The mechanical model of this interaction, when combined with a suitable constitutive description of the solid phase and with efficient, discrete, computation procedures, allows most transient and static problems involving deformations to be properly modeled and accurately simulated.

Numerical modelling of the motion of rapid, flow-like landslides for hazard assessment

Computer methods for analysis of stresses, strains and displacements of soil structures have made spectacular advances in recent years. Now, a new field of analysis with substantial practical significance is opening up. This is the quantitative analysis of motion of rapidly moving masses of earth and fragmented rock in landslides such as debris avalanches, debris flows, flow slides and rock avalanches. The new methods accept an unstable body of material on the slope as input (the “landslide source”) and map its propagation down the slope in terms of flow depth and velocity. This allows outlining the extent of potential hazard areas and the distribution of hazard intensity parameters within them as needed for detailed hazard mapping, estimation of risks and design of remedial measures such as deflecting walls, dykes or barriers. Two advanced numerical solutions based on integrated “shallow-flow” Lagrangian theory of unsteady flow of non-Newtonian fluid are described in terms of their theoretical background, assumptions regarding the type of flow and rheological characteristics, as well as examples of a variety of results. The two models are the pseudo-three dimensional code DAN and its extension into three dimensions, DAN3D. Both codes have the following main capabilities: 1) Open rheological kernel, allowing the choice of a variety of rheological relationships to suit a particular character of the moving mass; 2) ability to change rheology during the flow; 3) non-hydrostatic, anisotropic internal stress distribution controlled by longitudinal strain; and 4) ability to entrain material during the flow. Both codes are highly efficient and both produce similar results when applied to the same example.

THE OPHIOLITE-BEARING MÉLANGE IN THE EARLY TERTIARY PINDOS FLYSCH OF ETOLIA (CENTRAL GREECE)

In Etolia (Central Greece), west of the Parnassus/Vardoussia units, the Pindos succession crops out, with its higher formation: the Pindos Flysch. In its upper portion levels of debris flow deposits and slide blocks (olistostromes and olistoliths) contain ophiolitic material with fragments derived from the Parnassus/ Vardussia formations. This ophiolitic material consists of serpentinites, basalts of WPB, E- and N-MOR affinity, and radiolarian cherts of Middle-Late Triassic and Middle-Late Jurassic age. Petrologic and biostratigraphic analyses confirm that the melange has the same features of the sub-ophiolitic melanges present at the base of the ophiolitic masses in Greece. Linked to the flysch, with contacts of unclear nature, a rhyolites body of Middle Triassic age indicates the continental nature of the Pindos Basin. In fact, here, as all over the Albanian-Greek section of the Dinarides, no record of an oceanic area in the central portion of the Dinarides exists: the Parnassus and Vardoussia units were directly thrust onto the Pindos Basin. The intercalations of ophiolitic and continent-derived material in the flysch, are interpreted as the forerunners of the Ophiolitie Nappe which, coming from the Vardar Ocean located to the east, reached during the Eocene the Pindos Basin.

Behaviors of pile foundation with surface non-liquefaction layer induced by liquefaction ground flow slide

1964年の新潟地震以来，液状化時の地盤の流動に起因する橋梁や建物の杭基礎の破壊事例が多数報告され，被害メカニズムや対策工についての様々な調査研究が行われてきた。実際に被害が発生した地盤の多くは，植生や舗装，路盤処理または年代効果や不飽和サクションによってある程度固結した非液状化層で覆われている。このような透水性が小さく液状化流動時にも剛性を失わない地表面非液状化層は液状化の継続時間を拡大するのみならず，杭基礎に作用する外力を増大させる直接的な効果があると考えられる。しかしながら，液状化時の地盤流動による杭基礎に作用する地盤外力，特に地表面非液状化層の影響はこれまで十分に検討されていないのが現状である。本研究では，杭基礎，液状化地盤および地表面非液状化層との相互作用に着目し，液状化傾斜地盤における地盤流動によって生じた杭基礎に作用する地盤外力挙動を明らかにすることを目的とし3タイプの模型地盤に対して1g場振動台実験を実施した。その結果，液状化流動中の杭基礎に作用する地盤外力は，地表面非液状化層の存在により液状化流動地盤のサイクリックモビリティーが助長され，増大する傾向にあることがわかった。

Simplified models of spreading flow of dry granular material

Shallow-flow integrated numerical models of landslide and avalanche motion have recently experienced rapid development. An important aspect of model development is verification, to show that models are correct and reasonably robust in their application of basic physical principles. Most existing models have been verified against controlled laboratory experiments using dry granular material. In this article, it is shown that spreading flows such as the “dam-break” problem in frictional material pose problems for shallow-flow analysis. A series of dam-break laboratory experiments have been carried out with several different slope angles and bed materials. A model was then applied using four alternative assumptions regarding the distribution of earth pressure in the sliding mass. It was shown that assumptions commonly used in previous work produce very substantial errors (up to 200%) when applied to the prediction of dam-break runout in material with both internal and basal friction. A new model is proposed based on a simple modification of the well-known SH assumptions. This new model provides excellent agreement with experimental results, both for shallow avalanches and spreading flows. It represents a means to greatly expand the applicability of shallow-flow models to real landslide problems involving spreading flow, such as flow slides.

Numerical simulation of Al 2O 3 deposition at a nozzle during continuous casting

The effects of various factors, such as argon flow rate and slide gate opening ratio, on the alumina deposition rate were researched by the numerical simulation method. The pressure in the nozzle is significantly affected by argon flow rate and slide gate opening ratio. To keep positive pressure in the nozzle, the argon flow rate should be increased with a decrease in slide gate opening ratio. The effect of argon flow rate on the alumina deposition rate depends on the condition of opening ratio or casting speed. The effect of increasing the argon flow rate on the deposition rate is not obvious when the opening ratio is small. The Al 2O 3 deposition rate decreases significantly with an increase in argon flow rate when the argon flow rate is low, but it decreases slowly when the argon flow rate reaches a certain value. The alumina deposition rate is linear with alumina content at different slide gate opening ratios and argon flow rates. The observed thickness of the deposition layer at the bottom and outlet of a real clogged nozzle is almost equal to the result of the numerical simulation.

Numerical Modelling of the Dynamics of Debris Flows and Rock Avalanches

AbstractPrediction of velocity and travel distance of potential rapid landslides such as debris flows, debris avalanches, flow slides and rock avalanches is useful for quantitative hazard and risk assessment. This article describes some methods that are becoming available for practical use. The proposed approach uses calibration of relatively simple numerical landslide dynamics models against observed behaviour of real landslide events. Two example cases of runout back‐analyses, selected from a recent International Benchmarking Exercise conducted in Hong Kong, are presented.

Seismic liquefaction, lateral spreading, and flow slides: a numerical investigation into void redistribution

Experience from past earthquakes indicates that seismically induced large lateral spreads and flow slides in alluvial sand deposits have taken place in coastal and river areas in many parts of the world. The ground slope in these slides was often not very steep, gentler than a few percent. Recent research indicates that the presence of low-permeability silt or clay sublayers within the sand deposits is responsible for this behaviour. Such layers form a barrier to upward flow of water associated with earthquake-generated pore pressures. This causes an accumulation of pore water at the base of the layers, resulting in greatly reduced strength and possible slope instability. This paper uses an effective stress coupled stress-flow dynamic analyses procedure to demonstrate the effects of a low-permeability barrier layer on ground deformations from an earthquake event. The analyses show that an expansion zone develops at the base of barrier layers in stratified soil deposits under seismic loading which can greatly reduce shear strength and result in large deformations and flow failure. Without such a layer or layers, the slope may undergo significant displacements, but not a flow slide. Slopes with a barrier layer can be stabilized by drains.Key words: liquefaction, lateral spreads, stratification, flow failure, dynamic analysis, UBCSAND model, drain.

GIS analysis to assess landslide susceptibility in a fluvial basin of NW Sicily (Italy)

Landslide hazard assessment, effected by means of geostatistical methods, is based on the analysis of the relationships between landslides and the spatial distributions of some instability factors. Frequently such analyses are based on landslide inventories in which each record represents the entire unstable area and is managed as a single instability landform. In this research, landslide susceptibility is evaluated through the study of a variety of instability landforms: landslides, scarps and areas uphill from crown . The instability factors selected were: bedrock lithology, steepness, topographic wetness index and stream power index. The instability landform densities computed for all the factors, which were arranged in Unique Condition Unit, allowed us to derive a total of three prediction images for each landslide typology. The role of the instability factors and the effects generated by the use of different landforms were analyzed by means of: a) bivariate analysis of the relationships between factors and landslide density; b) predictive power validations of the prediction images, based on a random partition strategy. The test area was the Iato River Basin (North-Western Sicily), whose slopes are moderately involved in flow and rotational slide landslides (219 and 28, respectively). The area is mainly made up of the following complexes: Numidian Flysch clays (19%, 1%), Terravecchia sandy clays (5%, 1%), Terravecchia clayey sands (3%, 0.3%) and San Cipirello marly clays (9%, 0%). The steepness parameter shows the highest landslide density in the [11–19°] class for both the typologies (8%, 1%), even if the density distributions for rotational slides are right-asymmetric and right-shifted. We obtained significant differences in shape when we used different instability landforms. Unlike scarps and areas uphill from crowns, landslide areas produce left-asymmetric and left-shifted density distributions for both the typologies. As far as the topographic wetness index is concerned, much more pronounced differences were detected among the instability landforms of rotational slides. In contrast, the flow landslides produce normal-like density distributions. The latter and the rotational slide landslide areas produce the highest density values in the class [5.5–6.7], despite an abrupt decreasing trend starting from the first class [3.2–4.4], which is generated by the density values of the rotational slide scarps and areas uphill from crowns. The stream power index at the foot of the slopes, which was automatically derived using a GIS-procedure, shows a positive correlation with the landslide densities marked by the maximum classes: [4.8–6.0] for flows, and [6.0–7.2] for rotational slides. The validation procedure results confirmed that the choice of instability landform influences the results of the susceptibility analysis. Furthermore, the validation procedure indicates that: a) the predictive models are generally satisfactory; b) scarps and zones uphill from crown areas are the most diagnostically unstable landforms, for flow and rotational slide landslides respectively.

Stabilisation of old lignite pit dumps in Eastern Germany

The lignite workings in the former German Democratic Republic have left many residual holes of sometimes colossal scale. The artificial or natural flooding of these 50–70 m deep holes causes serious stability problems in sand slopes, and already fatalities have been reported as a result of the sudden initiation of flow slides. The paper describes the soil mechanics of the flow slides, which endanger the edge of the holes, and the measures taken to stabilise the slopes.

Flow deformation of liquefied sand under constant shear load and its application to analysis of flow slide of infinite slope

This paper intended to evaluate the behavior of saturated sand and sloped ground subjected to flow failure with seepage of pore water in the ground after earthquake and the resultant liquefaction. Triaxial compression tests of sand with constant deviator stress but changing of pore pressure and volume of the specimens were conducted in this study. It was revealed that the relation between the volume change and the amount of shear strain during deformation depended on the initial density of the sand but it did not much depend on shear stress and initial confining stress levels. Based on this test results and numerical analysis of the seepage of pore water in liquefied ground, a methodology was proposed to predict the deformation of inclined ground due to liquefaction.

Catastrophe revisited ? disastrous flow failures of mine and municipal solid waste

Catastrophic flow failures have occurred with alarming frequency in mine tailings dams and dumps of discards and other mine waste. In recent years, catastrophic flow failures have also occurred in dumps of municipal solid waste and even in what were intended to be carefully controlled and well-engineered landfills. Apart from the environmental devastation caused by these flows, they are also dangerous to human life and society. Examples include the Buffalo Creek disaster in the USA in 1972 (Vick, Planning, Design and Analysis of Tailings Dams, Wiley, 1983) that killed 118 people, made 4000 homeless and destroyed 50 million US dollars worth of property and facilities. The flow slide that occurred in the Umraniye– Hekimbasi refuse dump in Turkey in 1993 (Kocasoy and Curi, Waste Management and Research, 13, 1995, 305) killed 39 people, destroying their homes in the process. This paper will briefly review some of the more notable flow slides in waste materials, analyzing conditions necessary for a flow failure to occur and pointing to ways of preventing this type of failure by a combination of sound design and operating procedures.

Numerical experiments of soil nails in loose fill slopes subjected to rainfall infiltration effects

Finite difference analyses were conducted to explore the possible behaviour of soil nails in loose fill slopes which were formed by strain-softening materials. Numerical models simulating a 20 m high 35° loose fill slope were set up. With the use of an undrained strain-softening soil model, the behaviour of a loose fill slope reinforced with soil nails subjected to rainfall infiltration was studied. Results indicated that soil nails together with a proper facing structure may reduce the deformation of a loose fill slope caused by rainfall infiltration and hence maintain the stability of the slope. Tensile forces in the soil nails were mobilised through the effective connections between the facing structure and the nail heads when a potential slide was being initiated. Through this mechanism, the development of a flow slide at shallow depths could be avoided by the pull out resistance between the soil and the nails at deeper locations of the slope. Results also showed that, if the soil nails were not connected to a facing structure or nail heads at the slope surface, a global failure mechanism involving the development of a flow slide could be observed, which was similar to that of a loose fill slope without soil nails.

A model for the analysis of rapid landslide motion across three-dimensional terrain

A new numerical model for the dynamic analysis of rapid flow slides, debris flows, and avalanches has been developed. The model is an extension of an earlier algorithm and is implemented using a numerical method adapted from smoothed particle hydrodynamics. Its features include (i) the ability to simulate flow across complex three-dimensional terrain; (ii) the ability to allow nonhydrostatic and anisotropic internal stress distributions, coupled with strain changes through frictional relationships; (iii) the ability to simulate material entrainment; (iv) a choice of different rheological kernels, including frictional, plastic, viscous, Bingham, and Voellmy; (v) a meshless solution, which eliminates problems with mesh distortion during long displacements; and (vi) highly efficient and simple operation. The model has been tested by analysing a series of laboratory flume experiments with granular materials, both on straight and curved paths. The model is capable of accurately predicting the margins of various curving flows using a single set of input parameters. A preliminary analysis of a real rock avalanche case history is also included.Key words: landslides, debris flows, rock avalanches, runout analysis, dynamic modelling, numerical methods.

Movimentos de vertente, análise de risco e ordenamento do território; o exemplo recente do fluxo deslizante de Armamar (Douro vinhateiro, Portugal)

No dia 3 de Janeiro de 2003, a Estrada Nacional222 que, pela margem esquerda do Douro, liga Peso da Régua à localidade de Pinhão, foi destruída ao Km 37 ±300m, numa extensão de cerca de 60 metros, em toda a sua largura, em consequência da movimentação newtoniana de materiais detríticos que estruturam os socalcos das vertentes adaptadas ao cultivo da vinha. Sem consequências ao nível da perda de vidas humanas, a contingência do desastre viria, contudo, a materializar-se pela destruição da referida estrada e de uma área significativa de vinha e da própria vertente, bem como pelos elevados custos a que obrigaram, por um lado, a reconstrução da estrada e, por outro lado, a correcção e estabilização da vertente. Os efeitos decorrentes deste desastre "natural" destacam-se também pelos elevados transtornos que impuseram à dinâmica socioeconómica da região. Tratando-se de acidentes que geralmente são induzidos pela intervenção humana na morfodinâmica das vertentes, este é apenas mais um exemplo, o mais recente, de instabilidade associada às vertentes do Douro Vinhateiro, pelo que a tomada de consciência para a gravidade do problema constitui, cada vez mais, um importante requi sito para o correcto ordenamento do espaço e para gestão dos recursos, em respeito para com as leis da Física .. . que são também as da Natureza.

Use of fuzzy relations to produce landslide susceptibility map of a landslide prone area (West Black Sea Region, Turkey)

Preparation of landslide susceptibility maps is important for engineering geologists and geomorphologists. However, due to complex nature of landslides, producing a reliable susceptibility map is not easy. For this reason, many procedures have been used to produce such maps. In this study, a new attempt is tried to produce landslide susceptibility map of a part of West Black Sea Region of Turkey. To obtain the fuzzy relations for producing the susceptibility map, a landslide inventory database is compiled by both field surveys and airphoto studies. A total of 266 landslides are identified in the study area, and dominant mode of failure is rotational slide while the other mode of failures are soil flow and shallow translational slide. The landslide inventory and the parameter maps are analyzed together using a computer program (FULLSA) developed in this study. The computer program utilizes the fuzzy relations and produces the landslide susceptibility map automatically. According to this map, 9.6% of the study area is classified as very high susceptibility, 10.3% as high susceptibility, 8.9% as moderate susceptibility, 27.5% as low susceptibility and 43.8% as very low susceptibility or nonsusceptible areas. The prediction performance of the susceptibility map is checked by considering actual landslides in the study area. For this purpose, strength of the relation ( r ij ) and the root mean square error (RMSE) values are calculated as 0.867 and 0.284, respectively. These values show that the produced landslide susceptibility map in the present study has a sufficient reliability. It is believed that the approach employed in this study mainly prevents the subjectivity sourced from the parameter selection and provides a support to improve the landslide susceptibility mapping studies.