The Skunk Hollow Landslide (located 1 mile north of Mantua, UT along US-89) was instrumented with an automated monitoring system to aid in the determination of the triggering mechanism of slow moving landslides. Data was transmitted wirelessly through telecommunications to allow year-round, real-time monitoring of the site. Measurements were recorded and analyzed for the first season of landslide movement (fall 2009 to spring 2010) to better understand the correlations between snowmelt and movement initiation. Based on the first year of data, it appears that the Skunk Hollow Landslide is controlled by water infiltrating into the slide mass through cracks and fissures. Snowmelt is a function of many meteorological variables and future years of observation will create a better understanding of the interaction of these variables with landslide initiation.

Thesis (M.S.)--Oregon State University, 2001. / Typescript (photocopy). Includes bibliographical references (leaves 71-73). Also available on the World Wide Web.

Thesis (M.S.)--Oregon State University, 2003. / Typescript (photocopy). Includes bibliographical references (leaves 99-101). Also available on the World Wide Web.

Thesis (M.S.)--University of Tennessee, Knoxville, 2002. / Title from title page screen (viewed Feb. 28, 2003). Thesis advisor: Eric Drumm. Document formatted into pages (v, 148 p. : ill. (some col.)). Vita. Includes bibliographical references (p. 27-29).

Thesis (Ph. D.)--Oregon State University, 1997. / Typescript (photocopy). Includes bibliographical references (leaves 173-179). Also available on the World Wide Web.

Smectite clay minerals are among the most common minerals in subduction zone megathrusts faults at shallow depth and in landslide decollements. Consequently, deformation processes at seismic slip rates (ca. 1 m/s) in smectites contribute to control the mechanics of megathrust earthquakes and landslide collapses. To investigate the deformation processes, rotary shear experiments on smectite-rich gouge layers (70/30 wt.% Ca-montmorillonite/opal) were performed. The experiments were conducted at ambient temperature and at 5 MPa normal stress. The gouges were sheared under vacuum (<0.001 mbar) and room humidity (i.e., water depleted) or in the presence of liquid water (i.e., water rich) conditions, at slip rates of 0.0003 <V <1.5 m/s and displacements of 0.1 <d <30 m. The temperature evolution with slip was measured with thermocouples and modelled numerically. Permeability of the gouge layer was measured with the pore pressure oscillation method prior to the rotary experiments. Before and after the experiments, the mineral and amorphous material content in wt.% were determined via quantitative X-ray powder diffraction and the microstructures investigated via scanning and transmission electron microscopy. The activation of deformation processes was strongly controlled by the water content of the gouge layers. Under water depleted conditions, grainsize reduction producing nanoparticles controlled the evolution of the friction coefficient f at all slip rates. Coseismic dynamic weakening (f = 0.2 - 0.3) occurred by combined thermal decomposition or melting (with decreasing water content) and pressurization of water released by dehydration of smectite interlayer. Under water rich conditions, grain size reduction was minor and development of nano-foliations occurred. At all slip rates, the friction coefficient rapidly decreased at the onset of slip. The large initial weakening (to f <0.15) was due to the presence of a film of water lubricating the surfaces of the sub-parallel smectite grains forming the nano-foliation in combination with shear-enhanced water pressurization. Then, friction coefficient evolved depending on the balance between dissipation of pore pressures, dehydration of smectite interlayer and thickening of the nano-foliation layers. At higher displacement and slip rates, sustained dynamic weakening was aided by vaporization of pore water. Expulsion of water determined a switch to deformation processes typical of water depleted conditions. In nature, the presence of liquid water in smectites has a lubricating effect, pressurizes the slipping zone and renders the smectite-rich gouges prone to accommodate large seismic slips. During megathrust earthquakes, such lubricating effect may result in the easy propagation of seismic ruptures in smectite- and water-rich sediments at shallow depths. Similarly, the presence of water can promote large displacements during landslide collapse.

Made available in DSpace on 2014-06-11T19:26:15Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-02-04Bitstream added on 2014-06-13T18:29:47Z : No. of bitstreams: 1 benessiuti_mf_me_bauru.pdf: 4336666 bytes, checksum: b38250d3f308f9ca935e1e148d3fa7a0 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / A região das nascentes do ribeirão Guaratinguetá, localizada no contraforte da Serra da Mantiqueira, Vale do Paraíba, tem sido intensamente modificada por ações antrópicas criando condições que favorecem os movimentos de massa, princiapalmente devido à supressão da mata nativa. Estas ações, somada ao aumento a intensidade de chuvas sobre uma complexa geologia da região, têm potencializado os escorregamentos translacionais, de modo que foram registradas mais de 40 ocorrências, nas chuvas do final de 2008 e início de 2009. Neste contexto, as proposta desta dissertação é de identificar os mecanismos que geram essas instabilidades através da avaliação das características geotécnicas de dois escorregamentos característicos na bacia do ribeirão Guaratinguetá. Para isso, as atividades envolveram ensaios de laboratório e de campo. No laboratório foram realizados ensaios para a caracterização completa das amostras, ensaios de sucção, para determinação das curvas características, e ensaios de cisalhamento direto, para determinação dos parâmetros de resistência. No campo, foram determinadas as propriedades hidráulicas através do permeâmetro de Guelph e a resistência à penetração dos horizontes utilizando o Penetrômetro Dinâmico de Cone. O estudo dos possíveis processos de identificação de instabilidade foi realizado a partir de retro-análises dos dois escorregamentos estudados, através do software SLOPE/W, da GeoSlope, e de simulações de cenários, através do modelo matemático Shalstab. Nestas análises, foram consideradas diferentes hipóteses relativas à presença de água no subsolo, onde foram verificados os respectivos fatores de segurança. Os resultados das retro-análises indicam coerência entre as superfícies previstas e observadas no campo, para a condição de solo saturado acima da superfície de ruptura e solo na umidade residual... / The land degradation process as consequences of deforestation and farming activities at the northem part of the Guaratinguetá creek watershed, Paraíba Valley, is compromising the environmental balance of the region traduced by increase in the numbers of shallow landslides occurring during rain seasons. In summer 2009, more than 40 shallow landslides occurred during an intense rainfall with serious consequence for the local population. In this context, the purpose of this dissertation is to understand the mechanism that triggered the soil movement based on geotechnical investigation of two landslides in the Guaratinguetá creek watershed. The geotechnical profiles of two landslides and the hydraulic parameters were determined by field tests using Dynamic Cone Penetrometer and Guelph Permeameter. In laboratory, physical and mechanical soil properties were determined. The shear strength parameters were obtained by direct shear tests on undisturbed speciments for three initial gravimetric water contents (residual, natural and saturated). The instability process was inferrred by back-analysing these two landslides using the SLOPE/W, GeoSlope, and simulating scenarios using SHALSTAB model. These analyses took into account the physical properties and the shear strength parameters of the solis for different water contents. The predicted slip surfaces were in agreement with the observed ones when the analyses considered the soil parameters above the slip surface as saturated and the soil parameters below the slip surface as in residual water content condition. The susceptibility map using SHALSTAB were then carried out for the soil parameters for satured condition. The influence of the vegetation (root strength) was inserted in the analyses by a scale factor based onn Algebra Map Technique. The validation of the applied methodology was verified by crossing the predicted unstable... (Complete abstract click electronic access below)

Made available in DSpace on 2014-06-11T19:32:17Z (GMT). No. of bitstreams: 0 Previous issue date: 2004-04-14Bitstream added on 2014-06-13T19:02:49Z : No. of bitstreams: 1 araujo_pc_dr_rcla.pdf: 6448977 bytes, checksum: a417ef7a09cc4dcb465b4c84dfc411b9 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Os escorregamentos são os principais processos ligados à dinâmica externa, que estão em desenvolvimento nas escarpas da Serra do Mar, o que tem despertado grande interesse científico e motivado o desenvolvimento de trabalhos visando o entendimento de seus mecanismos, pois estão intimamente relacionados a situações de risco. Contemplando as mais variadas formas de abordagens, os trabalhos desenvolvidos nessa região tem um ponto em comum: As análises, em sua grande maioria, são feitas através de modelos analógicos, que utilizam medidas diretas e apresentam resultados qualitativos. No presente trabalho, apresenta-se uma abordagem quantitativa que utiliza recursos da geotecnologia para gerar mapas de suscetibilidade a escorregamentos através do método pesos das evidências (WOFE), baseado em probabilidade condicional ou Bayesiana. Esse método é utilizado para medir as relações espaciais entre eventos já ocorridos e os mapas de evidências associados aos condicionantes desses eventos. Um pressuposto importante desse método é a independência condicional entre as evidências, sendo sua avaliação feita através dos métodos estatísticos qui-quadrado e teste global. O método proposto foi aplicado em uma área do Município de São Sebastião, litoral norte do Estado de São Paulo, utilizando mapas com padrões binários. A obtenção dos mapas binários obedeceu ao critério de contraste máximo, que é a medida de correlação espacial entre os escorregamentos e as evidências. A avaliação dos resultados obtidos indica que a abordagem utilizada apresenta potencial para aplicação em estudos sobre suscetibilidade a escorregamentos e avaliações sobre risco, em função do uso de probabilidade condicional. / Landslide is the main process linked to external dynamic that take place in the Mar Mountain Range (Serra do Mar) escarpments. It has been of great scientific interest and has motivated researches that aim the comprehension of its mechanisms. The approaches have been diversified, but with a common sense: the analyses are mainly made through analogical models, using direct measurements and showing qualitative results. Alternatively, this work shows a quantitative approach, using geotechnology resorts that give raise to landslides susceptibility maps through the weights of evidence method (WOFE). This method, based in the conditional or bayesian probability, is useful to measure the spatial correlations among events and evidence maps, which are selected as factors that influence the occurrence of these events. The conditional independence between the evidence maps is an important purpose of the WOFE method, and the evaluation is made through the overall test and chi-square statistic methods. The method was applied in an area of the São Sebastião County, in the North Coast of the São Paulo State, Brazil, using binary maps. The binary maps were the result of the reclassification using the maximum contrast criterion, which is the measurement of the spatial correlation between landslides and evidences. The evaluation of the results show that the approach presents potential for application in studies on landslide susceptibility and evaluations on risk, based of the use of conditional probability.

Orientador: Paulina Setti Riedel / Banca: Ardemirio de Barros Silva / Banca: Arlei Benedito Macedo / Banca: Ricardo Vedovello / Banca: Iandara Alves Mendes / Resumo: Os escorregamentos são os principais processos ligados à dinâmica externa, que estão em desenvolvimento nas escarpas da Serra do Mar, o que tem despertado grande interesse científico e motivado o desenvolvimento de trabalhos visando o entendimento de seus mecanismos, pois estão intimamente relacionados a situações de risco. Contemplando as mais variadas formas de abordagens, os trabalhos desenvolvidos nessa região tem um ponto em comum: As análises, em sua grande maioria, são feitas através de modelos analógicos, que utilizam medidas diretas e apresentam resultados qualitativos. No presente trabalho, apresenta-se uma abordagem quantitativa que utiliza recursos da geotecnologia para gerar mapas de suscetibilidade a escorregamentos através do método "pesos das evidências" (WOFE), baseado em probabilidade condicional ou Bayesiana. Esse método é utilizado para medir as relações espaciais entre eventos já ocorridos e os mapas de evidências associados aos condicionantes desses eventos. Um pressuposto importante desse método é a independência condicional entre as evidências, sendo sua avaliação feita através dos métodos estatísticos qui-quadrado e teste global. O método proposto foi aplicado em uma área do Município de São Sebastião, litoral norte do Estado de São Paulo, utilizando mapas com padrões binários. A obtenção dos mapas binários obedeceu ao critério de contraste máximo, que é a medida de correlação espacial entre os escorregamentos e as evidências. A avaliação dos resultados obtidos indica que a abordagem utilizada apresenta potencial para aplicação em estudos sobre suscetibilidade a escorregamentos e avaliações sobre risco, em função do uso de probabilidade condicional. / Abstract: Landslide is the main process linked to external dynamic that take place in the Mar Mountain Range (Serra do Mar) escarpments. It has been of great scientific interest and has motivated researches that aim the comprehension of its mechanisms. The approaches have been diversified, but with a common sense: the analyses are mainly made through analogical models, using direct measurements and showing qualitative results. Alternatively, this work shows a quantitative approach, using geotechnology resorts that give raise to landslides susceptibility maps through the "weights of evidence" method (WOFE). This method, based in the conditional or bayesian probability, is useful to measure the spatial correlations among events and evidence maps, which are selected as factors that influence the occurrence of these events. The conditional independence between the evidence maps is an important purpose of the WOFE method, and the evaluation is made through the overall test and chi-square statistic methods. The method was applied in an area of the São Sebastião County, in the North Coast of the São Paulo State, Brazil, using binary maps. The binary maps were the result of the reclassification using the maximum contrast criterion, which is the measurement of the spatial correlation between landslides and evidences. The evaluation of the results show that the approach presents potential for application in studies on landslide susceptibility and evaluations on risk, based of the use of conditional probability. / Doutor

Landslides are relatively frequent in Ottawa due to the presence of sensitive marine clays (Leda clay or Champlain Sea clay), and the presence of natural or climatic triggers such as rainfall or snowmelt. A geographic information system (GIS) based modeling tool has been developed to assess and predict climate (rainfall and snowmelt)-induced landslides in the sensitive marine clays of the Ottawa region. The Transient Rainfall Infiltration and Grid-based Regional Slope-Stability (TRIGRS) model is used in a GIS framework to investigate the influence of rainfall and snowmelt on shallow landslides through the Ottawa region, with respect to time and location. First, the GIS and TRIGRS models are combined to assess landslide susceptibility with respect to rainfall. The GIS-TRIGRS approach requires topographic, geologic, hydrologic, and geotechnical information of the study area. In addition to this technical information (input data), rainfall intensity data for different durations (5 minutes, and 6, 12, 18, and 24 hours), and historical data of the regional landslides is required. This data is used to verify the locations of predicted landslide-susceptible areas with respect to historical landslide maps in the area. The generated results from the GIS-TRIGRS model were verified by comparing the predicted and historical locations of shallow landslides induced by rainfall throughout the Ottawa region. The comparison results showed a high correlation between the predicted areas of landslides and the previously reported landslides. In addition, the results also indicated that not all previous landslides in Leda clays were triggered by rainfall. The second application of the developed GIS-TRIGRS approach was used to assess and predict snowmelt-induced landslides in areas of sensitive marine clay in the Ottawa region. Similar to the first analysis, the approach requires the following input data: topographic, geologic, hydrologic, geotechnical, snowmelt intensity data for various periods (6–48 hours, 3–15 days, 25 days, and 30 days), This approach also requires data indicating the location of historical landslides in the study area. Using this data, we examine both the timing and location of shallow landslides due to snowmelt in a GIS-based framework. The developed model was validated by comparing the predicted landslide-susceptible areas to historical landslide maps in the study area. A high correlation between predicted and historical landslide location trends was obtained, confirming that the developed GIS-TRIGRS model can predict the snowmelt-induced landslide susceptibility in the sensitive marine clays relatively well. The model results reinforced the conclusion that areas with high slopes and sensitive marine clays were more prone to snowmelt-induced landslides. Finally, in a Geographic Information System (GIS) the landslide occurrence susceptibility in the Ottawa area was modeled. Results of such models are presented as maps showing landslide susceptibility in Champlain Sea clays (Leda clays) in the Ottawa area due to both rainfall and snowmelt. Various input data was collected and entered into a GIS and TRIGRS model. The main categories of such inputs are climate, topography, geology, hydrology, and geotechnical data. The rainfall and snowmelt intensity data was extracted for 24 to 48 hour periods from Environment and Climate Change Canada historical climate records. Thereafter, the factor of safety was calculated in order to determine the stability of slopes across the study area. The model assesses the effects of rainfall and snowmelt on landslide occurrence, and based on the calculated factor of safety at each pixel of the study area, the model calculates the landslide susceptibility. The results presented in this thesis will provide a geotechnical basis for making appropriate engineering decisions during slope management and land use planning in the Ottawa region.