We reconstruct 2D simulation to 3D scene and integrated a fluid-solid coupling based on FLO-2D model. Furthermore we add the friction and bump. From the point of view of fluid-solid coupling, we using the flow resistance and yield stress our proposed method make the fluid behaviour and runout more realistic comparing to other fluid-solid coupling research. Besides, from the point of view of debris flow simulation, we integrate the fluid-solid coupling into the debris flow simulation. And we can handle the bump of debris flow regarding trees, stone or house compared with other debris flow simulation.

The debris-flow initiation variable of clay mineralogy is examined for Holocene age debris-flow deposits across the Colorado Plateau. A Kolmogorov-Smirnov two-sample test between 25 debris-flow producing shale units and 23 shale units rated as not producing debris-flows found a highly significant difference between shale unit kaolinite-illite and montmorillonite clay content. Debris-flow producers tend to have abundant kaolinite and illite (61.5% of clays) and small amounts of montmorillonite (10.4%). Clay sample soluble cation (Na, Ca, K, and Mg) content could not be used to accurately divide the data set into debris-flow producers and debris-flow non-producers by either cluster analysis or a Kolmogorov-Smirnov two-sample test.AVIRIS hyperspectral data reveal that debris-flow deposits, colluvium, and some shale units in Cataract Canyon, Utah display the double-absorption feature characteristic of kaolinite at 2.2 µm. Lab-based reflection spectra and semi-quantitative x-ray diffraction results show that Cataract Canyon debris-flow matrix clays are dominated by kaolinite and illite and lacking in montmorillonite. A surface material map showing the spectral stratigraphy of the study area was created from AVIRIS data classified using an artificial neural network and compares favorably to existing geologic data for Cataract Canyon. A debris-flow initiation potential map created from a GIS-based analysis of surface materials, slope steepness, slope aspect, and fault maps shows the greatest debris-flow initiation potential in the study area to coincide with outcrops of the Moenkopi Formation on steep (>20%), southwest-facing slopes. Small areas of extreme debris-flow initiation potential are located where kaolinite and illite clay-rich colluvial wedges are located on southwest-facing walls of Colorado River tributary canyons. The surface materials map shows formations clearly when they remain relatively consistent in composition and exposure throughout the study area, such as the White Rim Sandstone and most clay-rich members of the Moenkopi Formation. The debris-flow producing Organ Rock Shale and Halgaito Formation were shown inconsistently on the surface materials map, likely as a result of compositional variations in the study area. The results of this study provides evidence that hyperspectral imagery classified using an ANN can be successfully used to map the spectral stratigraphy of a sparsely vegetated area such as Cataract Canyon.

More than 1100 debris flows were mobilized from shallow landslides during a rainstorm from 9 to 13 September 2013 in the Colorado Front Range, with the vast majority initiating on sparsely vegetated, south facing terrain. To investigate the physical processes responsible for the observed aspect control, we made measurements of soil properties on a densely forested north facing hillslope and a grassland-dominated south facing hillslope in the Colorado Front Range and performed numerical modeling of transient changes in soil pore water pressure throughout the rainstorm. Using the numerical model, we quantitatively assessed interactions among vegetation, rainfall interception, subsurface hydrology, and slope stability. Results suggest that apparent cohesion supplied by roots was responsible for the observed connection between debris flow initiation and slope aspect. Results suggest that future climate-driven modifications to forest structure could substantially influence landslide hazards throughout the Front Range and similar water-limited environments where vegetation communities may be more susceptible to small variations in climate.

Two distinct studies within the Saltville Valley of southwestern Virginia revealed insights into local Pleistocene geology and paleontology. A variety of analytical techniques were applied to gravel deposits within the paleontological site of SV-5/7 that revealed this unit is very poorly sorted, has a subangular matrix, and contains significant components of silt and sand in addition to rounded cobbles. These results suggest that rather than being deposited by fluvial processes as previously suggested, these gravels were likely the result of one or many debris flows. Additionally, the identity of fossil muskoxen from Saltville was reassessed using cranial and dental material. The results of the comparative anatomy of Bootherium and Ovibos specimens suggest that it may be possible to distinguish between fossil muskoxen genera using teeth, and to a lesser extent, cranial measurements. This analysis reaffirms that Bootherium is the only muskoxen definitively known from the Pleistocene of the Saltville Valley.

No description available.

No description available.

This study investigates the February 17th, 2006 massive rockslide that occurred in the island of Leyte, Philippines following heavy rainfall and four minor earthquakes. The rockslide is considered one of the largest and most catastrophic slides in the last few decades as it completely inundated the village of Guinsaugon, taking the lives of approximately 1,400 of the 1,800 residents of the village. The distinct element simulation of the rockslide is performed using 3DEC (Three-Dimensional Distinct Element Code) in order to investigate the underlying triggering mechanism of the slide as well as the behavior of the debris flow. The 3DEC models were established based on field observations from the U.S. Reconnaissance team and material and joint properties based on in-situ and laboratory test results. The possible triggering mechanisms considered in the distinct element analyses were the rainfall-induced hydraulic pressurization of the fault forming part of the main scarp, as well as the seismic acceleration due to the minor earthquakes that occurred the morning of the slide. The results of the analyses and simulations indicate that the rainfall-induced hydraulic pressurization of the fault was potentially the main trigger for the initiation of the slide. The minor earthquakes, which occurred before and around the time of the slide initiation, appeared to have very little effect on the triggering mechanism and the debris flow are comparable to witness accounts and field observations. The results presented in this study are expected to provide better understanding of rockslides such as the one that occurred in the Philippines on February 17, 2006. With further improvements in computational capabilities in the future, distinct element simulations can have the potential to reliably predict the initiation and behavior of slides, and help mitigate their impact. / Master of Science

Le massif du Cantal, localisé dans la province volcanique Cénozoïque du Massif Central (France), est le plus grand complexe volcanique Miocène d’Europe. Il est majoritairement constitué de brèches volcanoclastiques qui lui confèrent des dimensions impressionnantes et une morphologie surbaissée. Des observations de terrain, couplées à des datations K-Ar, nous ont permis de reconstituer l’évolution morpho-structurale, la dynamique éruptive et l’histoire volcanique du massif. Après avoir contraint dans l’espace et dans le temps une séquence stratigraphique identique tout autour du massif, nous montrons qu’il existe des évidences chrono-stratigraphiques, structurales et géomorphologiques en faveur de la formation d’une caldeira centrale de 8 x 10 km il y a environ 8 Ma occupée par un lac. L’étude morphologique et sédimentologique de la principale unité bréchique du massif, le Grand Écoulement Bréchique, nous a conduit à le définir comme l’un des plus importants debris flow syn-éruptifs connus au monde dont nous estimons un volume de l’ordre de 100 km3. Nous proposons que cet écoulement résulte d’une éruption sous-lacustre intracaldeira majeure. L’interaction entre un magma juvénile et l’eau du lac de caldeira, selon un dynamisme surtseyen, a initié la formation du debris flow qui s’est propagé sur les pentes externes du volcan à 360° jusqu’à plus de 25 km de sa source. Cette étude ouvre des perspectives d’une part quant aux risques volcaniques liés aux éruptions sous-lacustres intracaldériques majeures, et d’autre part quant à la possibilité de reconstituer la morphologie passée de la source d’un écoulement bréchique volcanoclastique âgé de plusieurs Ma, par l’étude de son dépôt selon des critères sédimentologiques et morphologiques.Dans un deuxième temps, la combinaison de nouvelles datations K-Ar et d’observations de terrain nous ont permis de reconstituer l’histoire volcanique du plateau du Cézallier, siège de la plus jeune activité volcanique de France métropolitaine, du plateau de l’Aubrac, et également la chronologie du volcanisme le long du Sillon Houiller. Nous avons pu ainsi établir les relations spatio-temporelles entre le massif du Cantal et les provinces volcaniques adjacentes révélant le rôle important des fractures héritées de l’Hercynien pour la remontée des magmas. Nous confirmons ainsi une migration spatio-temporelle vers le nord du volcanisme en Auvergne. Finalement, l’acquisition au cours de ce travail de 47 nouveaux âges K-Ar de 12,8 Ma à 9 ka complète la chronologie du volcanisme du Massif Central en précisant sa distribution spatio-temporelle. / The Cantal massif, located in the French Cenozoic volcanic province, is the largest Miocene volcano in Europe. It is mainly composed of volcaniclastic breccias giving impressive dimensions and a shield-like morphology. Field observations, coupled with K-Ar datings, allowed us to reconstruct the morpho-structural evolution, the eruptive dynamics and the volcanic history of the massif. We first constrained a stratigraphic sequence which is identical all around the massif. Then, we show that it exists from chrono-stratigraphic, structural and geomorphologic evidences a 8 x 10 km central caldera ca. 8 Myrs ago occupied by a lake. The sedimentological and morphological study of the main breccia unit, the Large Breccia Flow, led us to define it as one of the largest syn-eruptive debris flow in the world. We estimate its volume at ca. 100 km3. We propose that this debris flow resulted from a major intracaldera lake eruption. The interaction between a juvenile magma and the water of the caldera lake, with a surteyan dynamics, initiated the debris flow that propagated on the external slopes of the volcano at 360° until 25 km from its source. This study opens outlets on one hand to volcanic hazards related to major intracaldera lake eruptions ; on the other hand, we show that it is possible to reconstruct the former source morphology of a several Myrs-old volcaniclastic breccia flow by studying the sedimentological and morphological criterion of its deposit.Furthermore, the combination of new K-Ar datings with field observations allowed us to reconstruct the volcanic history of the Cézallier plateau (site of the youngest volcanic activity in the continental France), of the Aubrac plateau, and also the volcanism along the Sillon Houiller. Consequently, we established the spatio-temporal relationships between the Cantal massif and the adjacent volcanic provinces, highlighting the important role of the Hercynian inherited fractures in the magmas ascent. We thus confirm the spatio-temporal migration toward the north in Auvergne. Finally, the acquisition of 47 new K-Ar ages ranging from 12.8 Ma to 9 ka conveys new time constraints on the chronology of Massif Central volcanism by precising its spatio-temporal distribution.

Por se tratar de um fenômeno complexo, a modelagem computacional tem sido utilizada na tentativa de simular o comportamento de fluxos de detritos. Um dos modelos computacionais é o Kanako-2D. O presente trabalho realizou análise de sensibilidade desse modelo em relação a alcance, área de erosão, área de deposição, área total atingida e largura do fluxo. Os valores dos parâmetros de entrada do Kanako-2D, cujas faixas de variação foram estabelecidas a partir de revisão bibliográfica, foram alterados individualmente enquanto os demais eram mantidos nos valores padrão do modelo. Os parâmetros analisados foram: diâmetro dos sedimentos, coeficiente de rugosidade de Manning, coeficiente de taxa de deposição, coeficiente de taxa de erosão, massa específica da fase fluida, massa específica do leito, concentração de sedimentos e ângulo de atrito interno. Foi utilizada uma vertente real com histórico de ocorrência de fluxos de detritos (bacia hidrográfica do arroio Böni, em Alto Feliz e São Vendelino/RS) e uma vertente hipotética com as mesmas características da vertente real para avaliar o efeito da topografia na propagação do fluxo. Também foram simuladas diferentes condições de terreno na propagação do fluxo de detritos. A sensibilidade do modelo foi quantificada a partir de três métodos: (a) análise por rastreamento, que indicou massa específica do leito, ângulo de atrito interno e concentração de sedimentos como os parâmetros que causam maior sensibilidade do modelo; (b) análise regional, indicando que os parâmetros massa específica do leito, ângulo de atrito interno e massa específica da fase fluida apresentaram maior sensibilidade do modelo; e (c) análise das variâncias, em que os parâmetros que mais causaram sensibilidade ao modelo foram coeficiente de taxa de erosão, diâmetro dos sedimentos e massa específica do leito. Os resultados apontaram que, de maneira geral, os parâmetros que geram maior sensibilidade no modelo são massa específica do leito, ângulo de atrito interno e concentração de sedimentos. As maiores variações relativas, no entanto, foram observadas nos parâmetros massa específica do leito, ângulo de atrito interno e massa específica da fase fluida. As maiores sensibilidades foram verificadas, em ordem decrescente, para área de erosão, área total, área de erosão, área de deposição, alcance e largura na vertente real e, para área total, alcance e largura na vertente hipotética. A condição de terreno que gerou maior alcance e área atingida foi de 45° de inclinação na encosta e 17° de inclinação na planície aluvial. / Due to a complex phenomenon, computational modeling has been used in an attempt to simulate the behavior of debris flows. One of the computational models is Kanako-2D. The present work carried out sensitivity analysis of this model in relation to length, erosion area, deposition area, total reached area and flow width. The values of the Kanako-2D input parameters, which ranges were established from literature review, were individually changed while the others were kept at the standard values of the model. The analyzed parameters were: sediment diameter, Manning roughness coefficient, coefficient of deposition rate, coefficient of erosion rate, mass density of the fluid phase, mass density of bed material, sediment concentration and internal friction angle. It was used a real slope-site with a history of occurrences of debris flow (Böni river basin in Alto Feliz and São Vendelino/RS) and a hypothetical slope-site with the same characteristics of the real one to evaluate the effect of the topography in the propagation of the flow. Different hillslope and alluvial fan conditions were also simulated in order to evaluate the length and reached area in the propagation of the flow. The sensitivity was quantified from three methods: (a) screening analysis, which indicated mass density of bed material, internal friction angle and sediment concentration as the parameters that cause bigger sensitivity in the model; (b) regionalized analysis, indicate that the parameters mass density of bed material, internal friction angle and mass density of the fluid phase showed higher sensitivity in the model; and (c) variances analysis, indicated that coefficient of erosion rate, sediment diameter and mass density of bed material showed higher sensitivity in the model. The results showed that, in general, the parameters that generate the higher sensitivity in the model are mass density of bed material, internal friction angle and concentration. The largest relative variation, however, in the response of the model were observed in mass density of bed material, internal friction angle and mass density of fluid phase. In descending order, the highest sensitivities were verified for erosion area, total area, deposition area, length and width for the real slope-site and total area, length and width for the hypothetical slope-site. The terrain condition that generated the largest length and reached area was 45° on the hillslope and 17º on the alluvial fan.

O objetivo dessa pesquisa é avaliar a vulnerabilidade das construções às corridas de detritos, na bacia do rio Guaxinduba município de Caraguatatuba SP. Para tanto, aplicou-se o método PTVA (Papathoma Tsunami Vulnerability Assessment) que vem sendo aplicado em diferentes países considerando os diferentes processos perigosos naturais. Nesta pesquisa, a vulnerabilidade foi avaliada conforme as ações mitigadoras do poder público. As etapas metodológicas aplicadas foram: a) Classificação dos depósitos de corridas de detritos na área de estudo; b) Seleção dos critérios que afetam a vulnerabilidade das construções e sistematização de banco de dados; c) Cálculo da vulnerabilidade e d) Mapeamento da vulnerabilidade final. Dentre os instrumentos metodológicos utilizados, ressalta-se a utilização do ArcGis versão 10.0 e fotografia aérea. Ao todo, foram mapeadas 38 áreas que culminaram na distribuição da vulnerabilidade final com 7,9 % alta e 68,4 % média e 23,7% baixa. Nesse sentido, verificou-se a relevante variação de aproximadamente 30% entre a vulnerabilidade mais baixa (55%) e a mais alta (83%). Além disso, concluiu-se que a norte da Estrada do Cantagalo, bem como nas Alamedas dos Castanheiros e Pessegueiros, área central da bacia mapeada, concentra-se o maior número de áreas com vulnerabilidade elevada. Diante da escassez dos procedimentos metodológicos no Brasil que visem avaliar a suscetibilidade, a vulnerabilidade ou o risco, referentes às corridas de detritos; esta pesquisa destaca, ainda, a importância destes trabalhos no cenário de riscos ambientais, contribuindo com os esforços mundiais de redução de risco. / The objective of this research is to assess the vulnerability of buildings to debris flow in the river basin Guaxinduba - Caraguatatuba county - SP. To this end, we applied the PTVA (Papathoma Tsunami Vulnerability Assessment) method that has been applied in different countries considering different natural hazardous processes. In this research, the vulnerability was judged according to the mitigation actions of government. The methodological steps were applied: a) Classification of debris flow deposits in the study area; b) Selection criteria that affect the vulnerability of buildings and systematized database; c) Calculation of vulnerability and d) Mapping the final vulnerability. Among the methodological tools used, we emphasize the use of ArcGIS version 10.0 and aerial photography. In general 38 areas which resulted in the following distribution of the final vulnerability were surveyed: 7.9% high, 68.4% average and 23.7% presented low vulnerability. Accordingly, there was a significant variation of approximately 30% between the lowest vulnerability (55%) and the highest (83%). Furthermore, it was concluded that the northern of Cantagalo Road, as well as the alleys of Castanheiros and Pessegueiros, central area of the basin mapped, concentrates the largest number of areas with high vulnerability. Given the scarcity of methodological procedures in Brazil to evaluate the susceptibility, vulnerability or risk related to debris flow; This research also highlights the importance of these works on environmental risk scenario, contributing to global efforts to reduce risk.