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The Paonia-McClure Pass area of Colorado has been recognized as a region highly susceptible to mass movement. Because of the dynamic nature of this landscape, accurate methods are needed to predict susceptibility to movement of these slopes. The area was evaluated by coupling a geographic information system (GIS) with logistic regression methods to assess susceptibility to landslides. We mapped 735 shallow landslides in the area. Seventeen factors, as predictor variables of landslides, were mapped from aerial photographs, available public data archives, ETM + satellite data, published literature, and frequent field surveys. A logistic regression model was run using landslides as the dependent factor and landslide-causing factors as independent factors (covariates). Landslide data were sampled from the landslide masses, landslide scarps, center of mass of the landslides, and center of scarp of the landslides, and an equal amount of data were collected from areas void of discernible mass movement. Models of susceptibility to landslides for each sampling technique were developed first. Second, landslides were classified as debris flows, debris slides, rock slides, and soil slides and then models of susceptibility to landslides were created for each type of landslide. The prediction accuracies of each model were compared using the Receiver Operating Characteristic (ROC) curve technique. The model, using samples from landslide scarps, has the highest prediction accuracy (85 %), and the model, using samples from landslide mass centers, has the lowest prediction accuracy (83 %) among the models developed from the four techniques of data sampling. Likewise, the model developed for debris slides has the highest prediction accuracy (92 %), and the model developed for soil slides has the lowest prediction accuracy (83 %) among the four types of landslides. Furthermore, prediction from a model developed by combining the four models of the four types of landslides (86 %) is better than the prediction from a model developed by using all landslides together (85 %).

Mass movement can be activated by earthquakes, rapid snowmelt, or intense rainstorms in conjunction with gravity. Whereas mass movement plays a major role in the evolution of a hillslope by modifying slope morphology and transporting material from the slope to the valley, it is also a potential natural hazard. Determining the relationships of frequency and magnitude of landslides are fundamental to understanding the role of landslides in the study of landscape evolution, hazard assessment, and determination of the rate of hillslope denudation. We mapped 735 shallow and active landslides in the Paonia to McClure Pass area of western Colorado from aerial photographs and field surveys. The study area covers ∼815 km 2 . The frequency–magnitude relationships of the landslides illustrate the flux of debris by mass movement in the area. The comparison of the probability density of the landslides with the double Pareto curve, defined by power scaling for negative slope ( α ), power scaling for positive slope ( β ), and location of rollover ( t ), shows that α  = 1.1, β  = 1.9, and t  = 1,600 m 2 for areas of landslides and α  = 1.15, β  = 1.8, and t  = 1,900 m 3 for volumes of landslides. The total area of landslides is 4.8 × 10 6  m 2 and the total volume of the landslides is 1.4 × 10 7  m 3 . The areas ( A ) and the volumes ( V ) of landslides are related by V  = 0.0254 ×  A 1.45 . The frequency–magnitude analysis shows that landslides with areas ranging in size from 1,600 to 20,000 m 2 are the most hazardous landslides in the study area. These landslides are the most frequent and also do a significant amount of geomorphic work. We also developed a conceptual model of hillslope development to upland plateau driven by river incision, shallow landsliding, and deep-seated large landsliding. The gentle slope to flat upland plateau that dominated the Quaternary landscape of the study area was modified to the present steep and rugged topography by the combined action of fluvial incision and glacial processes in response to rock uplift, very-frequent shallow landsliding, and less-frequent deep-seated landsliding.

Soil temperature directly responds to atmospheric temperature, although a variety of climatic and soil variables influence actual soil temperature. Whereas most relationships about soil temperature have been established at a point, this research assesses the relationships of soil temperature at three depths to a variety of climatic variables along a 200-km transect in central Oklahoma. Our observations support known conclusions that soil temperatures increased at all depths from east to west. Sub-surface temperature changes lagged one week behind atmospheric conditions. A precipitation event of 2.0 cm is required to have a significant impact on soil temperature at all depths. The location of the field site along the transect and the week of data collection explained significant amounts of soil temperature variability at each of the three depths evaluated. Elevation, soil texture, and antecedent environmental conditions prior to data collection were combined with spatial (site location) and temporal (sample week) variables to explain additional levels of soil temperature variability.

This paper assesses the impact of the destructive 1953 Flint tornado upon the people currently living in the community that was destroyed. Personal interviews conducted with people now residing along the path of the 1953 tornado revealed that one's age and length of residence in the immediate area influenced one's awareness of the Flint disaster. A person's level of awareness of the 1953 Flint tornado was found to have a significant impact on the nature of the individual's long- and short-range response to the tornado threat. Those who were well aware of the violent 1953 tornado were more likely than those who were unaware of that storm to take appropriate precautions when a tornado warning was issued. Moreover, the level of awareness of this past event was found to be more important than having experienced a tornado in determining whether or not a person now responds appropriately to a tornado warning.

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