Portland State University. Department of Geography
Larry W. Price
Date of Award
Master of Science (M.S.) in Geography
1 online resource (181 p.)
Mass-wasting, Regional planning
Land-use planning takes into consideration geologic hazards in order to protect both life and property. One type of geologic hazard is mass movement. Mass movement is a collective term for the downslope movement of mass units of debris e.g., bedrock, soil, and subsurface material, resulting from the influence of gravity and involving transporting media such as ice, snow, water, and air. As population increases, further pressures are placed on existing land use. Many areas once considered unsuitable for development due to steep slope or other physical characteristics are now experiencing problems. These areas, due to their physical characteristics, can be susceptible to mass movement. The problem is, information related to the areal distribution of susceptibility is most often not available for input to the land-use planning process. This thesis is proposing a methodology to provide general-level mass movement susceptibility maps.
The methodology is a computer application utilizing the Harvard I. M. G. R. l. D. (IMGRID) System. IMGRID is a system using grid cells as the basic units of data storage, analysis, retrieval, and display. Basically, the methodology consists of three major components or phases: (1) providing the computer with data acceptable to the machine and computer programs (input); (2) manipulation of the data and storage of map results within the machine's memory (processing); and (3) the retrieval and display of results (output).
The processing of the data is organized around susceptibility models which generate computer maps identifying areas susceptible to mass movements. Areas susceptible to moss movements are defined as portions of the landscape characterized by a set of natural characteristics existing in a stable state which will yield a failure of the material if acted upon by an external or internal triggering event either natural or man-induced.
The methodology was applied to a small area in Southwest Washington as a demonstration of how one mechanically follows it from beginning to end. Nine mass movement models were constructed based on the Varnes’ classification system and applied to a data bank containing eleven data variables. The susceptibility mops generated were analyzed to determine the significant mapping classes using the statistical output from IMGRID.
Cimmery, Vern Walter, "A methodology for determining mass movement susceptibility for land-use planning" (1976). Dissertations and Theses. Paper 2360.