SINMAP 2.0 (Stability Index MAPping) is an ArcGIS 9.0 plug-in that implements the computation and mapping of a slope stability index based upon geographic information, primarily digital elevation data. This report describes the theoretical basis for the calculation of the stability index, describes the implementation, presents several case studies and describes use of the accompanying software. SINMAP has its theoretical basis in the infinite plane slope stability model with wetness (pore pressures) obtained from a topographically based steady state model of hydrology. Digital elevation model (DEM) methods are used to obtain the necessary input information (slope and specific catchment area). Parameters are allowed to be uncertain following uniform distributions between specified limits. These may be adjusted (and calibrated) for geographic ccalibration regionsd based upon soil, vegetation or geologic data. The methodology includes an interactive visual calibration that adjusts parameters while referring to observed landslides. The calibration involves adjustment of parameters so that the stability map ccapturesd a high proportion of observed landslides in regions with low stability index, while minimizing the extent of low stability regions and consequent alienation of terrain to regions where landslides have not been observed. This calibration is done while simultaneously referring to the stability index map, a specific catchment area and slope plot (of landslide and non landslide points) where lines distinguish the zones categorized into the different stability classes and a table giving summary statistics. The current implementation of SINMAP 2.0 is a plug-in to the ArcGIS ArcMap geographic information system (GIS) from Environmental Systems Research Institute, Inc. (ESRI). This utilizes ArcMap for its standard GIS functionality such as the input and organization of data and the presentation and output of results. SINMAP is grid based, requiring ArcGIS version 9.0 or higher.
Pack, R.T., Tarboton, D.G. and Goodwin, C.N. 1999. SINMAP - A Stability Index Approach to Terrain Stability Hazard Mapping, User's Manual. Produced in ArcView Avenue and C++ for Forest Renewal B.C. under Research Contract No: PA97537-0RE. (has averaged 3 downloads/day for 7 years)