Laserfiche WebLink
<br /> <br />EXPLANATION <br />IBI Landslide learthflowl deposit <br /> <br />I ~ I Active landslide <br /> <br /> <br />Area susceptible to slidin9 <br /> <br />..1 <br /> <br />:.1 <br /> <br />o <br />I <br /> <br />2000 <br />I <br /> <br />N <br /> <br />4000 <br />I <br /> <br />FEET <br /> <br />Figure 1 S. Detail from the Morrison quadrangle folio showing areas susceptible to landsliding (Scott. <br />1972). <br /> <br />ventory is a vital element of the preparation process. <br />Overlaying a geologic map with an inventory map which <br />shows existing landslides can identify specific Iandslide- <br />. prone geologic units. This information can then be ex- <br />trapolated to predict new areas of potentiallandsliding. <br />More complex maps include additional information such <br />as slope angle, slope aspect, and drainage. <br /> <br />Landslide hazard maps <br />Hazard maps show the areal extent of threatening pro- <br />cesses: where landslide processes have occurred in the <br />past, where they occur now, and the probability in <br />various areas that a landslide will occur in the future <br />(Figure 16). For a given area, they contain detailed infor- <br />mation on the types of landslides, extent of slope sub- <br />ject to failure, probable maximum extent of ground <br /> <br />26 <br /> <br />. <br /> <br />movement, and the probable frequency of failure. These <br />maps can be used to predict the relative degree of <br />hazard in a landslide area. <br /> <br />Mapping in Colorado <br />Selection of map scale and format <br />Map scale and format should be determined by the level <br />of detail necessary to depict the particular problem <br />area, the land use being considered, and data being <br />presented. However, other factors such as the avai1abili- <br />ty of funds, staff, or time may actually have more in- <br />fluence over the final product. The U.S. Geological <br />Survey (1982, p. 21) notes that all landslide hazard maps <br />"are a compromise between detail and reliability and the <br />difficulty and cost of preparation." <br />