B. Elements defining the significance of landslide activity
1. The toll in terms of human life, lost to landslides, represents a special element to significance. It is a cost which should be represented in addition to monetary costs to define significance. Injuries due to landslides should be represented along with fatalities.
2. Direct costs are those which involve actual physical damage and (or) are related to restoration costs to structures and land impacted by a landslide.
. . . a. Physical damage would include the loss of agricultural crops as well as the value of destroyed structures.
. . . b. Restoration costs are limited to the reestablishment of structures, other improvements, and the land to the same conditions and degree of usefulness as prior to the landslide.
3. Indirect costs are any costs associated with the landslide which are not direct.
. . . a. Relocation of structures or roads would be an indirect cost as would measures taken to prevent or mitigate additional damage.
. . . b. A major indirect cost is the effect on economic production. Lost wages due to the inability to reach work due to a landslide-closed road, tax losses due to decreased property value, such secondary physical effects as reduced crop production of affected slopes or silting of irrigation systems are all indirect costs to economic production.
C. Methods for determining significance
1. For the area being examined, significance should be assessed in conjunction with an inventory of past landslides or after such an inventory is completed.
2. Government agency personnel should be contacted. Through interviews and review of records, costs can be compiled for public works, agriculture, and other affected sectors.
3. Historical records held by churches, community groups, and private companies should be consulted as well as old newspapers. It may be worthwhile to interview residents where a landslide occurred to find out about unrecorded affects or details.
4. Developing a complete cost accounting may require estimation. The value of a specific crop may be generally known. By finding out the amount of crop damaged by landslides and relating that to the typical or average value for that crop, the crop loss can be determined.
5. Report the economic impact of individual landslides according to the IAEG format (WP/WLI, 1990, 1991).