THE SIGNIFICANCE OF LANDSLIDE ACTIVITY
OBJECTIVE: Participants will recognize the effects which make landslide activity significant or insignificant and be familiar with ways to determine significance.
CONTENTS:
A. Significance of landslide activity
1. Significance is the degree to which a specific hazard has impacted the natural and man-made environment. It would include loss of life, property damage, affect on critical infrastructure, and interference with economic production.
. . . a. The period of time over which the losses from a hazard are examined will influence significance.
. . . b. Some individual landslides can clearly represent significant losses - Nevado Huascaran avalanches (Peru) and Nevado del Ruiz lahars (Columbia).
. . . c. More often, individual landslides are not very significant. It is easy to be unaware of a significant loss over time due to the cumulative or additive effect of losses from smaller landslides.
2. Significance permits differentiating between future actions which may save lives compared to actions which may protect property or preserve essential services. The benefits of applying resources to avoid a future landslide can be compared to those for using the same resources in another economic function.
3. Public action to reduce losses from landslides starts with a fuller understanding for cost of failing to take action. When studied, the losses due to landslides:
. . . a. are much greater than expected for both the private and public sectors.
. . . b. Public officials are commonly unaware of the magnitude of these losses. The absence of any centralized recording of such information seems often to be the reasons for this lack of awareness.
. . . c. Landslides often coincide with such other hazards as floods, earthquakes, and volcanic eruptions. Much landslide damage is under-reported because it is attributed to these other hazards.
. . . d. Incompleteness or unavailability of records will result in lower estimates of losses than are actually incurred. Where this problem with records exists, the losses need to be identified as being the minimum losses.