Impact of Global Changes on Mountains: Case Study of Brazil - Impact of Global Changes on Mountains: Responses and Adaptation - page 486

of the technicians in charge of the analysis is used to estimate the
probability of destructive events and their potential consequences.
• Evaluation of the potential consequences of each sector (number of
houses liable to destruction). The consequences are evaluated in terms
of number of houses that can be destroyed in case of occurrence of
instability processes. In the case of a risk analysis of a qualitative nature,
the estimate of the consequences of destructive events is performed
through the trial of the charge of technical analysis. The analysis
procedure involves:
° Evaluation of the possible ways of developing the active destructive
process (volumes mobilized, trajectories of the debris, areas of
outreach, etc.); and
° Estimates of the number of houses in the area with a risk of being
destroyed in case of occurrence of various forms of development of
the destabilization process.
• Presentation of the results obtained. The results of the risk zoning,
which must be synthesized into maps, aerial photographs and tables,
include:
° The delimitation of areas of risk and its cartographic representation;
° The description of the process of destabilization;
° The level of susceptibility of the sector and;
° The number of houses liable to destruction.
In the qualitative risk analysis, the probability of destructive events
(disasters) is assessed subjectively and expressed in literal terms (very high,
high, medium or low). Since the probability of occurrence of the destructive
process is a function of the time period considered, it is recommended to
consider in the risk analysis a period of not less than one year, comprising
at least one rainy season. Thus, when estimating the destructive events
probability, the technicians in charge of the analysis assess the probability
of a destructive event possible during an episode of intense and prolonged
rainfall. Other periods of validity of the mapping may be adopted, adjusting
for risk assessments of such a period, which should be explicit in the
technical report. It is recommended that the study should not include more
than a 10 years time period.
The proposed procedure comprises:
• The qualitative evaluation of the probability of occurrence of the
destructive process in the course of an episode of intense and prolonged
rainfall, held from the topographic features of human interventions,
geological and geotechnical characteristics of the underground site,
the indicators of instability, of evidence of earlier (past) destructive
occurrences of events and interviews with residents and;