A Risk Analysis and Sustainability Approach to Natural Disaster Assessment and Mitigation Philosophy in the World
Natural disasters represent a widespread problem in the world. It is also an increasing problem for a sustainable world in absolute terms, social and economic, as will be shown below. This is the reason why the United Nations have declared the Internation
- PDF / 3,541,056 Bytes
- 25 Pages / 439.37 x 666.142 pts Page_size
- 67 Downloads / 205 Views
A Risk Analysis and Sustainability Approach to Natural Disaster Assessment and Mitigation Philosophy in the World F. J. Ayala-Carcedo
17.1
Introduction Natural disasters represent a widespread problem in the world. It is also an increasing problem for a sustainable world in absolute terms, social and economic, as will be shown below. This is the reason why the United Nations have declared the International Decade for Natural Disaster Reduction (IDNDR) 1990-2000. The main objective of scientific and technological research in natural disasters is mitigation. Mitigation, 'the measures taken independent from an emergency situation or actual disaster' (National Research Council 1994), must emphasise the preventive measures, because efficiency of emergency measures, in general, is very limited due to the avoidance of human and economic losses. The theoretical tool for a rational preventive mitigation is called risk analysis. Risk analysis, as shown in Fig. 17.1, has three stages: (a) risk factor analysis, (b) risk assessment, and (c) risk reduction analysis. Natural risk is the expected loss due to the action of a natural hazard. If we consider expected human losses, we have the so-called societal risk, with several types associated with the expected dead, injured, homeless, and unemployed; if we consider expected economic losses, we have economic risk, with several kinds associated with structural damage, content damage, benefit loss and so ono The existence of natural risks is a consequence of the existence of all the risk factors (Ayala-Carcedo 1993): hazard (with a severity or intensity and a probability of occurrence), exposure (of people or goods) and a vulnerability of this exposure, and a degree ofloss from o (no damage) to 1 (destruction or dead). Only when all the risk fac tors exist is there is risk or a conceptual reality (Fig. 17.2). In a simplified quantitative way, risk may be expressed as: R=IPVE
with R = risk (expected annuallosses); P = annual probability of occurrence; V = vulnerability (0-1); E = exposure. Obviously, preventive measures pretent risk mitigation, the preventive way to avoid dis as ters. The exploitation of the results of risk analysis with organisational, financial and management measures is called risk management (for instance Kauf 1978). Most of the approaches of natural sciences and engineering to the problem are hazard approaches, studying both severity and probability. Risk analysis is a global approach, including social sciences. This approach is more convenient from the point R. Casale et al. (eds.), Natural Disasters and Sustainable Development © Springer-Verlag Berlin Heidelberg 2004
F.
27 2
J. Ayala-Carcedo
RISK ANALYSIS !
I I
II
Hazard analysis .. Serverity .. Probability
IJ
RISK FAGOR ANALYSIS
RISK FACTOR MAPS
II
Exposure analysis Social Economic
Vulnerabilityanalysis Social Economic
t
I
1J
RISK ASSESSMENT
RISK = expected loss
R= LPxExV
R=Risk P = Probability E =Exposure V =Vulnerability (0- 1)
I O O O O
Social risk
I
I
Deads Injured Homeless Une
Data Loading...
