**Disaster Risk Assessment Developing a Perceived Comprehensive Disaster Risk Index: The Cases of Three Chilean Cities**

Carmen Paz Castro, Juan Pablo Sarmiento and Claudio Garuti

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/62994

#### **Abstract**

A significant increase in the impacts caused by extreme events, of both natural and anthropogenic origin, has been observed in recent decades at a global scale. Chile is no exception to this dynamic. Hazards of various origins and their interactions with socioeconomic, urban, and demographic changes, combined with governance issues have led to a significant risk increase. An accurate assessment of this risk is a significantly complex problem and a holistic approach is required. To address this issue, a multi‐ criteria decision model has been designed, using the analytic hierarchy process (AHP), which includes qualitative and quantitative variables. The model can be adapted to different contexts, generating a comparable metrics (commensurable) for different cities. The three cities analyzed in this study (Iquique, Puerto Montt, and Puerto Varas) show different levels of risks as a result of a synergic and dynamic combination of factors related not only with natural and physical conditions but also particularly with the variables related to social vulnerability and resilience capacity.

**Keywords:** Disaster Risk Assessment, Comprehensive Disaster Risk Index, AHP, Commensurability, Risk Perception

### **1. Introduction**

In Chile, the study of risks generates special interest as it is one of the countries with the highest seismic activity around the world. Furthermore, it is exposed to hydro‐meteorological haz‐ ards, volcanic activity, and tsunamis, among others. Recently, the interest for research on risk

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assessment and improvement in managing risk has increased notably after the impacts produced by the February 27, 2010 earthquake followed by tsunami. The disaster which affected great parts of the national territory revealed not only the high exposure of the country to the hazard but also the high vulnerability in its various dimensions. The complexity and relevance of the theme deserve special attention to better understand the factors involved in the risk equation and the ability to face future events in better conditions.

More than a decade ago, Lavell (2003) said that disaster corresponds to the materialization of the pre‐existing risks in a society, which involve multiple dimensions. Risks should be identified and evaluated urgently in order to take action, going beyond structural measures aimed at reducing the hazard, addressing aspects related to the reduction of vulnerability and exposure of the population and their assets (Siddayao et al., 2014).

In this sense, new determinants that explain the risk conditions in Chile have been mainly associated with changes in the development model of economic globalization followed in recent decades which have brought immense territorial changes. More recently, the climate change scenario, considered an amplifier of extreme events risk, has generated a need for new mitigation and adaptation strategies geared toward an increase in the resilience of the population living in specific territories.

In this context, the research questions that have been raised in this study relate to the issues described by Wilches Chaux (1993) about how risks arise, grow, and accumulate in a particular context. Later, a comprehensive multi‐sectoral approach was introduced to improve disaster planning and build more resilient communities (Folke et al., 2002; Walker et al., 2002 in Henly‐ Shepard et al., 2015:110). Our research emphasizes the need to examine the interactions of the natural and anthropogenic phenomena which constitute the risk in a study area, and the analysis of the dynamics and trends in the construction of risk.

Our study methods are based on the analysis of data from previous research of the authors, the characteristics of the natural physical system in which the community is located, the perspective of evaluation processes that can become threatening, and the population vulner‐ ability and resilience. Risk assessment, the main objective of this research, was based on the analysis of the three variables: hazard (H), vulnerability, and exposure (E). It was performed by applying multi‐models and using the analytic hierarchy process (AHP) method (Saaty, 1980). The results allowed the definition of risk areas hierarchy in the three cities considered: Iquique, Puerto Varas, and Puerto Montt. The outcomes of this study will allow, at a later stage, the proposal of areas for protection and occupancy restriction in the territory.
