The following main points have been identified in the previous conceptual discussions (Sub‐chapters 2.1, 2.2, 2.3) which are relevant for this study:
• Potential use of vulnerability assessment for early warning interventions: the study argues that vulnerability assessment should also identify specific factors causing the lack of people´s response capability linked to early warning interventions to derive practical recommendations at the local level.
• Need for further incorporation of human cognitive factors in vulnerability assessment: the study argues that issues of perception related with specific hazard and risk reduction measures are crucial and are part of the decisive intrinsic factors that influence the effectiveness of vulnerability reduction in the long‐term.
• Limited linkage of the vulnerability concept with assessment with urban planning: the study argues that vulnerability assessment is an important element that should be integrated in urban planning, especially considering its continuous planning cycle.
• Potential use of vulnerability assessment as a tool to enhance synergy between emergency and urban planning, In this respect, the study argues that vulnerability assessment which is linked to disaster preparedness, such as early warning, may indicate specific needs required to be incorporated in the long‐term urban planning, thereby enhancing its synergy with emergency planning.
In the attempt of addressing those points in the conceptual framework, this section describes how the concept of vulnerability is applied in the context of tsunami early warning systems at the local level and linked with the urban planning scheme. Initially, the term vulnerability in this study was defined based on the UN/ISDR (2004) internationally accepted definition of vulnerability:
“The conditions determined by physical, social, economic and environmental factors or processes, which increase the susceptibility of a community to the impact of hazards; for positive factors, which increase the ability of people to cope with hazards.”
This means that people or the community are put at the centre, but the vulnerability assessment considers various factors (not only human conditions) that influence their susceptibility and coping capacity. Vulnerability in the context of this study does not encompass the overall vulnerability to tsunamis. Rather, it is formulated in the context of disaster preparedness to meet the objective of an effective people‐centred early warning at the local level and limited to thematic areas which are directly relevant to the interventions and specific goals of tsunami early warning. The potential impact or risk of
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concern is loss of lives (not including livelihoods), which should be reduced by early warning and timely evacuation to safe areas.
Despite the controversy, whether exposure may be treated as an independent component showing relationship between the system and the hazard component (Gallopin 2003; 2006), the study views exposure as part of vulnerability which represents an inventory of elements in an area in which hazard events may occur (Field et al. 2012; UN/ISDR 2009, e.g. the existence of various social groups in the endangered area. This is important to show on the one hand that exposure analysis includes the differentiation of exposed people by their susceptibility and response capacity (who, where, and why) and, on the other hand, to address the issue that development and intensification of elements (e.g.
urbanization) in the hazardous areas would increase the overall vulnerability of the people if there are no sufficient mechanisms in place to counteract those aggravating effects. In this context, this study proposes a modified definition of vulnerability as:
“The conditions which influence the level of exposure and capability of people to respond to the warning and conduct appropriate evacuation, and in the long term, to change those conditions and enhance their response capability.”
The BBC‐Framework (Sub‐chapter 2.1.1) is helpful as a basis for the development of the conceptual framework in this study because it provides guidance in visualizing the process of reducing vulnerability and altering its components as a feedback loop system linked to various interventions. Extending the basic ideas of the BBC‐Framework3, the vulnerability in the context of the tsunami early warning as defined above was incorporated to the model, (Figure 1).
The first block visualizes the current response capability of the people which is influenced by dynamic exposure and factors playing a role in the stages of early warning delivery at the local level up to people at risk taking action, namely access to warning, evacuation behaviour, and access to safe places. The component of dynamic exposure is visualized in a box that covers also the other components since it also determines the quantity and social constellation of the other components.
Dynamic exposure
The exposure of population to potential major tsunamis is strongly determined by the spatial distribution of the same. In the context of urban areas, the exposure of the people or population groups is dynamically determined by the spatial setting of the urban areas (the locations of various city functions where people are concentrated) and their daily activity patterns. The level of exposure will be higher the
3Initial vulnerability framework was developed jointly with the project partners in the first phase of the ”Last‐Mile – Evacuation“ research project in Birkmann et al. (2008) and its further development received inputs from Gebert (2011)
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more intensive the activities of the people in the potentially affected areas of the city are. Besides the settlement density, it is also important to consider the spatial distribution of city services and facilities.
Especially in urban settings, the spatial and temporal dynamics are often high. This is also linked with the mobility of the people to and from dangerous areas to conduct activities and results in dynamic exposure. The daily activity pattern of various population groups and household members may differ according to their role in the household and community as well as their available resources. Họgerstrand (1970; Pred 1981) suggested that every individual has a certain available time and resources that would limit their mobility. According to this concept, the mobility of the people is a combination of the availability of individual resources, locations as well as the accessibility of the locations, which is strongly linked with the urban land use (Họgerstrand 1970; Oòenbrỹgge and Haferburg 2005).
Access to safe places
Availability of evacuation routes and places which are accessible to the people exposed considering the short time frame of a tsunami arrival is very important. In the context of densely built cities, especially the street network and open areas passable by the people play a big role. In case of long horizontal evacuation distance, additional facilities like vertical evacuation shelters may be needed.
Access to the warning
More directly related to the early warning dissemination is the availability of media that can be used to deliver early warning and relevant information. Also, how these media are utilized in case of emergency determines the effectiveness of warning dissemination.
Evacuation behaviour
This component encompasses the understanding of and response to the early warning translated in the people’s evacuation behaviour: whether they sense the urgency and decide to conduct evacuation and how are they going to do it. Such factors can be observed in past events and are related to the people’s prior knowledge about evacuation and their perceptions (related with the next component).
Issues of perceptions related with vulnerability reduction
The separate component below people´s response capability addresses the issues of perception and links the above components with various interventions to reduce vulnerability. This implies that vulnerability reduction actions will be filtered out by the people depending on their subjective judgements. The attitude and motivation of the people to conduct protective or vulnerability reducing actions is influenced by various cognitive factors and may differ depending on socio‐economic characteristics.
Vulnerability reduction measures
This block represents various interventions that are necessary within urban planning, which should be planned and implemented in strong cooperation with emergency planning. The role of urban planning is crucial in various thematic components of the people’s vulnerability. As identified in the Table 2‐1, the
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role of urban planning are firstly in the considerations of hazard and risk in the overall formulation of goal and planning, integration of emergency related response interests, and support in infrastructure. In this scope, linkage of urban spatial and land‐use planning in controlling growth and use in the exposed areas considering the evacuation capability of the people as well as providing space and infrastructure for evacuation routes and facilities were examined. The link between urban planning with promoting appropriate evacuation behaviour, as well as emergency planning with exposure reduction, is initially assumed to be indirect but will be explored further in the case study.
Overall, this feedback loop system shows continuous changes of the components that should be dealt with in various interventions. It emphasizes the necessity of continuous vulnerability assessment and reduction.
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Figure 2-5 Conceptual framework of vulnerability in the context of tsunami early warning and evacuation
Source: own figure, initial ideas from BBC‐Framework, Birkmann et al. (2008) and Gebert (2011)
Vulnerability
Improvement of access to warning Improvement of
access to safe places
People´s exposure and lack of early warning response capability
Dynamic exposure
Spatial setting Activity/mobility
Access to the warning Availability of media
Effectiveness of media
Evacuation behaviour Past behaviour
Awareness &
knowledge Access to safe
places Evacuation road Evacuation shelters
Vulnerability reduction measures
Exposure monitoring and reduction
Promoting appropriate behaviour Human‐cognitive factors
Socio‐economic status
Issues of perception related with vulnerability reduction
Inundation areas Wave energy
Hazard
Major tsunamis
Estimated time of arrival
Event
Tsunami early warning system and supporting interventions
FEEDBACK Vulnerability assessment
Risk
Loss of lives during
major tsunami
events Emergency
response and planning
Ensuring sufficient response capability
considerations in development planning, integration of emergency response interests, support in infrastructure, risk communication
provision and maintenance of emergency facilities, disaster preparedness activities
emergency planning
urban planning
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3 Context of the Tsunami Early Warning and Risk Reduction in the City of Padang, Indonesia
After the Indian Ocean Tsunami event in December 2004, the attention of the international scientific and humanitarian community was drawn to the other endangered areas where major earthquakes and tsunamis may occur in the future. The city of Padang, West Sumatra, Indonesia (Figure 3‐1), was one point of concern, due to its huge seismic potential in the near future and the dense development of its low‐lying coastal areas. This chapter provides an overview of the context of Indonesia but particularly the city of Padang encompassing the existing earthquake and tsunami hazards, the spatial development of the city, as well as the institutional setting of the tsunami early warning system and urban planning in the area. This prior knowledge is useful to embed the conceptual framework developed in Chapter 2 and further on interpret the assessment results within the local context.
Figure 3-1 The city of Padang, West Sumatra, Indonesia
Source: Google Maps, 2013