An urban design framework for tsunami evacuation safety

An urban design framework for tsunami
evacuation safety: a case study of two
5th International Disaster and Risk Conference IDRC 2014
‘Integrative Risk Management - The role of science, technology & practice‘ • 24-28 August 2014 • Davos • Switzerland
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Chilean cities
Jorge León (PhD Candidate 2011-2014) /
Associate Professor Alan March /
University of Melbourne / Australia

Miyagi prefecture, Japan. 11th of March 2011. Source: Reuters.
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Valparaíso, Chile. 11th of March 2010. Source:
YouTube.
Antofagasta, Chile. 19th of August 2011.
Source: La Estrella de Antofagasta. Iquique, Chile. 16th of March 2014. Source: El Mercurio.

background methodology outcomes discussion
Disaster resilience, cities, and urban morphology
• The predominant location of actual and potential disasters has shifted to urban areas (Brown, 2012,
Wamsler, 2014).
• Urban planning can improve a city’s resilience to disasters, via its ability to spatially integrate multi-dimensional
aspects affecting disaster risk reduction (Burby, 1998).
• It has been difficult to translate this aim into practice (March and León, 2013, Wamsler, 2014).
• Limited research on the links between resilience and the design of urban form.
• Few studies on understanding the role of urban morphology during disaster’s response phases (Allan et
al., 2013).
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• This is especially critical in the case of a near-field tsunami, whose first waves could arrive between to the
coast 20 to 25 minutes after an earthquake.

Tsunami risk reduction in coastal communities
• Efforts have been concentrated in three main areas (Eisner, 2005, Shuto, 2005, Murata et al., 2010):
1) Large civil-engineered
countermeasures (e.g.
breakwaters, seawalls,
sea gates)
2) Urban land use and built
environment (e.g.
identification of inundation
areas, relocation of dwellings
and key activities, improved
building codes, etc.)
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3) Emergency readiness
(forecast and warning
systems, evacuation
preparedness, evacuation
simulation, etc.)
Involve considerable technical
and economic resources,
have not been widely applied
Require long-term changes, not
typically addressing population-focussed
tsunami-response
activities
The urban realm is usually
approached as a relatively fixed
context.
?
What is the role of urban morphology in
achieving more effective and safer pedestrian
evacuations during near-field tsunamis?
In case of a tsunami, evacuation “is
the most important and effective
method to save human lives”
(Shuto, 2005: 8)

Case studies: Iquique and Talcahuano, Chile
IQUIQUE
TALCAHUANO
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Source: John Nelson, IDV Solutions (2012) Source: Google Earth (2014)

Phases of the study
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Existing conditions
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Micro-scale (evacuees’ experience) Macro-scale (urban configuration)
Weighted overlay analysis of current evacuation vulnerability, developed in ArcGIS Agent-based evacuation model of Iquique, developed in Agent Analyst
Meeting with members of local community and
emergency stakeholders, Talcahuano Survey of an identified priority evacuation route, Talcahuano

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Intervention: macro-scale (urban configuration)
Synthesis of proposed
interventions for Iquique
and Talcahuano

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Intervention: micro-scale (evacuees’ experience)

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Analysis
Configuration analysis of
proposed interventions
(Network Analyst)
Agent-based analysis of
proposed interventions (Agent
Analyst)

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Tsunami and evacuation critical issues
1. Long recurrence between devastating events
• Makes difficult to define a risk context according to previous experiences (e.g. lack of reliable
archives).
• Hinders long-term risk reduction efforts (e.g. by diminishing public and political awareness).
• Makes difficult to maintain a ready-to-function state across emergency response and relief
institutions.
2. Great earthquakes as factors of discontinuity
• Great earthquakes (i.e. M8.0 or higher) have the potential to trigger ‘cascading consequences’
and ‘sequential failures’ (Alesch and Siembieda, 2012) throughout the urban systems.
• Essential services (e.g. electricity, communication, etc.) are commonly interrupted, hindering
both the authorities and population’s responses to the emergency.
3. Location inertia
• Tsunami-vulnerable urban locations are the historical outcome of interrelated socio-economic
(e.g. city foundation policies) and geophysical conditions (e.g. availability of plain land). Coastal
locations are especially appealing (NTHMP, 2001).
• Relocation has been proved a difficult process especially in developing contexts, due to the
existing social ecologies, economic bonds, and the common informal re-occupation of the newly
vacant land (Mehrotra, 2014).

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Tsunami and evacuation critical issues
4. The influence of urban morphology characteristics
• Three basic groups of elements determine the role of urban morphology during tsunami
evacuations: street pattern arrangements (e.g. orthogonal vs. hierarchical grids), built
environment quality (e.g. formal vs. informal areas), and existing notorious natural or manmade
features (e.g. for assembly or wayfinding purposes).
5. Socio-cultural traits
• Tsunami awareness across the population might have steep differences, delaying or making
difficult proper responses.
• Several cultural threats might hinder the evacuation process: incorrect preconceptions, lack of
information and guidance from institutions, incorrect behaviours (e.g. delayed evacuation, use of
car, wrong selection of routes, lack of family evacuation plans, etc.), and antisocial behaviours
(e.g. looting).

Urban design principles for tsunami evacuation:
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What is the role of urban morphology in achieving more effective and safer pedestrian
evacuations during near-field tsunamis?
1. Closeness
• Reduce to the greatest possible extent the average distance between the evacuees’ locations and
the safe assembly areas, by shortening evacuation routes or by creating new safe spots.
2. Rapidity
• Allow a fast and fluid movement of evacuees throughout all the routes, by increasing the
availability of pedestrian space, by guaranteeing proper built environment’s qualities, and by a
careful placement of all the elements that might cause blockages (e.g. urban furniture).
3. Safety
• Ensure sufficient pedestrian space to prevent reduced speeds or stagnation.
• Built environment should avoid every element susceptible of serious earthquake damage (e.g.
facades, hanging billboards) and include especially-designed elements (e.g. urban furniture
without sharp edges).
• Provide clear separations between vehicular and pedestrian traffics.

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4. Redundancy
• Increase the number of all the elements belonging to the evacuation network: priority routes, safe
assembly areas, access points to these areas, etc.
• Duplicate all the critical bottlenecks susceptible of earthquake damage, such as bridges and pedestrian
runways.
5. Plausibility
• Mainstream the proposed recommendations into daily planning practice (Wamsler 2014), contributing
to bridge the gap between the cultures of normalcy and the state of exception (Beck, 2009).
• The main aim of design suggestions should be the provision of liveable public spaces, designed with
the highest possible built standards, capable of being enjoyed by the population especially during non-emergency
times.
6. Autonomy
• Enhance the capacity of the urban environment to support evacuees’ responses in absence of official
guidance, by increasing physical continuity and wayfinding characteristics of evacuation routes.
7. Memory
• Use the persistence of the built environment to support long-term maintenance of a tsunami culture
among the population.
• Create urban places aimed at remembering past disasters (e.g. memorials, parks).
• Use toponymy to identify urban features with their role during a possible emergency.

Added value for the Post 2015 Framework for
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Disaster Risk Reduction
• How did your work support the implementation of the Hyogo Framework for
Action:
– Our research draws into the three strategic goals of the Hyogo Framework for Action.
– We showed how urban designers and planners can use and adapt existing risk knowledge sets
into urban morphology changes, for sustainable city development policies.
– We aim at strengthening institutional resilience to hazards, by providing support and
quantitative leverage to planners and city officials when arguing for required changes in urban
form.
– We suggest urban morphology changes as a systematic tool for improving tsunami emergency
preparedness and response, by contributing to bridge the gap between ‘normal’ and
‘emergency’ times in the city (Beck, 2008).
• From your perspective what are the main gaps, needs and further steps to be
addressed in the Post 2015 Framework for Disaster Risk Reduction in
– Research: enhance efforts to understand the role of urban morphology in DRR.
– Education & Training: mainstream DRR across the different levels of urban form-related
disciplines.
– Implementation & Practice: alongside with strategic urban planning, unleash the potential of
‘retrofitting’ planning to increase resilience to disasters.
– Policy: strengthen the role of planners in governmental DRR policies (in a context where more
than 50% of the world population lives in cities).

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Thank you.

An urban design framework for tsunami evacuation safety

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