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The Study of the Urban Safety Network for Disaster in Iquique, Chile

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Chile has a long history of earthquakes and tsunamis and as a result the country has developed a strict regulation system that allow for an adequate response in case of earthquakes. On the other hand, the responses to tsunami events are still in development, especially after the 2010 earthquake and tsunami. The city of Iquique, that suffered an earthquake and minor tsunami in 2014, presents a challenge for a potential tsunami, as large areas could suffer severe damage, with inundations of 5-10 meters. Even more, in many cases the distances between the shore and the security areas are extremely long, generating excessive evacuation times and risk for the population. This paper examines Iquique and its potential tsunami scenarios, identifying and locating its weaknesses and possible improvements through a study of its evacuation routes, safety areas and potentially inundated zones in case of tsunami. This evaluation can help us achieve a clearer picture of Iquique, and a better understanding of the requirements of other similar Chilean coastal cities from an urban design perspective. Finally, this paper explores the addition of improvements to the urban safety network, particularly a system of vertical evacuation structures that could complement the existing situation.
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The Study of the Urban Safety Network for Disaster in Iquique, Chile
Sebastián, Laclabere Arenas1, Mamiko, Fujiyama2 and Toshikazu, Ishida3
1 Graduate Student, Department of Architecture and Building Science, Tohoku University, Japan
2Assistant Professor, Department of Architecture and Building Science, Tohoku University, Japan
3Professor, Department of Architecture and Building Science, Tohoku University, Japan
Abstract
Chile has a long history of earthquakes and tsunamis and as a result the country has developed a strict
regulation system that allow for an adequate response in case of earthquakes. On the other hand, the
responses to tsunami events are still in development, especially after the 2010 earthquake and tsunami.
The city of Iquique, that suffered an earthquake and minor tsunami in 2014, presents a challenge for a
potential tsunami, as large areas could suffer severe damage, with inundations of 5-10 meters. Even more, in
many cases the distances between the shore and the security areas are extremely long, generating excessive
evacuation times and risk for the population.
This paper examines Iquique and its potential tsunami scenarios, identifying and locating its weaknesses and
possible improvements through a study of its evacuation routes, safety areas and potentially inundated zones
in case of tsunami. This evaluation can help us achieve a clearer picture of Iquique, and a better
understanding of the requirements of other similar Chilean coastal cities from an urban design perspective.
Finally, this paper explores the addition of improvements to the urban safety network, particularly a system
of vertical evacuation structures that could complement the existing situation.
Keywords: Emergency, Tsunami, Resilient urban design, Evacuation structures, Public space
1. Introduction
Chile is located in the southern end of South
America, along the “Pacific Ring of Fire”, as a
result the country has been constantly affected by
earthquakes throughout its history. Barrientos
(2007). As a response to this situation the country
has developed a strict regulation system that has
strongly influenced the development of architecture,
urban design and engineering. In recent decades the
earthquake preparation has reached a very high
standard, but tsunami preparation remains in a
lower level and has started to be the focus of
serious government efforts to improve them,
especially after the 2010 earthquake and tsunami,
where several coastal cities suffered serious tsunami
damage.
1.1. Earthquakes: History and regulations
As was already mentioned, Chile has a long and
constant history of seismic events, including large
scale earthquakes and tsunamis, with the first
recorded events going back to 1647, in the middle
of the Spanish colonial period. Some of the most
important events recorded in the history of the
world have occurred in Chile (Table 1), like the
1922 Vallenar earthquake with a magnitude of
8.5Mw, the 1960 Valdivia earthquake, with a
magnitude of 9.5Mw, the biggest earthquake ever
recorded and the recent and highly destructive 27F
earthquake with a magnitude of 8.8Mw, that
affected the whole central and south areas of the
country. This constant succession of seismic events
has shaped the character and culture of Chile, and
also its architectural and urban expression.
Table 1. Earthquakes in Chile by magnitude
Earthquake
Magnitude (Mw)
Vallenar / 1922
8.6Mw
Valdivia / 1960
9.5Mw
San Antonio / 1985
8.0Mw
27F / 2010
8.8Mw
Considering this context of constant natural
disasters, the regulatory and technical framework
has adapted accordingly over the years, with the
first architecture and construction regulations
appearing in 1929, and the first earthquake focused
regulations appearing in 1972 as a response to the
Valdivia earthquake of 1960, 12 years before.
Regulations have been updated after each major
event, with the last important modifications being
developed after the 2010 27F earthquake, Herrman
(2016), this time not only including earthquake
Sebastián Laclabere Arenas, Graduate student,
Department of Architecture and building science,
Tohoku University.
e-mail: sebastian.laclabere@gmail.com
related regulations, but also considering for the first
time a tsunami event specific regulations.
After the 27F earthquake the government started
a process of both reconstructing the damaged areas
and improving the disaster preparedness of all of
the coastal cities in the country, both affected and
not yet affected by the tsunami, to increase the
response quality in case of a new event.
1.2. Seismic context of the north of Chile
In recent years, many studies have suggested the
latent possibility of a large mega thrust earthquake
in the north area of the country. The main reason
that explains this possibility is that the northern
Chilesouthern Peru seismic gap last broke in 1877
in a great earthquake (8.8 Mw) that ruptured from
south of Arica to the Mejillones peninsula.
The reported historical recurrence interval for the
past 500 years in this region has been estimated at
111-144 years, making it probably the most mature
seismic gap along the South American plate
boundary. In the past two decades the two adjacent
segments south and north broke in the Mw 8.1
Antofagasta earthquake of 1995 and the Mw 8.4
Arequipa earthquake of 2001 in southern Peru.
Schurr et al. (2014)
In the year 2007, an international monitoring
effort was started by a series of Chilean and
European universities and institutions, called
Integrated Plate Boundary Observatory Chile
(IPOC). This joint monitoring program follows the
changes and evolution of this specific area in an
effort to improve the knowledge and preparedness
in case of a large scale seismic event.
This endangered area has a large number of cities
and towns spread throughout, with the three biggest
and most populated areas being Antofagasta, Arica
and Iquique.
1.3. Case of study: Iquique
As case of study we will focus on the city of
Iquique, located in the extreme north of the country
that suffered a serious earthquake and minor
tsunami in the year 2014, which presents a
particularly serious challenge from the viewpoint of
a potential tsunami. Iquique is located on a narrow
coastal plain, adjacent to a very high coastal
mountain range, with heights of over 600mts.
Weather is of coastal desert type, dry and hot with
no rain while the population is 180,601 according to
the last census. Also of note is the nearby location
of the adjacent city of Alto Hospicio, with a
population of 112,142, together both cities form the
Greater Iquique area. INE (2012).
The city also presents a particular context both in
terms of urban and architectural design, largely
influenced by its role as a mining and industrial port
during the 19th century, the great number of foreign
immigrants it received and its evolution process
until currently becoming a commercial and touristic
hot spot not only for the country but also in South
America. Gurovich (2005)
2. Methods
This chapter is based on the analysis of one case
of study, the city of Iquique, and the evaluation of
its urban safety network, mainly through the
analysis of potential inundation maps and
evacuation times based on hypothetical scenarios
developed by previous researches and finally
proposing a new layer of vertical evacuation
structures that could improve the performance and
the quality of life of the city both in tsunami
disaster and daily life situations.
2.1. Existing Urban safety network
After the 27F earthquake and tsunami and its
fatal consequences, the Chilean government and its
technical agencies have focused on producing
updated evacuation maps for every important
coastal city and town in the country. All of these
evacuation maps present 3 main elements:
evacuation routes, safety areas and a security line.
Evacuation routes are the roads and streets that
should be used for evacuation to higher areas.
Safety areas are places, located over the minimum
required height to avoid tsunamis where the
community should gather in case of these events, to
organize themselves, wait for information and help
from government sources and NGO’s. The security
line is a line or border that defines from what point
on the height is enough and the area becomes safe
in case of tsunami.
Iquique’s current urban safety network as defined
by local authorities (Fig.1) consists of 43
evacuation routes (orange lines) and 68 safety areas
(blue dots), ONEMI (2017) to receive a population
in evacuation areas of 108.881 people.
The current safety network presents two major
problems: first, in some areas, the distance between
the ocean and the safety areas is too long, second
the safety areas don’t have any sort of equipment or
shelter to properly accommodate the evacuated
population, they are just empty open spaces.
Fig.1. Current Urban Safety Network Iquique
2.2. Potential inundation areas
With regards to the estimation of the possible
effects a tsunami could have on the city of Iquique,
simulations have been conducted in recent studies
that can paint an accurate picture of the possible
consequences of a large scale earthquake and
tsunami.
As a part of the “SATREPS Chile Tsunami
Project” developed by SATREPS and JICA in the
year 2016, a simulation for tsunami events in
Iquique was conducted using the TUNAMI N2
software developed by Tohoku University.
These simulations consider three different
scenarios: Scenario A (8.8Mw) Scenario B (9.0Mw)
and Scenario C (8.9Mw) and are based on previous
studies by Yagi et al., (2014) who proposed the
rupture scenarios and Chlieh et al. (2011) who
calculated the seismic potential. (SATREPS, 2016)
We can note that the results of the simulation for
all three scenarios result in serious tsunami
inundations along the coastal area of the city.
Scenarios A (8.8Mw) and C (8.9Mw) present
maximum inundations of between 2 and 5 meters
deep in specific places, but general inundations
between 0.5 and 2 meters deep. Scenario B is the
worst case scenario, with much extended
inundations between 2 and 5 meters deep and
maximum inundations of between 5 and 10 meters
in some specific areas. (Fig.2)
According to the simulations in this study, the
first wave is estimated to reach the shore after only
20 minutes, with a second and third waver arriving
after 60 minutes of the earthquake.
Fig.2. Urban safety network analysis diagrams.
2.3. Potential evacuation times
Through the simulation of diverse scenarios we
have already observed how extended areas of the
city of Iquique would be deeply affected in case of
tsunami. With this information, is also important to
analyze the evacuation performance of the city to
face an event of these characteristics.
To analyze the evacuation performance of
Iquique we will take as a reference a series of
simulations conducted to predict the evacuation
times in case of a mega thrust tsunami by Leon and
March. This research considers two different
computer generated models:
The first model is aimed to analyze the urban
configuration of the city, the way the different
evacuation spaces (streets, squares, alleys, etc.)
become connected to each other and can
successfully conduct the population from their
location to safe ground.
The second developed model consists of an agent
based model, the outcome of this process, after a
certain number of iterations in a timeline allows to
calculate the required time to remove all the agents
from an endangered area, in this case, by tsunami.
In the model, every evacuee in the tsunami
vulnerable area was provided with a shortest route
to follow, a pedestrian evacuation speed (1.4 m/s),
and three speed-decreasing rules.
The study of these two models proves that the
city of Iquique has serious problems with regards to
their evacuation times, sometimes even surpassing
35 minutes, due to the long distance between the
shore and the safety areas. León and March (2015)
3. Results and discussion
Through the simulation of diverse scenarios we
have already observed how extended areas of the
city of Iquique would be deeply affected in case of
tsunami, additionally we can also see that the
evacuation performance of the city in these types of
events presents some serious problems.
Considering this background it seems important
to study possible ways to improve the response of
the city in case of a tsunami emergency, especially
through the addition of a new layer to the existing
urban safety network that can complement and
improve its performance: A system of vertical
evacuation structures.
3.1. Improvements to the safety network
In case of tsunami events, the first priority is
always horizontal evacuation towards higher
ground, but this is not always possible because of
the long distances and the short warning times
particularly in the case of near-field tsunamis. In
these cases, sheltering-in-place or sheltering
near-place” through the use of vertical evacuation
structures may be an alternative way to evacuate
from the dangers of a tsunami. FEMA (2008)
Currently in Chile there are no examples of these
type of structures, but successful examples of
vertical evacuation structures have been developed
in Japan, the west coast of the U.S.A and in recent
years in Southeast Asian countries like Indonesia,
particularly in the region of Banda Aceh after the
2004 Indian Ocean earthquake and tsunami. Kim et
al. (2015).
Fig.3. Current safety zone Iquique /
Vertical evacuation tower in Kochi, Japan
https://sipse.com/mundo/continua-temblando-en-chile-registran
-56-replicas-80812.html
http://www.g-mark.org/award/describe/44371?locale=en
Considering Iquique is a city not yet affected by
a natural disaster, it’s important to find ways to
establish interventions and improvements while the
city continues its daily and regular life, as such, the
proposal of this vertical evacuation network should
consider the following 3 design principles:
Flexibility and duality:
One of the main concerns when designing
vertical evacuation devices is the problem of use:
How can we sustain a building that would be only
used in sporadic situations such as natural disasters?
The key element here is the need for flexible spaces
that can change when it’s needed and hold a
diversity of uses, not only during natural disasters
but also during daily life situations, making these
vertical evacuation devices part of the urban tissue
and the daily life of the citizens.
Daily life uses for these structures should be in
close relation to their immediate context, and hold a
wide variety of programs, such as community
centers, commerce, tourist information, cultural,
and religious activities.
Fig.4. Daily life / Emergency dual use of space
Proposal by the author
Self-sustainability:
Another important problem of the current safety
areas is their lack of hygienic services and shelter,
in most cases they are just open spaces without any
type of program. Following the latest government
guidelines, MINVU, ONEMI (2017), the vertical
evacuation structures should provide the citizens
with the minimum comfort, hygiene and shelter
needed for at least the first 12 hours, this should
also consider energetic and sanitary self-sufficiency
with the use of renewable resources
Punctual small scale interventions:
As previously stated, the city of Iquique has not
been affected by tsunami events in recent decades,
as such, it’s a fully functional city and this makes it
difficult to make large scale interventions, due to
the lack of space. To face this problem the vertical
evacuation devices should maintain a controlled
and minimum scale, to work in between small open
spaces as a sort of urban acupuncture intervention.
Fig.5. Vertical evacuation structure in Iquique.
Proposal by the author
4. Conclusions
This paper attempts to achieve two main
objectives: First, to understand and establish a clear
vision of the Chilean reality with regards to
earthquakes and tsunamis, understanding both its
recurrence over time and how they have influenced
the development of architecture and its regulations.
A second objective is to understand the current
situation of the city of Iquique and its position in
the heart of a highly vulnerable area with regards to
a future large scale earthquake and tsunami event.
This research then analyzes the city from various
viewpoints, using as a starting point a series of
previous researches that simulate the response of
the city in the case of a large scale tsunami event.
After establishing a general appreciation of the
potential response of the city and its already
existing urban safety network, the research attempts
to suggest a potential improvement, with the
incorporation of a system of vertical evacuation
structures that could reduce the evacuation times for
people in the most vulnerable areas.
As a city that has not been affected by natural
disasters in recent decades, Iquique presents an
interesting challenge as to how to intervene in a
functioning context without the benefit of the post
disaster “tabula rasa”. To face this challenge this
paper proposes 3 design recommendations that
could help achieve a successful proposal: Dual use
and flexibility, self-sustainability and localized
small scale interventions.
Working in between the urban tissue, establishing
connections and relations both with the preexisting
buildings and its users seems to be the key to a
successful intervention that can improve the current
situation of the city, both for times of emergency
and also the general life standard of the city, its
public spaces and users.
5. References
1) Barrientos, S.E. (2007) Earthquakes in Chile.
Geological Society Special Publication.
2) Chlieh, M., Perfettini, H., Tavera, H., Avouac,
J-P., Remy, D., Nocquet J-M., Rolandone, F.,
Bondoux F., Gabalda, G., Bonvalot, S. (2011)
Interseismic coupling potential along the Central
Andes subduction zone. Journal of Geophysics
research, vol. 116, B12405,
doi:10.1029/2010JB008166.
3) FEMA. (2009) Vertical Evacuation from
Tsunamis: A Guide for Community Officials.
FEMA P646A.
4) Gurovich, A. (2005) La ciudad de Iquique.
Revista de arquitectura N°10 (11), 8-13.
5) Herrman, M. (2016). The role of Urban Planning
in Mitigating Tsunami in Chile after February
27th, 2010. Revista de Urbanismo N° 34, 20-33.
6) León, J., March, A. (2016) An urban form
response to disaster vulnerability: Improving
tsunami evacuation in Iquique, Chile.
Environment and Planning B: Planning and
Design 43(5), 826847.
7) MINVU, ONEMI, CIGIDEN. (2017) Guía de
referencia para sistemas de evacuación
comunales por tsunami. ISBN:
978-956-9432-16-3, Santiago de Chile.
8) SATREPS Chile tsunami project. (2015) Guía
para la Estimación de Peligro de Tsunami.
Research Project on Enhancement of
Technology to Develop Tsunami-Resilient
Community. Santiago de Chile
9) Schurr, B., Asch, G., Hainzl, S., Bedford, J.,
Hoechner, A., Palo, M., Wang, R., Moreno, M.,
Bartsch, M., Zhang, Y., Oncken, O., Tilmann, F.,
Dahm, T., Victor, P., Barrientos, S., Vilotte, J.
(2014) Gradual unlocking of plate boundary
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Aránguiz, R. (2014). Tsunami hazard estimation:
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11) Yuzal, H., Kim, K., Pant, P., Yamashita, E.
(2015) Tsunami evacuation buildings (TEBs)
and evacuation planning in Banda Aceh,
Indonesia. Transportation Research Board
annual meeting.
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