Cities at the crucible of multiple historic and present dynamics

Scira Menoni and Funda Atun (POLIMI)

In the past cities used to take decades to build new areas, to transform a city centre, to introduce new infrastructures. In contemporary cities many forces drive change, including, recently, digital and communication technologies. Mobility has grown dramatically the possibility to expand cities much beyond their “natural” borders. Today’s cities may face much more rapid changes in terms of the pace of construction, creation of new networks and shift from one developmental model, such as industrial, to another, more service oriented.

Nevertheless, city vulnerability is not only the result of recent changes, even when they occur very rapidly; but also of past decisions, of trends that started long ago. Vulnerabilities in a city have accumulated over the course of time. If this is true for the past, it will be even more so in the future. Future vulnerabilities will be the result of today’s decisions mixed with changes in the natural, social, political and economic environments.

Different temporal dynamics unfold in cities: some are the result of long duration processes that accumulate over decades and centuries. They are the result of micro-level decisions or lack of decisions, of actions that are prescribed in city regulations or embedded in the non material culture of inhabitants.

Other dynamics reflect abrupt changes, due to the interruption of ordinary life, after a war, a disaster, a dramatic change such as the one that occurred with the industrial revolution, when old schemes were wiped off, destroying centennial walls to allocate more space for factories and urbanized peasants. Such deliberate changes include modifications in the city layout, patterns, with the introduction of new infrastructures, large palaces, new economic attractive centres.

Whilst planners have become familiar with the different dynamics in city landscapes of the past, they are far less aware of the potential of a catastrophic event that can change the conditions and image of a city beyond recognition, with the loss of those key referential places and buildings.

Whilst it is important to recognize past dynamics to reconstruct the decisions and events that have led to the current situation in terms of vulnerability and resilience, planners and city managers encounter difficulties in imagining future scenarios. Planners are not trained to foresee how the environment they are used to and in which they are prepared to be operational in case of disaster may change suddenly and abruptly. They are not used to recognizing the potential for abrupt future changes in an apparently stable landscape and in the natural features that are part of it. How cities change and evolve during a crisis still has to be fully understood and investigated; however it is evident that developing an understanding of this type is crucial in the disaster prevention phase, to avoid developing the most hazardous locations so as not to unduly increase exposure and vulnerability. For preparing for an emergency it is important to make civil protection and first respondents aware that references that they have placed on their maps that are part of the emergency plan may have changed or have been destroyed.

Vulnerability patterns produced by rapid urbanization: the case of Istanbul

The structural development history of Istanbul can improve our understanding of the effects of rapid urbanization on inherited vulnerabilities of cities. Changing national economic policies has had a distinctive effect on Istanbul’s economic, spatial and social structures. In the last period, the increase in vulnerability is defined due to large industrial areas in hazard-prone areas, increased density of people and buildings and low quality dwellings. After the 1980s, the percentage of Istanbul’s population in Turkey’s total population increased immensely. The number of buildings grew accordingly. Istanbul was a second level earthquake zone until 1996, then it became a first level earthquake zone. All the buildings constructed before 1997 were built according to the previous building code. As a result of these trends, the city has become more vulnerable to hazards.

Lessons learnt in today’s cities landscape

Cities, their identity and building techniques are partly influenced by their environment and the threat of hazards. People adapt the built environment to adjust to living with risks in places where they are frequently exposed to hazards.

These patterns become embedded in cultures over time. This accommodation is reflected in the design of buildings and the materials and construction techniques. Important to note however is that these architectures are the result of a whole range of socio-cultural factors, not just the threat of hazards.

This heritage serves a role in preserving local identity and personality, but also local knowledge; preserving heritage has educational purposes in awareness raising, as the layout of a city (plazas, avenues), the construction of buildings (Dordrecht’s ‘floating cellars’) and infrastructure (multiple escape routes) may reveal a logic that is often more in tune with urban exposure to natural hazards than today’s urban development.

In areas of the world where earthquakes present a frequent threat to people’s lives and assets, similar anti-seismic construction methods have evolved. Greg Bankoff identified at least three zones of identifiable earthquake resistant architecture: the Alpine-Himalayan belt, the Eastern Mediterranean, Southern Europe and the Himalayan arc. People living in these regions are culturally distinct but share a similar risk from earthquakes and their responses to the threat are similar.

Such seismic construction subcultures often use local materials, skills and resources. Traditional buildings usually consist of configurations and have a small number of storeys. A closer look at such (sub)cultures may help in vulnerability reduction and disaster mitigation. Examples that may be relevant for the EDUCEN project include, the göz dolmas and muskali dolmas technique in Turkey, the casa baraccata technique in Italy, the pontelarisma technique in Greece and the Pombalina structures in Portugal. Pombalina structures, originate from after the Lisbon Earthquake in 1755. Notable features of such structures include reinforcement by the gaiola, an internal wooden cage.

Figure 8 from left to right: The göz dolmas and muskali dolmas technique in Turkey, the gaiola in Lisbon, and the pontelarisma technique in Lefkada (Greece).

As Kevin Lynch, a well-known 19th century urban planner and author of the famous “The image of the city”, used to say, cities are not only physical places, but embed symbolic and cultural meanings that are “inscribed” in the way they have been designed and in the way places and spaces have been designed and built.

That is to say: cities are more than just physical spaces. We humans find meaning in their structure and how, in turn, those structures shape our lives. The meaning we give to the intertwining of the physical and the social in those spaces changes how we see disasters. The richer a city in terms of cultural meaning, the larger its potential for people living and visiting it to develop a geography of the place, made of points of reference and milestones representing guiding elements within the built environment.

Chapter 1.4: Cultural heritage and disaster in today’s cities