The Vulnerability in Andean Cities: The Case of Quito and La Paz *Associate professor and researcher – Department of Geography - Geographical Research Institute – IIGEO - San Andres State University – La Paz, Bolivia alfredo.nunez@edu.uah.es *PhD Student – Department of Geography – University of Alcalá – Alcala de Henares, Spain janunez@umsa.bo
NUÑEZ-VILLALBA, Javier*
Urban Growth
INTRODUCTION Latin America is a unique place in terms of the phenomena affecting the world such as global change, migrations, and new democracies, since these phenomena are more drastic in this region. In terms of population for example, according to the United Nations Population Fund, the worldwide population will increase to 5 billion people, with the most significant growth in developing regions such as Latin America (where eighty percent of the planet's urban population is concentrated). Because the high concentration of population in urban areas, according to Pelling (2003), is only 1 % of the terrestrial surface, cities such as those in the Andean region become key places for the analysis of global change. Difficult geographic conditions (accessibility, climate, topography, etc.) in the Andean region have not impeded the construction of immense urban cities such as Quito and La Paz, which are both characterized by accelerated growth that is expanding through valleys and mountains. This growth multiplies both human and natural threats, however due to constant landslides in places with highest slopes (that cause entire neighborhoods to disappear) it is often believed that the most significant threats are natural, without taking into consideration the urban planning that allowed for these areas to be occupied in the first place. An analysis of the plannification of these urban areas, through a sequence of aerial photographs and satellite images shows the true vulnerability of these urban areas.
METHODOLOGY The methodology consisted of two elements: time and scale. Time Before, to get the images of the Earth's surface was necessary a photogrammetric flight. The high cost of a flight made it impossible to get images the surface more frequently. For example, every month.. It is now possible to get aerial photographs from space every month (GeoEye, WorldView2, etc..). This will apply a new methodology in observing the dynamics of accelerated growth of cities in South America.
aerial photograph
aerial photograph
aerial photograph
Midtow La Paz - Bolivia 1938
Midtow La Paz - Bolivia 1956
Midtow La Paz - Bolivia 1998
Scale The scale on satellite imagery is another factor that enables innovation in methodology to understand the vulnerability in urban areas. More than a decade ago it was impossible to do urban studies with satellite images of high resolution.
It is amazing to see the growth rate of the urban agglomeration of La Paz. In 20 years the new city of El Alto is twice the area of the city of La Paz. The High was born as a peripheral area of the city of La Paz on the 70's.
ANALYSIS AND RESULTS
The mountain chain of the Andes shape Andean cities. Also, set its growth in areas of steep slopes along the main river basin. Thus, cities are configured in a linear fashion, in the case of La Paz and Quito. image anaglyph from stereo pair of satellite images WorldView2 (11/04/2011 and 11/04/2011). Landslide of Callapa, City of La Paz, Bolivia
Callapa, La Paz City Image GeoEye1 2009/06/09
Now there is a bid of high resolution of 0.5 meters for pixel. Thus we can see small details of the areas destroyed in urban areas. Satellite Image LandSat ETM 7+ (30x30 meters for pixel) Airport. El Alto City - Bolivia.
Callapa, La Paz City Image WorldView2 2011/08/06
Satellite Image WorldView2 (0,5x0,5 meters for pixel) Airport. El Alto City - Bolivia
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References: Acknowledgments Pelling, 2003. “The Vulnerability of cities: natural disasters and Social Resilience”. Earthscan Ed., London. 256 p. D’ERCOLE R., HARDY S., METZGER P., ROBERT J., (2009). Vulnerabilidades urbanas en los países andinos. In: Bulletin de l’Institut Francais d’Études Andines /2009, 38 (3): p. 401-410. D’ERCOLE R., GLUSKI P., HARDY S., SIERRA A., (2009). Vulnérabilités urbaines dans les pays du Sud. Présentation du dossier. In: Cybergeo: European Journal ofGeography. URL: http://www.cybergeo.eu/index22151.html
Cantidad de desastres
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Both elements, time and scale, allow to find a new approach to understanding urban disasters. But beyond the disaster, we find that vulnerability is a major element in the Andean cities due to rapid growth of its cities. In the case of Quito and La Paz you can observe a high degree of growth.
The study showed that vulnerability is generated by the inhabitants themselves creating urban services such as access roads, health services, education, etc.. in hazardous areas. Sometimes we wonder why are there disasters? Using aerial photographs and satellite images in different times and scales can to argue more effectively the process of disaster, and the construction of vulnerability in Andean cities. A picture is worth a thousand words.
Callapa – La Paz, 2011. Fuente: Nunez, 2011
La Bota - Quito, 2010. Fuente: El Universo, 2010
Conclusions. Landslides in the Andean cities are frequent, and more on new areas of urban expansion. The most recent large magnitude occurred in the area of "La Bota" in the city of Quito in 2010, and "Callapa" in the city of La Paz in 2011. The images show all the aforementioned, the change of scenery is spectacular (before and after from disaster). The disaster is not the fault of the natural hazard, is fault from exposure of the houses in hazardous locations.