Lima

The evaluation of city scenarios in Lima is considered relevant as a contribution for the understanding of potential earthquake losses in a city with a large number of inhabitants in which the concentration of exposed values is relevant at the country level.

The population estimated for 2015 is 9,168,542.00 inhabitants . The city is divided into 49 districts (see Figure below). The total area is around 2811 km2 , leading to an urban population density of 3262 inhabitants per km2.The percentage of population living under poverty conditions is around 14.5% ; the contribution of the city to the Gross Domestic Product is considered near to 53% (Alonso et al 2007), given the concentration of the financial system and the production of the majority of national manufacturing production and services in Lima (Riofrio 2003).

Regarding the housing conditions, two main problems have been identified: a significant part of the population lives in deteriorated and dense occupied structures. It corresponds to tenements in the historical areas of the city; tenements in areas not considered historical or monumental and modern buildings with severe overcrowding. Other significant part of the low income population lives in informal areas, without urban planning restrictions, low building requirements and a poor coverage of social and public services. It is considered that this type of settlement has concentrated the city's population growth since the 1960s and probably house a 35% of the population today (Riofrio 2003).

Both areas represent a considerable proportion of population living in buildings that could be heavily affected during earthquakes. Therefore, it is necessary to measure the population exposed to this areas, the fragility of the buildings they occupy and the potential effects of likely seismic events

Quito

The evaluation of city scenarios in Quito is a matter of interest of the local government and institutions responsible of seismic risk management. The event ocurred in August 2014 highlighted the need of updating loss estimations, taking into account the socioeconomic vulnerability of the population. Therefore, this case study is considered as a good example that could be repeated in other cities of South America.

According to the Census of 2010, the population was estimated as 2,239,191 inhabitants. In Table 1.1 the vulnerable groups as percentage of the total population are presented. From this table it is possible to observe that the percentage of the working age population (between 18 and 65 years) is relatively high (around 58.9%) and the unemployment rate is low (near 3.6%). Nevertheless, more than a third of the population (36.4%) is below the poverty line (SHTV, 2013)

The Metropolitan District of Quito (MDQ) is divided into Administrative units and neighborhood sectors (see Figure 1.2). The total area is 423,050 ha and the urban area corresponds to 52,479 ha, leading to an urban population density of 42.7 inhabitants per ha. Between 1990 and 2001, the annual population growth rate was 2.6%; between 2001 and 2010 this rate was 2.2% (SHTV, 2013). The estimated contribution of the city to the Gross National Production (GNP) is around 15% (La Hora, 2011).

Inputs for the exposure model of Quito

In a close communication with the system of risk management of the city, it has been agreed to build a exposure model of the city by using the following sources of information: Recent cadastral databases Results of the survey of buildings conducted during the study of the Metro line, which includes: (i) technical forms for the description of each one of the buildings surveyed (around 400 buildings); (ii) maps with the localization, building identification and structural classifications and (iii) architechtural and structural plans of a sample of buildings.

Intermediate cities of Chile: Iquique, Rancagua and Osorno

Within the scope of the collaboration agreement with researchers from CIGIDEN, a detailed exposure model for Iquique (located at the north of Chile with 180601 inhabitants), Osorno (located at southern Chile with 145475 inhabitants) and Rancagua (located in the central region with 232,524 inhabitants) is being developed. These cities have been selected due to their location, population and exposure to earthquake events.

Moreover, the consequences of the earthquake of Iquique (1st April of 2014) highlighted the relevance in improving the understanding of the damage potential of earthquakes in these areas (see Figure 7). The partners of CIGIDEN participated in the evaluation of damages and the GEM IDCT tools were employed in the classification of the damaged buildings.

City scenarios in Colombia

Medellín

With the collaboration of the research group of EAFIT, a detailed exposure model by neighborhoods (around 350) has been developed, which will include the number of buildings, built-up area, building typologies, and reposition and commercial values (see Figure below).

On the other hand, vulnerability functions of masonry structures have been derived by using With the information above, the vulnerability functions that are currently being derived for residential buildings in Antioquia (Colombia), the regional seismic hazard model described in Work package 1, it will be possible to calculate earthquake losses for specific scenarios using the OpenQuake-engine. More details regarding the exposure model of Medellín are presented in Annex B

  • city_scenarios.txt
  • Last modified: 2015/05/13 12:27
  • by Jairo Valcarcel