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| Titel |
Combining criteria for delineating lahar- and flash-flood-prone hazard and risk zones for the city of Arequipa, Peru |
| VerfasserIn |
J.-C. Thouret, G. Enjolras, K. Martelli, O. Santoni, J. A. Luque, M. Nagata, A. Arguedas, L. Macedo |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1561-8633
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| Digitales Dokument |
URL |
| Erschienen |
In: Natural Hazards and Earth System Science ; 13, no. 2 ; Nr. 13, no. 2 (2013-02-14), S.339-360 |
| Datensatznummer |
250017572
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| Publikation (Nr.) |
 copernicus.org/nhess-13-339-2013.pdf |
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| Zusammenfassung |
Arequipa, the second largest city in Peru, is exposed to many natural
hazards, most notably earthquakes, volcanic eruptions, landslides, lahars
(volcanic debris flows), and flash floods. Of these, lahars and flash
floods, triggered by occasional torrential rainfall, pose the most
frequently occurring hazards that can affect the city and its environs, in
particular the areas containing low-income neighbourhoods. This paper
presents and discusses criteria for delineating areas prone to flash flood
and lahar hazards, which are localized along the usually dry (except for the
rainy season) ravines and channels of the Río Chili and its tributaries that
dissect the city. Our risk-evaluation study is based mostly on field surveys
and mapping, but we also took into account quality and structural integrity
of buildings, available socio-economic data, and information gained from
interviews with risk-managers officials.
In our evaluation of the vulnerability of various parts of the city, in addition
to geological and physical parameters, we also took into account selected
socio-economic parameters, such as the educational and poverty level of the
population, unemployment figures, and population density. In addition, we
utilized a criterion of the "isolation factor", based on distances to
access emergency resources (hospitals, shelters or safety areas, and water)
in each city block. By combining the hazard, vulnerability and exposure
criteria, we produced detailed risk-zone maps at the city-block scale,
covering the whole city of Arequipa and adjacent suburbs. Not surprisingly,
these maps show that the areas at high risk coincide with blocks or
districts with populations at low socio-economic levels. Inhabitants at
greatest risk are the poor recent immigrants from rural areas who live in
unauthorized settlements in the outskirts of the city in the upper parts of
the valleys. Such settlements are highly exposed to natural hazards and have
little access to vital resources.
Our study provides good rationale for the risk zoning of the city, which in
turn may be used as an educational tool for better understanding the
potential effects of natural hazards and the exposure of the population
residing in and around Arequipa. We hope that our work and the risk-zonation
maps will provide the impetus and basis for risk-management authorities of
the Municipality and the regional government of Arequipa to enforce existing
regulations in building in hazardous zones and to adopt an effective
long-term strategy to reduce risks from lahar, flash flood, and other
natural hazards. |
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