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Titel |
Risk assessment of debris flow in Yushu seismic area in China: a perspective for the reconstruction |
VerfasserIn |
H. X. Lan, L. P. Li, Y. S. Zhang, X. Gao, H. J. Liu |
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. 11 ; Nr. 13, no. 11 (2013-11-22), S.2957-2968 |
Datensatznummer |
250085563
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Publikation (Nr.) |
copernicus.org/nhess-13-2957-2013.pdf |
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Zusammenfassung |
The 14 April 2010 Ms = 7.1 Yushu Earthquake (YE) had caused
severe damage in the Jiegu township, the residential centre of Yushu Tibetan
Autonomous Prefecture, Qinghai Province, China. In view of the fragile
geological conditions after YE, risk assessment of secondary geohazards
becomes an important concern for the reconstruction. A quantitative
methodology was developed to assess the risk of debris flow by taking into
account important intensity information. Debris flow scenarios were
simulated with respect to rainfall events with 10, 50 and 100 yr
returning period, respectively. The possible economic loss and fatalities
caused by damage to buildings were assessed both in the settlement area and
in the low hazard settlement area regarding the simulated debris flow
events. Three modelled building types were adopted, i.e. hollow brick wood
(HBW), hollow brick concrete (HBC) and reinforced concrete (RC) buildings.
The results suggest that HBC structure achieves a good balance for the
cost-benefit relationship compared with HBW and RC structures and thus could
be an optimal choice for most of the new residential buildings in the Jiegu
township. The low hazard boundary presents significant risk reduction
efficiency in the 100 yr returning debris flow event. In addition, the
societal risk for the settlement area is unacceptable when the 100 yr
returning event occurs but reduces to ALARP (as low as reasonably
practicable) level as the low hazard area is considered. Therefore, the low
hazard area was highly recommended to be taken into account in the
reconstruction. Yet, the societal risk might indeed approach an unacceptable
level if one considers that YE has inevitably increased the occurrence frequency of
debris flow. The quantitative results should be treated as a perspective for
the reconstruction rather than precise numbers of future losses, owing to the
complexity of the problem and the deficiency of data. |
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