Risk assessment of debris flow in Yushu seismic area in China: a perspective for the reconstruction

The 14 April 2010 <i>M</i><sub>s</sub> = 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...

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Main Authors: H. X. Lan, L. P. Li, Y. S. Zhang, X. Gao, H. J. Liu
Format: Article
Language:English
Published: Copernicus Publications 2013-11-01
Series:Natural Hazards and Earth System Sciences
Online Access:http://www.nat-hazards-earth-syst-sci.net/13/2957/2013/nhess-13-2957-2013.pdf
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spelling doaj-dd4c138963ac4dd093ea734f5ec7b2842020-11-24T21:13:45ZengCopernicus PublicationsNatural Hazards and Earth System Sciences1561-86331684-99812013-11-0113112957296810.5194/nhess-13-2957-2013Risk assessment of debris flow in Yushu seismic area in China: a perspective for the reconstructionH. X. Lan0L. P. Li1Y. S. Zhang2X. Gao3H. J. Liu4State Key Laboratory of Resources and Environmental Information System, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, ChinaState Key Laboratory of Resources and Environmental Information System, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, ChinaInstitute of Geomechanics, Chinese Academy of Geological Sciences, Beijing 100081, ChinaState Key Laboratory of Resources and Environmental Information System, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, ChinaState Key Laboratory of Resources and Environmental Information System, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, ChinaThe 14 April 2010 <i>M</i><sub>s</sub> = 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.http://www.nat-hazards-earth-syst-sci.net/13/2957/2013/nhess-13-2957-2013.pdf
collection DOAJ
language English
format Article
sources DOAJ
author H. X. Lan
L. P. Li
Y. S. Zhang
X. Gao
H. J. Liu
spellingShingle H. X. Lan
L. P. Li
Y. S. Zhang
X. Gao
H. J. Liu
Risk assessment of debris flow in Yushu seismic area in China: a perspective for the reconstruction
Natural Hazards and Earth System Sciences
author_facet H. X. Lan
L. P. Li
Y. S. Zhang
X. Gao
H. J. Liu
author_sort H. X. Lan
title Risk assessment of debris flow in Yushu seismic area in China: a perspective for the reconstruction
title_short Risk assessment of debris flow in Yushu seismic area in China: a perspective for the reconstruction
title_full Risk assessment of debris flow in Yushu seismic area in China: a perspective for the reconstruction
title_fullStr Risk assessment of debris flow in Yushu seismic area in China: a perspective for the reconstruction
title_full_unstemmed Risk assessment of debris flow in Yushu seismic area in China: a perspective for the reconstruction
title_sort risk assessment of debris flow in yushu seismic area in china: a perspective for the reconstruction
publisher Copernicus Publications
series Natural Hazards and Earth System Sciences
issn 1561-8633
1684-9981
publishDate 2013-11-01
description The 14 April 2010 <i>M</i><sub>s</sub> = 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.
url http://www.nat-hazards-earth-syst-sci.net/13/2957/2013/nhess-13-2957-2013.pdf
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