Triggering conditions and depositional characteristics of a disastrous debris flow event in Zhouqu city, Gansu Province, northwestern China
On 7 August 2010, catastrophic debris flows were triggered by a rainstorm in the catchments of the Sanyanyu and Luojiayu torrents, Zhouqu County, Gansu Province northwestern China. These two debris flows originated shortly after a rainstorm with an intensity of 77.3 mm h<sup>−1<...
Main Authors: | , , , , |
---|---|
Format: | Article |
Language: | English |
Published: |
Copernicus Publications
2011-11-01
|
Series: | Natural Hazards and Earth System Sciences |
Online Access: | http://www.nat-hazards-earth-syst-sci.net/11/2903/2011/nhess-11-2903-2011.pdf |
id |
doaj-1e6ffda9ca5d414697ce69e043ef7715 |
---|---|
record_format |
Article |
spelling |
doaj-1e6ffda9ca5d414697ce69e043ef77152020-11-24T23:32:45ZengCopernicus PublicationsNatural Hazards and Earth System Sciences1561-86331684-99812011-11-0111112903291210.5194/nhess-11-2903-2011Triggering conditions and depositional characteristics of a disastrous debris flow event in Zhouqu city, Gansu Province, northwestern ChinaC. TangN. RengersTh. W. J. van AschY. H. YangG. F. WangOn 7 August 2010, catastrophic debris flows were triggered by a rainstorm in the catchments of the Sanyanyu and Luojiayu torrents, Zhouqu County, Gansu Province northwestern China. These two debris flows originated shortly after a rainstorm with an intensity of 77.3 mm h<sup>−1</sup> and transported a total volume of about 2.2 million m<sup>3</sup>, which was deposited on an existing debris fan and into a river. This catastrophic event killed 1765 people living on this densely urbanised fan. The poorly sorted sediment contains boulders up to 3–4 m in diameter. In this study, the geomorphological features of both debris flow catchment areas are analyzed based on the interpretation of high-resolution remote sensing imagery combined with field investigation. The characteristics of the triggering rainfall and the initiation of the debris flow occurrence are discussed. Using empirical equations, the peak velocities and discharges of the debris flows were estimated to be around 9.7 m s<sup>−1</sup> and 1358 m<sup>3</sup> s<sup>−1</sup> for the Sanyanyu torrent and 11 m s<sup>−1</sup> and 572 m<sup>3</sup> s<sup>−1</sup> for the Luojiayu torrent. The results of this study contribute to a better understanding of the conditions leading to catastrophic debris flow events.http://www.nat-hazards-earth-syst-sci.net/11/2903/2011/nhess-11-2903-2011.pdf |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
C. Tang N. Rengers Th. W. J. van Asch Y. H. Yang G. F. Wang |
spellingShingle |
C. Tang N. Rengers Th. W. J. van Asch Y. H. Yang G. F. Wang Triggering conditions and depositional characteristics of a disastrous debris flow event in Zhouqu city, Gansu Province, northwestern China Natural Hazards and Earth System Sciences |
author_facet |
C. Tang N. Rengers Th. W. J. van Asch Y. H. Yang G. F. Wang |
author_sort |
C. Tang |
title |
Triggering conditions and depositional characteristics of a disastrous debris flow event in Zhouqu city, Gansu Province, northwestern China |
title_short |
Triggering conditions and depositional characteristics of a disastrous debris flow event in Zhouqu city, Gansu Province, northwestern China |
title_full |
Triggering conditions and depositional characteristics of a disastrous debris flow event in Zhouqu city, Gansu Province, northwestern China |
title_fullStr |
Triggering conditions and depositional characteristics of a disastrous debris flow event in Zhouqu city, Gansu Province, northwestern China |
title_full_unstemmed |
Triggering conditions and depositional characteristics of a disastrous debris flow event in Zhouqu city, Gansu Province, northwestern China |
title_sort |
triggering conditions and depositional characteristics of a disastrous debris flow event in zhouqu city, gansu province, northwestern china |
publisher |
Copernicus Publications |
series |
Natural Hazards and Earth System Sciences |
issn |
1561-8633 1684-9981 |
publishDate |
2011-11-01 |
description |
On 7 August 2010, catastrophic debris flows were triggered by a rainstorm in the catchments of the Sanyanyu and Luojiayu torrents, Zhouqu County, Gansu Province northwestern China. These two debris flows originated shortly after a rainstorm with an intensity of 77.3 mm h<sup>−1</sup> and transported a total volume of about 2.2 million m<sup>3</sup>, which was deposited on an existing debris fan and into a river. This catastrophic event killed 1765 people living on this densely urbanised fan. The poorly sorted sediment contains boulders up to 3–4 m in diameter. In this study, the geomorphological features of both debris flow catchment areas are analyzed based on the interpretation of high-resolution remote sensing imagery combined with field investigation. The characteristics of the triggering rainfall and the initiation of the debris flow occurrence are discussed. Using empirical equations, the peak velocities and discharges of the debris flows were estimated to be around 9.7 m s<sup>−1</sup> and 1358 m<sup>3</sup> s<sup>−1</sup> for the Sanyanyu torrent and 11 m s<sup>−1</sup> and 572 m<sup>3</sup> s<sup>−1</sup> for the Luojiayu torrent. The results of this study contribute to a better understanding of the conditions leading to catastrophic debris flow events. |
url |
http://www.nat-hazards-earth-syst-sci.net/11/2903/2011/nhess-11-2903-2011.pdf |
work_keys_str_mv |
AT ctang triggeringconditionsanddepositionalcharacteristicsofadisastrousdebrisfloweventinzhouqucitygansuprovincenorthwesternchina AT nrengers triggeringconditionsanddepositionalcharacteristicsofadisastrousdebrisfloweventinzhouqucitygansuprovincenorthwesternchina AT thwjvanasch triggeringconditionsanddepositionalcharacteristicsofadisastrousdebrisfloweventinzhouqucitygansuprovincenorthwesternchina AT yhyang triggeringconditionsanddepositionalcharacteristicsofadisastrousdebrisfloweventinzhouqucitygansuprovincenorthwesternchina AT gfwang triggeringconditionsanddepositionalcharacteristicsofadisastrousdebrisfloweventinzhouqucitygansuprovincenorthwesternchina |
_version_ |
1725533399771250688 |