Zhouqu, China, disaster - data capture, modelling and preliminary geohazard assessment

Lead Research Organisation: University of Portsmouth
Department Name: Sch of Earth & Environmental Sciences

Abstract

At 1am on Sunday the 8th of August a large flow slide took place in Zhouqu, a county town in SW Gansu Province, China. Current information suggests that the trigger was a rainfall event delivering a reported 97mm in less than 40 minutes (annual precipitation averages from 400 to 900mm). Antecedent rainfall may also have played a role. The devastating event caused the deaths of more than 1000 people (1,144 as of Friday 13th of August in Zhouqu alone with at least 600 people still missing). In the wider region, mudslides and debris flows continue to affect the local population with further fatalities in Longnan (south and downstream of Zhouqu) and Tianshui (to the northeast). The region is characterised by a seismically active mountainous terrain, an extension zone of the Tibetan uplift, and was affected by the Wenchuan earthquake (12/5/2008) that generated and re-activated a large number of landslides. At Zhouqu, the local erosion base is formed by the Bailong River at about 1300m asl. The surrounding peaks reach heights of about 3500 to 3750m. The catchment where the sediments originate is approximately 20km2 and is characterised by very steep slopes. Vegetation cover is sparse with only a small remnant of upland forest cover remaining. Following the disaster a lively debate has sprung up apportioning blame to deforestation, hydropower development and mining in the area. In order to learn lessons from this kind of events, instead of speculation, a scientific approach is required to collect data, verify their robustness and make impartial observations and develop reliable process models that will be essential to develop appropriate mitigation strategies for the future. The site was visited in November 2009 by Dijkstra and Gibson and discussions were held with the government of Zhouqu about the risk posed by large landslides in the area. It is vitally important to collect data soon. As with all landslide events, an understanding of local geological structure, drainage, morphology and geotechnical parameters are essential in building a robust model of landsliding (e.g. Geertsma et al. 2006). The key characteristics of landslides and landslide dams in this region are often removed rapidly by the very instability that causes them. It is inherently difficult to map out the potential for landslides to transfer into catastrophic viscous flows with complex and transient mechanical and rheological interactions. However, this is an essential component in any reliable assessment of the risks. These sort of assessments are rare because of the scarcity of events available for this type of research. When these occur we must make the most of it. Mostly, our understanding of these processes is derived from small-scale laboratory experiments, requiring upscaling that may affect the relevance of the observations. In this case, a unique field laboratory is waiting to be explored to gain a better understanding of the risks posed by geohazards to the population in this region.

Publications

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Dijkstra T (2012) Geomorphic controls and debris flows - the 2010 Zhouqu disaster, China in Proceedings of the 11th International Symposium on Landslides

 
Description There is significant uncertainty regarding risks posed by channelised debris in the Bailong Corridor. VNIR techniques demonstrate considerable potential for reducing such uncertainties and improving knowledge of debris movement, debris origin and landscape evolution.
The nature and triggers for the Zhouqu debris flow disaster were identified, described and published.
Exploitation Route A great deal more work is required to improve models of how to better understand debris production and movement in mountainous regions. This work demonstrated that field investigation is necessary and that suitable remote sensing techniques can yield appropriate information.
Sectors Construction,Environment,Transport

 
Description Chengdu Workshop 
Organisation Natural Environment Research Council
Country United Kingdom 
Sector Public 
PI Contribution Travel to, participation and presentation at collaborative workshop
Collaborator Contribution NERC/ESRC funded travel
Impact None as yet
Start Year 2014
 
Description Lanzhou Arid Environment and Climate Change 
Organisation Lanzhou University
Country China 
Sector Academic/University 
PI Contribution Visiting Position and Informal Agreement on Future Collaboration
Start Year 2009
 
Description Lanzhou University 
Organisation Lanzhou University
Country China 
Sector Academic/University 
PI Contribution Agreement to spend at least 2 weeks in Lanzhou area of China per year 2015-17.
Collaborator Contribution Travel costs, accomodation costs and facilities costs will be borne by partner
Impact Promotion of committment and goodwill
Start Year 2014
 
Description Lanzhou University Institutional Collaboration 
Organisation Lanzhou University
Country China 
Sector Academic/University 
PI Contribution I hosted a visit and workshop between the Leadership Team of Lanzhou University to Leadership Team of University of Portsmouth.
Collaborator Contribution Travel to and attendance at workshop to discuss and promote institutional level memorandum of understanding
Impact Draft memorandum of understanding is currently in negotiation
Start Year 2014
 
Description NIR Spectroscopy of Chinese Debris Flows 
Organisation Lanzhou University
Country China 
Sector Academic/University 
PI Contribution XRD and VNIR spectral analyses of landslide debris
Collaborator Contribution Collection and supply of landslide debris from difficult to access debris flows China
Impact Peer-reviewed scientific paper is in production at present
Start Year 2014
 
Description NSFC 
Organisation National Natural Science Foundation of China
Country China 
Sector Public 
PI Contribution Attendance and presentation at workshop
Collaborator Contribution Accomodation, in-country travel and VISA sponsorship
Impact None yet
Start Year 2014
 
Description White Dragon III 
Organisation Transport Research Laboratory Ltd (TRL)
Country United Kingdom 
Sector Private 
PI Contribution Funding application to directed NERC CALL IRNH. My team led 2 work packages.
Collaborator Contribution TRL staff led a work package of the proposal.
Impact Application was shortlisted but unsuccessful
Start Year 2015
 
Description White Dragon Proposal 
Organisation British Geological Survey
Country United Kingdom 
Sector Public 
PI Contribution Grant submission to directed NERC call IRNH. My team led 2 of the workpackages.
Collaborator Contribution Bid IP was Dr Tom Dijkstra ,British Geological Survey who led bid development and editing.
Impact Grant Application was shortlisted, but not successful.
Start Year 2014
 
Description White Dragon Proposal II 
Organisation Loughborough University
Country United Kingdom 
Sector Academic/University 
PI Contribution Funding application to directed NERC CALL IRNH. My team led 2 work packages.
Collaborator Contribution LU staff led a collaborative work package
Impact Application was shortlisted but unsuccessful
Start Year 2015
 
Description What caused the 2010 Zhouqu Landslide Disaster? 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Open Research Seminar, promoted discussion of Chinese collaboration

I have started collaboration with Peter Brett Associates with respect to a potential karst database for central China
Year(s) Of Engagement Activity 2012
 
Description What caused the Zhouqu Debris Flow Disaster 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? Yes
Geographic Reach Regional
Primary Audience Professional Practitioners
Results and Impact Research seminar and public lecture, has promoted nkowledge of disasters in this region

I have been invited to join the Speakers for Schools Programme
Year(s) Of Engagement Activity 2011