Landslide case study: Vaiont Dam 1963
This is the video used in class.
and here is the short “fly by” video of the animated sequence
Flow Case Study: Aberfan 1966
The coal tip disaster of 1966 in a Welsh mining town of Aberfan is referred to on page 76 of your book. Also look at the model of a slope failure case study from page 77 (Dunedin). There is a good video to introduce the case of Aberfan:
1. What happened? This should describe the event simply saying what movement took place and what were the consequences.
2. Analysis of the event from a geography point of view should show the processes that led the the disaster.
3. Who was responsible for the disaster and what should/could have been done to manage the potential danger ?
All these key facts should be in your study, with description and analysis in detail:
· Spoil heaps located above porous sandstone containing underground springs – concerns had been raised about the stability due to these springs. (National Coal Board ignored these).
· Heavy rain in the days preceding the disaster caused an increase in the water table, water acted as a lubricant to allow subsidence of the spoil heaps.
· Spring had also undercut the heaps, and removed clay destabilising the toe decreasing stability.
· 09:15 am tip 7 collapses sending 100’000 cubic meters of colliery waste down the hillside.
· The landslide gathered speeds of up to 30km/hr.
· Pantglas Junior School was crushed by the landslide – 147 people killed including a whole generation of children who were in assembly at the time.
Summary of contributing factors:
· Human neglect- coal board did not listen to the worries of the miners and locals, continuing to dump on tip 7 despite earlier signs of instability
· Location of springs under spoil heaps – lubricant and undercutting
· Time of day – children all gathered in school
· Heavy rainfall raising water table
British Geological Survey has a wide range of material on slope processes
In concluding your Aberfan case study make sure to refer to the changes in legislation about coal tipping, following the Aberfan disaster. http://www.bgs.ac.uk/mineralsUK/planning/legislation/minewaste.html
BGS landslide case studies are worth exploring.