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MUD SLIDES - Case Study of Aberfan

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What are Mudslides?

How do these occur................................??

A mudflow is a flow of water that contains large amounts of suspended particles and silt. They can travel up to speeds of  60 miles an hour across the earths surface and risks destroying mudflow everything on its journey. Boulders as large as houses have been moved by mudflows.
 
So how do they Occure ???

During prolonged periods of  rains, a mudslides are at  there most lethal  and can strike without warning. If the rains persist,  the ground can become exceedingly saturated, causing a hillside to literally move.  Such a move is called a shift.  A diagram of hill failure can be seen below;

Here we can see that the original material caaried by the mudflow has been prized away from the scar  down the slope forming a trough of debris moving downward.  As it moves further down the slope, it increases in speed, until it reaches the Fan/Mound of deposition.  It is here where the slide stops and deposits its load at the foot of the slope.

On its way it can collect  rocks, trees, houses and cars and carry them as part of its load. As the debris moves into rivers and streambeds, bridges can become blocked or even collapse, making a temporary dam that can flood neighboring areas.

 

Being situated a the foot of the slope can be exceedingly costly to life and possessions.  The power of such a slide will take with it everything in its path. 
 
The reason from mud slides can be analysed on two levels - anthropogenically enhanced (man is to blame) or naturalistically enhanced (mother earth is to blame).  So see more on this discussion check out the who is to blame page!

An example of downslope movement.
mudslidelarger.jpg
A mud slide in Nicuraguia - : www.mercyteamnica.org/ mission.htm

Slop Movement in reality

Lucky Escape:

Fortunately, this slide only effected disused agricultural land, and spared the lives of villagers in surrounding homesteads.  Sadly, not all flows are so sparing! 

Areas at risk include-

Land Fill sites located in highly topographical locations.

Areas of over use in terms of resource extraction and mismanagement.

Areas over used for recreation.

Slopes with hazardous underlying strucutre and surface material.