Access: Drive right to the end of Puncak Bukit Mutiara 2, Plenty of parking.
In Penang the term Landslide is heard quite frequently during the rainy season. Often landslides occur high up a mountain, close roads down for months at a time and are very difficult to go view. I have found one that you can drive right up to. You can stand on the road and look up and down to see the landslide and the damage that it has caused. It is quite interesting, with many lessons to be learned.
A little information about landslides:
Landslides occur when the slope changes from a stable to an unstable condition. A change in the stability of a slope can be caused by a number of factors, acting together or alone. Natural causes of landslides include:
- groundwater pressure acting to destabilize the slope
- loss or absence of vegitation (e.g. after a wildfire or a clear cutting of an area)
- erosion of a slope by rivers, oceans, streams
- weakening of a slope through saturation by snow melting, glaciers melting, or heavy rain
- earthquakes
Landslides are aggravated by human activities, such as:
- Deforestation, cultivation and construction
- Vibrations from machinery or traffic
- Explosions
- Earthworks engineering which alters the shape of a slope, or which imposes new loads on an existing slope
- The removal of deep-rooted vegetation that binds loose materials to bedrock
- Construction, agricultural or forestry activities (logging) which change the amount of water infiltrating the soil.
The action of gravity is the primary driving force for a landslide to occur, although there are other contributing factors affecting slope stability. Typically, pre-conditional factors build up specific surface or sub-surface conditions that make a slope prone to failure, whereas the actual landslide often requires a trigger before being released.
The causes of landslides are usually related to instabilities in slopes. It is usually possible to identify one or more landslide causes and one landslide trigger. The difference between these two concepts is subtle but important. The landslide causes are the reasons that a landslide occurred in that location and at that time.
Causes may be considered to be factors that made the slope vulnerable to failure, that predispose the slope to becoming unstable. The trigger is the single event that finally initiated the landslide. Thus, causes combine to make a slope vulnerable to failure, and the trigger finally initiates the movement. Landslides can have many causes but can only have one trigger. Usually, it is relatively easy to determine the trigger after the landslide has occurred (although it is often very difficult to determine the exact nature of landslide triggers ahead of a movement event). Occasionally, even after detailed investigations, no trigger can be determined.
In the majority of cases the main trigger of landslides is heavy or prolonged rainfall. Generally this takes the form of either an exceptional short lived event, such as the passage of a tropical cyclone or even the rainfall associated with a particularly intense thunderstorm or of a long duration rainfall event with lower intensity, such as the cumulative effect of monsoon rainfall in Southeast Asia.
Questions about this landslide: Please send owner answers via email:
- 1) Identify one or more landslide causes at this site
- 2) What do you think was the landslide trigger?
- 3) Name 2 or more things that are being done to prevent future landslides at this site.
- 4) Would you live in those houses just to the right or left of the landslide?!?!
NOTE: I hope you have enjoyed this Earth Cache and have learned something about landslides. There are many answers to the questions above. Do not wait for my confirmation, if you believe you have successfully completed all Earth Cache goals and have already sent answers as requested, please, feel free to log it as FOUND. I will verify your answers later and send you a reply. Thanks for learning about landslides.