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Landslide

January 19, 2011, by Ken Jorgustin

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landslide-in-laguna-beach-california-2005

On average, landslides kill about 8,000 people every year. They can occur without warning.

Landslides are becoming more frequent as the sprawl of population takes us further into other terrain where hills and slopes are altered to accommodate us.

For example, during the winter months in California, if there are excessive rains, landslides become a common report on the nightly news due to the hilly and often steep terrain in many parts of the state where large amounts of the population live.


Landslides will happen anywhere, so long as the ingredients are in place.

First, the slope itself needs to be predisposed to slide. That is, the soil make-up and composition (type of soil, rock, layers) and the slope angle.

Next, the slope needs a trigger to start the landslide. The most common trigger (90 percent of instances) is excessive rainfall, be it short lived but very heavy, or a longer period with lots of rain.

An example, and an event currently in the news, the recent record breaking amount of rain in Brazil has caused devastating landslides that have tragically killed 700 people so far.

The next likely trigger is from an earthquake. The obvious shaking during an earthquake will send waves through the earth (which quite often can literally be observed) and can upset the forces holding a slope together. Depending on the soil, a phenomenon called ‘liquefaction’ can occur, changing the ground from solid to something closer to quicksand.


The most scary thing about landslides is after having seen a few (videos below), one realizes the grave danger of being caught in one. You would literally probably get swallowed up almost immediately, with hardly a chance to survive.

Knowing that they often occur with no warning (some can be predicted), living on a steep hill with the nice view suddenly doesn’t seem like such a good idea.

What kind of preparations could someone do if they know they live in an area that could be prone to slide? Well, if the house goes, so does everything in it, including you. All one could do really, is to just be aware of the danger. Awareness is always the most important step in many situations. While ignorance may be bliss, awareness may save your life.


Here are a few hand-picked videos that may open your eyes to the power of sliding earth.

Landslide – National Geographic, Portland-Oregon and others
[youtube]http://www.youtube.com/watch?v=mknStAMia0Q[/youtube]


Landslide – Japan
[youtube]http://www.youtube.com/watch?v=F31ywRvtNkY[/youtube]


Landslide – Southern Italy
[youtube]http://www.youtube.com/watch?v=R__3DYQCVnA[/youtube]


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