Article2,(Landslide)

http://en.wikipedia.org/wiki/Landslide

From the article that I have done read,I get new knowledge about that phenomena.the meaning of landslide is a geological phenomenon which includes a wide range of ground movement,such as rockfalls,deep failure of slopes and many more.Although the action of gravity is the primary driving force for a landslide to occur,there are other contributing factors affecting the original slope stability.On that article,the landslide occur when the stability of a slops 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.What can I understand landslide causes by groundwater  pressure acting to destabilize the slope,loss or absence of vertical vegetative structure, soil nutrients,and soil structure.Next earthquakes adding loads to barely stable slope.Landslide also causes by humans activities such as deforestation,cultivation,and contraction which destabilize the already fragile slopes.besides vibration from machinery or blasting.Landslides also can occur undersea,or have impact into water, can generate tsunamis.Massive landslides can also generate megatsunamis,which are usually hundreds of meters high.