Thursday, February 12, 2009

What Causes Landslides In Southeast Asia

Landslides can be caused by a number of factors, including deforestation and increased rainfall.


Landslides can wipe out entire villages and mountainsides in many parts of Asia. Although many landslides have natural causes, these natural causes may be made worse by building patterns and deforestation. Landslides can kill hundreds of people and damage crop production.


Deforestation


Deforestation can reduce a hill or mountainside's ability to remain in place. Plant roots help prevent saturated soils from sliding down a steep slope. Deforestation can be a contributing factor to some landslides in Southeast Asia


Typhoons


Typhoons and other tropical cyclones bring very heavy rainfall in very short periods of time. In some cases, soil on the sides of hills and mountains can quickly become over-saturated and begin to slide downhill.


Torrential Rains


Southeast Asia is tropical and sub-tropical. There are distinct rainy and dry seasons. During a particularly wet rainy season, the land can become over-saturated in much the same way that it can during a typhoon.


Earthquake


Earthquakes, especially earthquakes when the land is over-saturated from either a typhoon or torrential rains, can trigger a landslide by shaking already loose soil down a hill or mountainside.


High Tides and Tsunamis








Unusually high tides can sometimes weaken the base of a hillside that may already be weak from over-saturation or deforestation. Tsunamis, or tidal waves, can also move quickly inland, weakening the base of hills and mountainsides. These weaker bases can play a part in a landslide.


Flooding


Flooding can, much like very high tides and tsunamis, weaken the base of hills and mountainsides and help contribute to landslides. In some cases, deforestation can lead to increased runoff into rivers and increases in flooding.

Tags: Southeast Asia, base hills, base hills mountainsides, become over-saturated, high tides, hill mountainside, hills mountainsides