Landslides, the hazards are real

With more than a billion dollars of damages every year, the landslide problem is quickly being addressed by both the government and the scientific community. In order for the continuous expansion of the urban and recreational landscapes, government agencies and land developers are looking for the assistance of scientists to better understand the nature of landslides and how to avoid them.

What is a landslide?

Generally, any down slope movement of a mass of soil, rock, or other debris is considered a landslide. This broad definition covers more specific kinds of down slope movements like mudflows or mudslides. As we all know, anything that might cause the loosening of the soil can cause landslides. Natural causes include rains, earthquakes, volcanic activities, and even changes in groundwater. Magnitude 4.0 and greater earthquakes are known to trigger landslides.

On the other hand, any human disturbance and change on a slope can cause a landslide. Such human actions include man-made construction activities, and inducing unnecessary ground stress like development of a housing community on a slope. Also included in the list of landslide causes include river erosions, glaciers, and because of the extra weight from accumulated snow, stockpiling of rock or ore.

Landslides are not exclusive on land. There are underwater movements of debris which are called submarine landslides. The landslides that occur underwater can cause tsunamis.

As of the moment, the record holder for the world's biggest landslide is the one that occurred during the 1980 eruption of Mount St. Helens, in the Cascade Mountain Range in the State of Washington, US. The volume of material displaced and brought down slope was said to be 2.8 km³.

Causes of landslides

Natural causes:

• groundwater pressure acting to destabilize the slope
• Loss or absence of vertical vegetative structure, soil nutrients, and soil structure.
• erosion of the toe of a slope by rivers or ocean waves
• weakening of a slope through saturation by snowmelt, glaciers melting, or heavy rains
• earthquakes adding loads to barely-stable slopes
• earthquake-caused liquefaction destabilizing slopes
• volcanic eruptions

Human causes:

• vibrations from machinery or traffic
• blasting
• earthwork which alters the shape of a slope, or which imposes new loads on an existing slope
• in shallow soils, the removal of deep-rooted vegetation that binds colluvium to bedrock
• Construction, agricultural, or forestry activities which change the amount of water which infiltrates into the soil.

Signs indicators to predict landslide

Geological studies have given people some important precautionary indicators to which would help determine if a major landslide is imminent. Look at the ground area, if you notice the presence of cracks and unusual bulges on the soil then there might be an impending major landslide or slope movement.

The same thing could happen if the soil suddenly began to move away from the foundations. Other signs of possible landslide scenario include broker water pipes, leaning telephone poles or trees, unlined fences, leaning walls, sunken road beds, and sudden decrease of creek water levels.

Areas that are generally prone to landslide

To be on the safe side, if would be wise to avoid areas that are naturally prone to landslides. If you plan on going outdoors and encounter a sudden natural calamity like an earthquake for example, you should avoid areas that have had landslides before or areas like the base of slopes, base of minor drainage hollows, as well the bases or tops of old fill slopes and steep cut slopes. Developed hillsides are also prone to landslides so we recommend avoiding those kinds of areas as well.

Not only do landslides cause major destructions of properties in the US, but also this geological hazard is known to cause more than 25 fatalities every year. Consider the country lucky. Other areas across the globe experience more human losses attributed to landslides, Fatalities of this nature, can be avoided through proper research, understanding, and dissemination of information about landslides.