Earthslips:

Unpredictable and unforeseen

Earthslips aka landslides are rock, earth or debris flows. However bad the term many sound earthslips are an integral part of earth's surface geology. Earthslips can be either abrupt or gradual, serve to redistribute soil and sediments.

Although gravity is the primary driving force, many other factors contribute for the stability of slopes to be compromised. They are often require a trigger before being released.

They are often caused by changes in groundwater pressure, which can destabilize a slope, absence of trees, erosion of the slope, weakening of the slope through soaking from heavy rains and earthquakes. Landslides are aggravated by human activities.

Such instigating factors include deforestation, unplanned cultivation and construction, removal of deep-rooted vegetation that binds top soil to bedrock and logging. Add to all that vibrations from machinery and traffic and earthslips can be virtually unpreventable as well as unforeseen.

In the past few days floods and landslides have affected more than a million people and have forced 339,200 from their homes. Three days of rain has damaged over 80,000 hectares of agricultural land. So far, 32 people have died. Although earthslips mainly affect in the eastern, central and north central parts of Sri Lanka, any other part of the country with unstable slopes are also in danger.

Areas prone to earthslips

On or at the base or top of slopes
At the base or top of a steep cut slope Warning signs
Springs, seeps or saturated ground in areas that have not typically been wet before
New cracks or unusual bulges in the ground, street pavements or sidewalks
New cracks appear in walls, tile, brick or foundations
Soil moving away from foundations
Tilting or cracking of concrete floors and foundations
Broken water lines and other underground utilities
Telephone poles, fences, retaining walls, utility poles, or trees tilt or move
Sunken roads
Sudden decrease in surface water levels in spite of rain
Doors or windows jam for the first time
Outside walls, pavements or stairs begin pulling away from the building
Slowly developing, widening cracks on the ground or on paved areas such as streets
Water breaks through the ground surface in new locations
A faint rumble that increases in volume
The ground slopes downward in one specific direction and may begin shifting in that direction underfoot

What to do
During an earthslip, if inside a building take cover under a desk, table or other piece of sturdy furniture.
If outdoors try to get out of the path of the landslide, run to the nearest high ground in a direction away from the path. If rocks and other debris are approaching, run for the nearest shelter such as a group of trees or a building. If escape is not possible, curl into a tight ball and protect your head. After an earthslip stay away from the area. There may be danger of more slides. Remember that flooding may occur after a landslide.

- Sajitha