Due to the loose Volcanic deposits that make up of the soil on Saint Vincent and on the Grenadines, landslides are the most common natural hazard with 2004, 2005 and 2010 recording numerous landslides .
Nevertheless, when natural disasters are mentioned, most people think about earthquakes, hurricanes or flooding rather than landslides. Even the historic records seem to indicate that landslides are less important than earthquakes, hurricanes or floods.
Most people tend to regard landslides as accidents, as something that only happens to others because, in comparison with earthquakes, hurricanes and floods, landslides affect relatively small and sharply delineated areas.
Landslides often move so slowly that even the people living in the affected area are not aware of it. They might only notice that from time to time, especially during or shortly after unusually wet periods, cracks develop in the walls of their dwelling. After a while they fix these cracks and forget about it.
The driving force behind all landslides is gravity. A landslide will occur when the gravitational pull increases when weight is added to the rock mass, for example, building on it or when the rock becomes saturated with water. The strength of a rock mass can be reduced by weathering, earthquakes, etc.
Landslides occur for a variety of reasons. They often occur as a result of natural phenomena but human activity can also be a factor:
- Vibrations from earthquakes can trigger a landslide.
- Water logging due to heavy rains can saturate the top layers of unstable soil and cause them to slide downhill.
- Human activity such as deforestation, vegetation removal, construction of roads, and construction of buildings on steep slopes may also lead to land slippage.
- Landslides may move very slowly from a few centimetres per year to a sudden, total collapse or avalanche.
- Landslides may travel just a few metres to many kilometres in the event of mudflows.
- Landslides can be deadly. They destroy houses, cars, water mains, gas pipes, anything in their path.
Landslides and mudflows can strike without warning, trapping or burying people.
Tell-Tale Signs of an Impending Landslide:
- Doors or windows stick or jam for the first time.
- New cracks appear in plaster, tile, brick, or foundations.
- Outside walls, walks, or stairs begin pulling away from the building.
- Slowly developing, widening cracks appear on the ground or on paved areas such as streets and driveways.
- Underground utility lines break.
- Bulging ground appears at the base of a slope.
- Ground water seeps to the surface in new locations.
- Fences, retaining walls, utility poles, or trees tilt or move.
You hear a faint, rumbling sound that increases in volume in one specific direction and may begin shifting in that direction under your feet.
How to tell of Your Property or Your Area is at Risk of Landslides:
Look at the slopes around you. If the land is soft and steep, if vegetation has been removed, if water collects near a slope, if the slope has been cut into “ all of these things could indicate danger. Also, if it has happened there before, it is likely to happen again.
Talk to old timers, persons who've lived in the area for some time, and ask the experts to find out more about the landslide history of the area. The more you know, the better prepared you area.
What You Can Do About It:
Take some of the following action to reduce your risk and loss. This is called mitigation:
- If you have not yet constructed, find out the history of the area and determine whether you really ought to construct there.
- If you go ahead with construction, plant trees and shrubs that bind the soil on slopes and build retaining walls. In mudflow areas, build channels or deflection walls to direct the flow around buildings.
- There may be legal issues if you divert mudflow to your neighbour's property.
- Plant or maintain well-rooted vegetation on slopes above and below your property. Don't remove any trees or vegetation unless the trees are diseased and pose a hazard.
- Refrain from doing so much paving that you channel storm run-off to an where it will collect and saturate the soil.
- Maintain good drainage.
- Beware of building on steep slopes or cutting into them to level the ground for building. It must be done properly and, in some places, not at all. Always consult an expert in this regard.
- Putting too much weight on vulnerable areas can contribute to landslide hazards. So can vibrations, such as those caused by jackhammers or heavy trucks.
- Beware of changing the natural course of water-ways. This can cause problems, if not to you, then to others.
The forces of nature are beyond our control but if we reduce our vulnerability landslides do not have to become disasters
Tell-Tale Signs of an Impending Landslide:
- Doors or windows stick or jam for the first time.
- New cracks appear in plaster, tile, brick, or foundations.
- Outside walls, walks, or stairs begin pulling away from the building.
- Slowly developing, widening cracks appear on the ground or on paved areas such as streets and driveways.
- Underground utility lines break.
- Bulging ground appears at the base of a slope.
- Ground water seeps to the surface in new locations.
- Fences, retaining walls, utility poles, or trees tilt or move.
- You hear a faint, rumbling sound that increases in volume in one specific direction and may begin shifting in that direction under your feet.
Source- CDEMA
- During a severe storm, stay alert and awake. Many deaths from landslides occur while people are sleeping.
- Listen to local news stations on a battery-powered radio for warnings of heavy rainfall.
- Listen for unusual sounds that might indicate moving debris, such as trees cracking or boulders knocking together.
- Move away from the path of a landslide or debris flow as quickly as possible. The danger from a mudflow increases near stream channels and with prolonged heavy rains. Mudflows can move faster than you can walk or run. Look upstream before crossing a bridge and do not cross the bridge if a mudflow is approaching.
- Avoid river valleys and low-lying areas.
- If you are near a stream or channel, be alert for any sudden increase or decrease in water flow and notice whether the water changes from clear to muddy. Such changes may mean there is debris flow activity upstream so be prepared to move quickly.
- Curl into a tight ball and protect your head if escape is not possible.
- Go to a designated public shelter if you have been told to evacuate or you feel it is unsafe to remain in your home. Find Nearest Shelter
- Stay away from the slide area. There may be danger of additional slides.
- Listen to local radio or television stations for the latest emergency information.
- Watch for flooding, which may occur after a landslide or debris flow. Floods sometimes follow landslides and debris flows because they may both be started by the same event.
- Check for injured and trapped persons near the slide, without entering the direct slide area. Direct rescuers to their locations.
- Look for and report broken utility lines and damaged roadways and railways to appropriate authorities. Reporting potential hazards will get the utilities turned off as quickly as possible, preventing further hazard and injury.
- Check the building foundation, chimney, and surrounding land for damage. Damage to foundations, chimneys, or surrounding land may help you assess the safety of the area.
- Replant damaged ground as soon as possible since erosion caused by loss of ground cover can lead to flash flooding and additional landslides in the near future.