Landslides can be caused by earthquakes or volcanoes, but in Queensland, they’re generally caused by heavy rain. The rain saturates the soil on a hillside—often where there has been human activity (e.g. construction where trees and plants have been removed)—past the point where any remaining vegetation can support the soil’s weight against the force of gravity. The top saturated layer of soil then slips down the hill—taking whatever is on the land with it.
Landslides may be exceptionally slow—moving only centimetres a year—or fast, with a sudden and total collapse, moving millions of tonnes of debris.
The distance a landslide travels also varies greatly—from a few centimetres in 'ground slumps', to many kilometres when large mud flows follow river valleys.
Preparing for landslides
You can protect yourself, your family and your property by doing the following:
- Before occupying a building, check with the local council and neighbours for the area's history of landslides or instability.
- In steep areas, look for the tell-tale signs of ground movement, such as trees tilting (down-slope), water seepage and breaks in the ground.
- If outdoors always heed warning signs, and avoid the tops and bases of cliffs and embankments, especially where there are signs of loose rocks or debris. Never stand or sit on rock overhangs unless you are sure they can bear your weight.
During a landslide
- If indoors—shelter at the least-affected end of the building under a strong table or bench (if possible, use a mattress for extra protection). Hold on firmly and stay put until all land movement has stopped.
- If outdoors and a landslide threatens, move quickly from its path and keep clear of banks, trees, powerlines and poles.