1. What are the different geological hazards that are triggered by rain?
   - Rainfall is a primary cause of geological disasters such as landslides, debris flows, and floods.

2. Explain the causes of rainfall-induced geological hazards: landslides and sinkholes.

   - Landslides are caused by disturbances in the natural stability of a slope.

   - Minerals in the rock were dissolved by water, leaving behind residue and voids. (Weathering is the term for this.)

   - The soil and debris in the rock voids are removed by water.

   - Falling groundwater levels can result in the soft material in the rock voids losing support, which might trigger collapse.

   - The surface may collapse as a result of the groundwater gradients changing as a result of adding or removing water from the system or loose material flushing out of the voids more quickly.

   - Every alteration to the hydrologic system, such as adding more water or removing it, makes the system at least momentarily unstable and increases the risk of sinkholes.

3. Identify the signs of impending landslides and sinkholes.

   - Fences, retaining walls, utility poles, or trees tilt or move. A faint rumbling sound that increases in volume is noticeable as the landslide nears. Unusual sounds, such as trees cracking or boulders knocking together, might indicate moving debris. Cracks around door and window frames. An increasing number of exposed tree roots on your property. Cracks in your foundation, walls, or swimming pool. Sagging fence posts, utility poles or trees, or loosening of the soil around them. Sloping floors. Problems closing doors or windows. etc.

4. Give and identify available or existing instruments used to predict or validate the possible occurrence of landslides or sinkholes.

   - Satellite radar images have long been used to predict and capture the early warning signs of impending natural disasters, including landslides – tonnes of rock, earth, mud or debris moving down a slope, often destroying everything in their paths.

   - To be able to predict landslides, scientists have developed slope stability models to analyze the risk locally. More recently, NASA has created a preliminary algorithm to map landslide hazards globally using satellite measurements of rainfall, land cover and other surface variables.

5. Explain and give an example of geohazard maps of landslides.

   - Landslide hazard maps indicate the possibility of landslides occurring throughout a given area. An ideal landslide hazard map shows not only the chances that a landslide might form at a particular place, but also the chance that it might travel downslope a given distance.

6. Give the safety precautionary measures in case of landslide and sinkhole.​

   - Stay away from and do not let children play near cliff edges and steep slopes, especially after heavy rains. Call your local police or public works if you see a slide or sinkhole. Do not enter caves or sinkholes that may collapse further or be filled with deadly poisonous natural gases.