Mass movements - landslides

Landslides

Rapid sliding of masses of earth, rock material, or regolith, moving 'en masse' without internal derangement of particles.

Causes of landslides

Factors include intense heavy rainfall, saturated soil becoming heavier and more vulnerable to gravity, and steep slopes close to failure.

Human Induced Activities

Activities like road construction, building on unstable slopes, deforestation, and quarrying contribute to landslides.

Thredbo Landslide Causes

Slope angle, weather, water content, and human factors like leaking water mains and unstable soil contributed to the Thredbo Landslide.

Landslide Mitigation

Involves identifying cost-effective structural and non-structural options, such as hazard mapping, hard engineering measures like reinforced gabion walls, soil nailing, deep shafts, ground anchor walls, and horizontal drains.

Vulnerability to Landslides

Physical, social, economic, and environmental factors like building on slopes, lack of education, poverty, and soil type increase vulnerability.

Reducing Vulnerability

Conducting soil analysis before construction, public education, building retaining walls, enforcing building codes, and providing incentives for special needs individuals.

Landslides and floods in Abidjan

Abidjan, with a population of five million, faces common landslides and deadly floods during the rainy season from April to October, impacting informal settlements.

Impact on cocoa production in Ivory Coast

Heavy rains in Soubre, the heart of the Ivorian cocoa belt, may lead to reduced crop output in August and September due to potential damage to young pods and flowers on trees.

Concerns of farmers in Soubre

Farmers in Soubre fear that the heavy rains could cause harvested cocoa beans to become mouldy as the cloudy weather hampers the drying process, potentially leading to flooded farms.

Rainfall data in Soubre

Reuters data indicates that Soubre experienced 229.3mm (9 inches) of rainfall in the week to Wednesday, significantly exceeding the five-year average by 175.2mm (6.89 inches).