The document discusses different types of volcanic hazards and landslides. It recalls various hazards caused by volcanic eruptions such as lava flow, ashfall, pyroclastic flows, lahars, volcanic gases, and volcanic landslides. It defines landslides as the downward movement of soil, debris, rock, and garbage down a slope due to driving forces exceeding resisting forces. Common causes of landslides include steep slopes, weak geological materials, deforestation, excess loading, water leakage, earthquakes, and human activities. It also introduces Varnes' classification system for landslides, which describes the material type and movement type.
2. RECALL
•hazards that comes with volcanic eruptions – lava
flow, ashfall, pyroclastic flows, lahar, volcanic gases,
volcanic landslide, ballistic projectiles, and tsunami
– and became aware of the dangers that each
hazard can cause to persons and communities.
3. What is Landslide?
•is the very slow to rapid
downward movement of a big
bulk of soil, debris, rock, and
garbage down a slope.
4. •This happens when the driving force
(the force that cause the slope to
move) is greater than the resisting
force (the force that stabilize the
slope and prevent movement).
5. • Some of the reasons why driving force dominates
are steepness of the slope, weakness or weathering
of geological materials, deforestation, too much
loading on the slope, and water leakage from
utilities.
• It can also be triggered by extreme rainfall which
saturates the slope with water, vibrations caused
by earthquakes, and human activities.
6. VARNES’ CLASSIFICATION
•most prominent system of classifying landslides
•utilizes two terms: the first term describes the
material type and the second term describes the
type of movement. Combining the two terms gives
classifications.
