3. WHY DO YOU THINK THESE
GEOLOGICAL HAZARDS
HAPPEN?
4. THERE ARE TWO TYPES OF
CAUSE IN GEOLOGICAL
HAZARDS NAMELY
• natural cause and human cause
• Natural cause is due to environmental
factors that we can’t predict when it
happens or control, while the
• human cause is due to human
activities.
5. NATURAL CAUSE OF
LANDSLIDES
Earthquake – any seismic
activities or vibration on the
earth's crust can disrupt the
force of friction that holds the
sediment in incline place or
slope.
It can also create a crack in the
sediments to make it easier to
water to seep to the soil.
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6. HEAVY
RAINFALL
– intense rain weakens the
friction of the bedrock and the
sediments and it will carry
some debris together with
water downhill
7. WILDFIRE
– It is a large destructive fire that
happens in the forest, woodland or
brushes it cause landslide
because when the plants are gone
it makes the soil unstable because
plant act as a glue to make the soil
intact and not loosen
8. VOLCANIC
ERUPTION
– volcanoes ash deposit
are prone to erosion and
when it mixes with water it
will create a lahar or a
mudflow landslides
9. HUMAN CAUSE
OF LANDSLIDES
Clear cutting – a method of
timber harvesting that completely
removes the trees to the place
that act as a binder to the soil
Mining, Construction, deep
excavation – destroy the bedrock
and weakens the foundation of
the soil promoting vulnerability of
critical slopes
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10. OTHER CAUSES OF
LANDSLIDESInfluence of slope – the steeper
the slope the more it is prone in
landslides
Lithology – the characteristic of
rock can cause landslide for
example if the rocks in the place
are composed of clay, mica,
calcite, and gypsum this place is
prone to landslides because
these rocks are prone in
weathering.
11. NATURAL CAUSE
OF SINKHOLE
Earthquake – the vibration of the earth’s crust can cause breaking
of rocks resulting in the groundwater to penetrate and dissolving
the mineral
Water - dissolving the minerals in the rock resulting for creating a
crack or gap
Groundwater – lowering the amount of groundwater causes a loss
of support in the soft material resulting in a collapse
12. HUMAN CAUSE OF SINKHOLE
Presentation title 12
• Some activities of human that can break the
bedrock and can lead to sinkhole are the
following:
• Heavy loads on the surface
• Drilling Mining
• Broken water/Drainpipes
• Deep excavation
14. EFFECTS OF
LANDSLIDE/SINKHOLE
• The effects of landslides/sinkhole may vary depending on the
structures of the place or the population where it happens or how
large the area it covered. Here are some effects of
landslide/sinkhole:
• Loss of lives
• Destruction of infrastructure
• Loss of natural resources
• Loss of property value
• Medical cost in the event
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15. • Give some
examples of
how to
prevent the
following
effect
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16. DIRECTIONS: SEARCH THE FOLLOWING REAL-
LIFE EVENT AND WRITE WHAT ARE THE
CAUSE AND EFFECT OF THE FOLLOWING
SCENARIO
• 1. Itogon Landslide
• 2. Valencia, Cagdianao, Province of Dinagat
Islands landslide
• 3. Mayon volcano lahar landslides (November 2006)
• 4. Bohol city sinkholes (October 2013)
• 5. Kabangkalan city negros sinkhole
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17. DIRECTIONS: IDENTITY WHAT TYPE OF CAUSE IN
SINKHOLE ARE DESCRIBING IN THE FOLLOWING
PICTURES. WRITE A SIMPLE DESCRIPTION
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