3. Common Geologic Hazards
• 1. Earthquake- the plate tectonic theory
explains that interaction of plates occur on their
edges or boundaries.
- the Philippines experiences 200 to 250
earthquakes of varying magnitudes each year.
- most of the earthquake have less that 2.0
magnitude which are not strong enough to cause
damage.
4. Other hazards
a. Ground shaking- the vibration of the ground due
to plate movement or seismic waves during an
earthquake.
b. Surface faulting- the tearing of the ground when
the movement of a fault deep within Earth breaks
through to ground surface.
c. Tsunamis- very high, large waves or seismic sea
waves caused by the sudden movement of the
ocean floor due to earthquakes, volcanic eruptions,
man-made explosions, and on some occasions,
landslides.
5. 2. Volcanic Eruptions
The Philippine belongs to the Pacific Ring of Fire
where volcanic activities are frequent.
The Pacific plate, which is an oceanic subducting
(sinking) plate, moves downward to the mantle
as the other convergent plate
• Subduction zone- is the sinking region of a
convergent plate boundary.
• There are 20 historically active volcanoes in the
country manifested volcanic activity in the last
600 years
6. • Volcanic eruption can be predicted days or even
weeks before it happens.
• PHIVOLCS- Philippine Volcanologist
• Seismic activities such as earthquake and volcaic
eruptions are frequent in areas along the Pacific
Ring of Fire.
7. 3. Landslides
• Occur in sloping terrain
• If the soil is not compact and devoid of
vegetation, gravity can drive soil and rocks to
slide.
• Can be triggered by rainfall or earthquake
8. • a. Rainfall-induced landslides
▫ In sloping areas, the gravitational descent of
loosened soil makes it possible for landslides to
occur.
▫ Common in tropical climates after long heavy
rains and wet season
b. Rainfall-induced landslides
this type of landslide happens during or after an
earthquake when a piece of weakened landslide off
primarily due to gravity.
May be due to natural make up of the soil
consisting of a softer layer beneath solid rocks,
man-made activities that induced erosion, such as
deforestation, excavation, mining and quarrying
or thunder and other vibration from underground.
9. If you are near the shore, drop, cover and
hold until the shaking stops. If the shaking
is severe and lasts for more than 20
seconds, immediately move to higher
ground as big waves or tsunami may be
generated by the earthquake. Make sure
that you move at least 3 kilometres away
from the shore.
Stay away from steep slopes for potential
landslides
10. Managing Volcanic Eruption
• Before:
1. Take note of your surroundings and
announcement by the local government.
2. Gather all family members and develop an
evacuation plan.
3. Put together an emergency supply kits.
4. Put all important papers and documents in an
envelop and carry valuable items in a water
resistant container.
5. Follow instruction provided by the local
government for security and safety.
11. During the Volcanic Eruption
1. Avoid low-lying places because lava and
pyroclastic materials are surely to hear toward
these area due to gravity.
2. Cover head with hard hat for protection from ash
fall and falling debris.
3. Use mask or any protective cloth to cover your
mouth and nose to reduce inhalation of volcanic
ash particles
4. Close all doors and windows to prevent entry of
ashes.
5. Stay indoor or in the evacuation center until
authorities say it is safe
12. Managing Landslides
1. Plant more trees for better compaction of soil
in the vicinity.
2. Build diversion of mudflow or debris flow to
direct it away from your property.
3. Familiarize yourself with your surroundings
and the type of land it is made of.
4. Observe patterns of storm water drainage and
runoff especially in places where they converge
with other sources of runoffs.
16. 5. Fasten shelves and
cabinets to the wall.
6. Repair any cracks in the
ceilings or foundation of the
house.
17. 1. Stay calm and Duck under a sturdy table, cover
and hold.
2. Stay indoor until the shaking stops. Don’t use
elevators.
18. 3. If you smell gas,
immediately leave the
place.
4. Before leaving, make sure
there is no debris that fall to
you.
19. 1. Stay away from buildings,
trees, electrical wires, posts
etc.
2. Drop to the ground until
the shaking stops.
20. 3. If inside the vehicle, find a
clear location and stop.
4. Stay inside and fasten your
seatbelt until the ground stops
shaking
21. 3. Stay away from
damaged building.
4. Inspect your home
structure, utilities and
systems.
22. 6. Clean up spilled
gasoline or
flammable liquids
immediately.
7. Learn about your area’s
seismic building
standards and land use
codes before you begin
any construction.
23. 8. Ask a professional to
strengthen exterior
features and make sure
your home is securely
anchored to its
foundation
24. Hazards Caused by
Hydrometeorological Phenomena
• ITCZ- Inter-tropical Convergent Zone- the
convergence of trade winds results in the rising
of hot air, which intensifies the movement of
winds in the area.
• PAGASA (Philippine Atmospheric, Geophysical
and Astronomical Services Administration)- the
government agency that provides information on
meteorological astronomical and climatological
activities in the Philippines territory
25. Common Hydro-meteorological
Phenomena
• Tropical Cyclone- also known as typhoons are
storm system characterized by rapidly spiralling
storms, low pressure centre and intensely strong
winds.
• Strong winds- strennth of winds can destroy
lightweight structures and uproot plants and
trees.
26. • Heavy rainfall leading to flooding- can lead to
worse problem such as:
1. disruption of commercial and industrial
operations leading to loss of income
2. displacement of affected families
3. Damaged properties resulting from corrosion
and water intrusion;
4. health diseases including leptospirosis and
pathological diseases caused by waterborne
agents.
27. Monsoons
• Are seasonal winds; the Philippines
experience two monsoon every year amihan
and habagat
a. Amihan- or the northeast monsoon is
characterized by cold gusty wind with little
or no precipitation.
- begins in early September up to May or
June.
- Hazards are thunderstorm, lightning, heavy
rainfall, flooding
28. • Habagat- southeast monsoon is
characterized by hot and humid
atmosphere with frequent heavy
rainfall.
- Begins in June and ends in August or
September
- Caused: lack of water for irrigation
can decrease crop
29. • Tornadoes-locally known as ipo-ipo is a rapidly swirling
condensation funnel whose narrow end comes in contact
with the ground
• Hazards:
a. Strong swirling winds- as the wind moves toward the
center (centripical force) the impact breaks objects
along its path
b. Flying debris and dust- fragments of destroyed objects
are hurled away and soil particles scatter around the
area.
c. Fire- tornadoes can destroy power lines and cause fire
