Hazards and preaparedness

2. VOCABULARY
• Natural hazards - events that occur as part of the natural cycles of Earth
and may cause potential damage to a community.
• An event that causes widespread losses ( human, economic, and
environmental) and disrupts the normal functioning of a community is called
disaster.

3. HAZARDS CAUSED BY GEOLOGIC PROCESSES
• Earthquake
•Volcanic eruptions
•Landslides

4. COMMON GEOLOGIC HAZARDS

5. 1. EARTHQUAKES
•Also known as a quake, tremor or temblor
• is the perceptible shaking of the surface of the Earth, which
can be violent enough to destroy major buildings and kill
thousands of people.
•The plate tectonics theory explains that interaction of plates
occurs on their edges or boundaries.

6. •The Philippines is geographically located near the boundaries
of active tectonic plates. It is specifically near the edge of the
Philippine plate that is constantly pushed by an active Pacific
plate.
•Earthquaketrack.com is a Web site that provides real-time
information on earthquakes whose data are provided by the
United States Geological Survey (USGS).
•According to this site, the Philippines experiences 200 to 250
earthquakes of varying magnitude each year. Most of the
earthquakes have less than 2.0 magnitude which are not
strong enough to cause damage.

8. • MAGNITUDE
-measures the energy released at the source of the
earthquake.
• INTENSITY
- measures the strength of shaking produced by the
earthquake at a certain location.

9. HAZARDS ASSOCIATED WITH
EARTHQUAKES
A. Ground Shaking
-It is the vibration of the ground due to plate movement or
seismic waves during an earthquake.
-Living things may be disturbed by this movement.
-Buildings and other infrastructure can be damaged by the
effect of ground shaking.
-These structures can also be damaged when the ground
beneath them sinks (subsidence) after shaking.

10. EARTHQUAKE IN NEPAL
EARTHQUAKE IN

11. HAZARDS ASSOCIATED WITH
EARTHQUAKES
B. Surface faulting
-The tearing of the ground when the movement of a
fault deep within Earth breaks through to ground
surface.
-Buildings, roads, railroads, tunnels, and pipelines are
susceptible to surface faulting damage.
-Animal habitats may also be destroyed, or worse, lost
due to the breaking of the ground.

12. Russia

13. 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.

14. •According to the Philippine Institute of Volcanology and
Seismology (PHIVOLCS) , the top 10 provinces that are
at risk to earthquakes are the following
1.Surigao del Sur 6. Tarlac
2.La Union 7. Ifugao
3.Benguet 8. Davao Oriental
4.Pangasinan 9. Nueva Vizcaya
5.Pampanga 10. Nueva Ecija

16. 2. VOLCANIC ERUPTIONS
•The location of the Philippines in the Pacific Ring of Fire is
near the subduction zone of the Pacific Plate.
•Subduction zone is the sinking region of a convergent plate
boundary.
•Because of the activities of these plates, the Philippines is
prone to volcanic eruptions.
•According to PHIVOLCS, there are more than 20 historically
active volcanoes in the country that have manifested a
volcanic activity in the last 600 years.

18. LIST OF ACTIVE VOLCANO IN THE
PHILIPPINES
• Mayon in Albay
• Taal in Batangas
• Kanlaon in Negros Island
• Bulusan in Sorsogon
• Smith in Calayan
• Hibok-Hibok in Camiguin
• Pinatubo in Zambales
• Musuan in Bukidnon

19. Other related hazards in volcanic eruptions
1. Lahar flow 4. Ballistic projectiles
2. Ash fall. 5. Emission of volcanic gases
3. Pyroclastic flow 6. Lava flow
• These hazards prompt the evacuation of affected communities
because of the significant changes in the physical and biological
profile of the environment.
• Geohazard maps plotted by PHIVOLCS was used to identify the
location of volcanoes and the possible risks associated with the
activities of these volcanoes.

20. MAYON VOLCANO IN
ALBAY

21. 3. LANDSLIDES
•Occur in sloping terrain.
•Usually, if the soil is not compact and devoid of
vegetation, gravity can drive soil and rocks to slide.
•Natural factors that can induce a landslide are wind
and water.
•It can also be triggered by rainfall or earthquake.

23. 2 TYPES OF LANDSLIDE
a.Rainfall-induced landslide
•In sloping areas, the gravitational descent of loosened soil
makes it possible for landslide to occur.
•This is common in places with tropical climates after very
intense and long rains during the wet season.
•A steep slope with structures has a high vulnerability to
landslides. It increases the chances of structures to slide by
gravitational descent.

24. b. Earthquake-induced landslides
•This type of landslide happens during or after an
earthquake when a piece of weakened landslides off
primarily due to gravity.
•The development of frail rock or soil foundation may
be due to the natural make-up of the soil consisting
of a softer layer beneath solid bedrock; man-made
activities that induce erosion.

25. •Landslides bring about long-term effects not
only on communities but also on the
environment.
•This hazards can lead to a number of fatalities
especially if no disaster reduction plans are in
place.

26. NATURAL HAZARDS IN THE PHILIPPINES
• Magnitude 7.8 earthquake in Northern and Central Luzon (July
16, 1990)
• Magnitude 7.2 earthquake in Bohol (October 15, 2013
• Magnitude 6.9 earthquake in Central Visayas (February 6, 2012)
• Magnitude 7.6 earthquake near Eastern Samar (August 31,
2012)
• Magnitude 7.5 earthquake in Central and Southern Mindanao
(March 5, 2002)
• Magnitude 7.0 earthquake in North Western Luzon (July 27,
2022)