Disaster Risk

1. Department of Environment and Natural Resources
Mines and Geosciences Bureau - X

2. Presidential Directive following the
February 17, 2006 Guinsaugon, St. Bernard,
Southern Leyte Landslide Tragedy

3. OUTLINE
•Geohazards
•The DENR-MGB Geohazard
Mapping and Assessment
Program

5. • geological phenomena
• naturally occurring
• pose danger to people’s lives,
properties, infrastructure, and
communities
• cannot be totally prevented, but can
be mitigated (negative impacts on
people’s lives and properties and
the environment can be reduced)
GEOHAZARDS

6. WHAT is a natural hazard?
A Natural Hazard is an unexpected or
uncontrollable natural event of unusual
magnitude that threatens the activities of people
or people themselves.
A Natural Disaster is a natural hazard event that
actually resulted in widespread destruction of
property or caused injury and/or death.

7. WHY should we be concerned about natural
hazards?
- In every person's lifetime, at least one natural
hazard will likely have some impact on their life.
- In the year 2011, natural hazards caused $380
billion in damage worldwide. Unfortunately, the cost
of natural hazards is increasing dramatically.
- It is important to be aware of natural hazards
because human activities can sometimes increase
how often a natural hazard occurs and how severe a
natural hazard can become.

8. • a supermarket of geohazards
• a natural laboratory of geohazards
• the country that has experienced
the most natural hazards in the
twentieth century

9. Cherry Hills Subd, Antipolo, Rizal, 1999 St. Bernard, Southern Leyte, 2006
Geohazards in the Philippines
Camiguin, 2001
La Trinidad, Benguet, 2009

10. Old river channel
Point
bar
Landslide
deposit
Rice fields
GUINSAUGON, St. Bernard
LEYTE (February 2006)
140 Killed
1,000 missing

11. Geohazards in the Philippines
Bayug Island, Iligan City, 2011 San Roque, Iligan City, 2011
Cala-cala, Cagayan de Oro City, 2011
Canitoan, CDO, 2011

12. Scions Subdivision, Brgy. Canitoan, Cagayan de OroCity, on Nov.
2009.
Iligan City on January 3, 2009
July 17, 2009 - Lower Sugod, Brgy. Sugod,ValenciaCity, Bukidnon
Flood Hazards
Brgy. Canitoan, Cagayan de OroCity on Dec. 17, 2011

13. Geohazards in the Philippines
Northern Luzon Earthquake, July 16, 1990
Ms 7.8
Nueva Vizcaya 1990
Dagupan1990
PHIVOLCS
PHIVOLCS

14. Geohazards in the Philippines
1994 Mindoro Tsunami
1976 Moro Gulf Tsunami

15. Geohazards in the Philippines
Tsunamis due to the 1960 Great Chile Earthquake
In the Philippines, tsunami waves:
3 meters high in Luzon
6 meters in Visayas and Mindanao

16. July 1994
Mt. Pinatubo Eruption
June 13 , 1991
Volcanic Hazards
 pyroclastic surge /ash fall
 lava flow & debris flow
 debris avalanche
 pyroclastic flow
 lateral blast
 bombs and ballistics
 volcanic earthquake
 lahar and flooding
300 Killed; 2.1 M people affected
9,000 Families Displaced by Lahar
800 sq.km. agricultural area lost
Php 1.5 B cost of damages
Hibok-HibokVolcano
1948 - 1953

17. Mt. Hibok-hibok Volcanic Eruption 1948-
1953
Geohazards in the Philippines
Hibok-Hibok, Camiguin, 1951

18. Mt. Pinatubo Volcanic Eruption, 1991
September
1991
LAHAR
Bamban, Tarlac
ASH FALL
Clark Air Base
Geohazards in the Philippines

19. Purok 2A, Brgy. San Pedro, Initao, Mis. Or. on August 2006.
STORM
SURGE
Purok Sampaguita, Brgy. Dampias, Binuangan , Mis. Or.
- Nov. 2007
Brgy.Alangilan, Sagay, Camiguin – Nov. 2007

21. WHY IS THE PHILIPPINES
GEOHAZARD-PRONE?
Philippines
• Lies in Circum-Pacific Ring of
Fire
 ~200 volcanoes, 22 active
20 recorded earthquakes per
day, 200 felt per year, 90
damaging for the past 400
years
Geological setting: complex, tectonically active region

22. WHY IS THE PHILIPPINES
HAZARD-PRONE?
Complex geologic evolution
resulted in varying geomorphology:
•Steep mountainous terrains
(prone to landslides and erosion,
and favorable for fast water flow
downstream)
•Vast plains (prone to flooding)
•Coastal areas (prone to coastal
erosion, storm surge and tsunami)
Geological setting: complex, tectonically active region

23. WHY IS THE PHILIPPINES
GEOHAZARD-PRONE?
Meteorological setting: lies in a tropical region along
the typhoon belt in the Pacific
• Average of 20 tropical
cyclones per year
oWater saturation induces
landslides
oTropical cyclones bring
about strong winds, floods,
storm surges and other
hydrometeorological hazards
•Tropical weather favors fast
rock weathering and erosion

24. WHY IS THE PHILIPPINES
GEOHAZARD-PRONE?
Aggravating factors:
Brgy. Commonwealth, Q.C.
• Deforestation and
denudation
• Siltation of rivers and
streams
• Clogging of waterways
and poor drainage in
urban areas
• Poor selection of
settlement areas
• Improper construction of
houses and buildings

25. WHERE do natural hazards occur?
Everywhere.At least one type of natural hazard
affects every location on Earth.

26. WHO studies and monitors natural hazards?
Several different types of scientists study natural
hazards.
Atmospheric scientists (meteorologists and
climatologists) - study hurricanes, blizzards,
tornadoes, and other weather phenomena.
Geologic scientists focus on landslides,
earthquakes, floods, and other events that
happen at the Earth's surface.

28. GEOLOGY – the science of the Earth, an
organized body on which we live
Main thrust of geology: To understand the changes that take place in and on earth,
and the reasons for those changes. A clear understanding of the earth
processes allow geologists to be among the leading caretakers
of the environment. Conversely, geologists have a direct role in ensuring people’s
safety and well-being and safety from natural processes (e.g., earthquakes, volcanic
eruption, tsunami).

29. • Identify areas that are susceptible to various
geologic hazards, particularly landslides and
flooding
• Increase public awareness to lessen or mitigate
negative impacts of natural disasters
• Identify possible relocation/resettlement sites –
both for those affected and future development
planning
Objectives:

31. HIGH
SUSCEPTIBILITY
- Presence of
active/recent landslides
- Large tension cracks
that would affect the
community
- Areas w/ drainages
that are prone to
landslide damming
- Steep slopes (21-55%
gradient)
MODERATE
SUSCEPTIBILITY
- Areas with inactive &
old landslides
- Small tension cracks
are located away from
the community
- Moderately steep
slopes (15-30%)
- Small, shallow
landslides (< 1.0 m
vertical displacement)
LOW SUSCEPTIBILITY
- Gently sloping to
sloping terrain (5-15%)
- Absence of tension
cracks
LANDSLIDE SUSCEPTIBILITY
PARAMETERS

32. HIGH
SUSCEPTIBILITY
- Areas with greater
than 1 meter flood
height
- Areas usually
flooded for several
hours during heavy
rains
MODERATE
SUSCEPTIBILITY
-Areas with less than
1 meter flood height
- Areas usually
inundated during
prolonged and
extensive heavy
rainfall or extreme
weather condition
FLOOD SUSCEPTIBILITY
PARAMETERS

33. 1:50,000 Scale Maps of Region 10
Cagayan de Oro
Quadrangle

35. MISAMIS ORIENTAL (Sheet 1)

36. MISAMIS ORIENTAL (Sheet 2)

37. CAMIGUIN

38. LANAO DEL NORTE (Sheet 1)

39. LANAO DEL NORTE (Sheet 2)

40. MISAMIS OCCIDENTAL

41. BUKIDNON

42. www.mgb10.com
gdis.denr.gov.ph/mgbviewer
www.mgb.gov.ph
www.denr.gov.ph

43. GEOHAZARDS: NATURAL PROCESSES

44. HOW do we cope with natural hazards?
Mitigation is the process of reducing the severity
of the impact of natural hazards through
planning.
Each hazard requires a specific type of
mitigation.
Ex. Engineering solutions (earthquake-resistant
structures)
Limiting or not allowing human activities