Geological Hazards

2. GEOLOGICAL HAZARDS

3. GEOLOGICAL
HAZARDS

4. GEOLOGICAL HAZARDS
- A geologic hazard is an extreme natural events in the crust of the earth
that pose a threat to life and property. These hazards are geological and
environmental conditions and involve long-term or short-term geological
processes. Geohazards can be relatively small features, but they can also
attain huge dimensions and affect local and regional socio-economics to a
large extent.

5. The Philippines ranks among the world’s most disaster-prone
countries. It is highly prone to natural disasters, particularly
typhoons, floods, landslides, volcanic eruptions, earthquakes,
and tsunamis, lying as it does in the typhoon belt, in the active
volcanic region known as the “Pacific Ring of Fire,” and in the
geologically unstable region between the Pacific and Eurasian
tectonic plates. Aside from the natural disasters that reap an
especially heavy human toll each year, thousands are also
displaced by human-made disasters like armed conflict and
development aggression. The intensifying effect of climate
change also aggravates the already burdened citizens with the
worsening economic instability worldwide (CDRC, 2014)

6. Different Kind
Of Geological
Hazard

7. VOLCANIC ERUPTION
A volcano is an opening or rupture in
the earth’s surface that allows magma
(hot liquid and semi-liquid rock),
volcanic ash and gases to escape.
They are generally found where
tectonic plates come together or
separate but they can also occur in the
middle of plates due to volcanic
hotspots. A volcanic eruption is when
lava and gas are released from a
volcano—sometimes explosively.

8. Mayon Volcano ( Active Volcano)
Mayon is located southeastern Luzon, Philippines,
dominating the city of Legaspi. Called the world's
most perfect volcanic cone because of the symmetry
of its shape. And it is located on the Ring of Fire, the
chain of volcanoes that sits along the edge of the
Pacific Ocean. There are several subduction zones of
various ages colliding slowly together near the
Philippines, so volcanic activity is frequent there.
Taal Volcano ( Active Volcano )
It is located in the province
of Batangas, the volcano is second
of the most active volcanoes in the
country,

9. On 12 June 2022 at 3:37 PM, an
eruption was detected by the
BVN. The eruption lasted for
approximately 18 minutes and
was recorded as an explosion
type earthquake by seismic and
infrasound instruments, but
could not be visually observed in
the dark of night. The explosion
was felt at Intensity III by
residents of Brgy.

10. The region that are prone
to volcanic eruption are
mostly in the Eastern Luzon,
Central Mindanao, and
parts of the Central Visayas.

11. These are either the sites of the most
active or potentially-active volcanoes,
or their land areas are small and can
therefore be affected entirely by an
eruption. The ten provinces
are Camiguin, Sulu, Biliran, Albay,
Bataan, Sorsogon, South Cotabato,
Laguna, Camarines Sur and Batanes.

12. LANDSLIDES
A landslide is the movement
of rock, earth, or debris down
a sloped section of
land. Landslides are caused
by rain, earthquakes, volcanoes, or
other factors that make
the slope unstable

14. Heavy rainfall and
thunderstorms affected
Northern Mindanao
Region from 17 October
2022. The region's Civil
Defence reported 5
people died after the
rain triggered a landslide
which buried a house in
Malitbog town,
Bukidnon province.

15. So as you can see in this
hazard map, almost part of
the country are prone in the
landslide. The province of
Apayao, Kalinga, Illocus Sur
Mountain, Ifugao, Batangas,
Marinduque, Romblon,
Dinagat Islands, Davao
Oriental, Sultan Kudarat are
the very high chance prone
to landslide Only the small
part of the country are low.

16. Based on Department of Environment
and Natural Resources, Mines and Geo-
Science Bureau (DENR0MGB) had listed
top 10 landslides prone provinces such
as Benguet, Mountain Province, Nueve
Vizcaya, Kalinga Apayao, Southern
Leyte, Abra, Marinduque, Cebu,
Catanduanes, and Ifugao.

17. EARTHQUAKE
An earthquake is the sudden release of
strain energy in the Earth’s crust, resulting in
waves of shaking that radiate outwards from
the earthquake source. When stresses in the
crust exceed the strength of the rock, it
breaks along lines of weakness, either a pre-
existing or new fault plane. The point where
an earthquake starts is termed the focus or
hypocentre and may be many kilometres
deep within the earth. The point at the
surface directly above the focus is called the
earthquake epicentre.

19. The Latest Dangerous Earthquake
That Hit The Philippines:
At 10:59 PM Philippine Standard Time
(PST) on 25 October 2022 (Tuesday), a
strong Magnitude (Mw) 6.4 Earthquake
shook the provinces of Northern
Luzon. The epicenter of the
earthquake is located 5 kilometers
northeast of Lagayan, Abra, at a depth
of 16 kilometers (Figure 1). As of 7:00
PM PST on 26 October 2022, the
DOST-PHIVOLCS Philippine Seismic
Network has recorded a total of 528
aftershocks ranging from M 1.4 to M
4.8. The M6.4 Earthquake occurred
near the epicentral location of the 27
July 2022 Mw 7.0 Earthquake and its
associated aftershocks.

20. The islands in the Philippines
that are prone to
earthquakes are Northern
Luzon, the Eastern Visayas,
Parts of Western and Central
Visayas and almost all region
of Mindanao. Also it is also
included the parts of
Palawan and Mimaropa.

21. The proximity of Southern Mindanao to
Celebes Sea, where undersea earthquakes
frequently occur, makes this part of the
country most vulnerable to tsunamis.
Three of the ten provinces most at risk to
tsunamis are located in Southern
Mindanao, namely Sulu, Tawi–tawi and
Basilan.

22. TSUNAMI ( Tidal Waves)
Tsunamis are giant waves caused by
earthquakes or volcanic eruptions under
the sea. Out in the depths of the ocean,
tsunami waves do not dramatically
increase in height. But as the waves travel
inland, they build up to higher and higher
heights as the depth of the ocean
decreases. The speed of tsunami waves
depends on ocean depth rather than the
distance from the source of the wave.
Tsunami waves may travel as fast as jet
planes over deep waters, only slowing
down when reaching shallow waters.

23. The Philippines is vulnerable to
tsunami due to the presence of
offshore faults and trenches such as
Manila Trench, Negros Trench, Sulu
Trench, Cotabato Trench, Philippine
Trench, and East Luzon Trough.
Tsunamis in the Philippines are rare
but could be devastating.

24. In the past, 38 people drowned as a result of a tsunami
caused by a magnitude 7.1 earthquake in Mindoro on
November 15, 1994. A magnitude 8.1 earthquake on
August 17, 1976 generated by the movement along the
Cotabato trench produced massive tsunami waves as
high as nine meters. Around 8,000 people were killed
or missing and it is known as the most disastrous
tsunami to hit the Philippines in the last four decades.

25. HOW HAZARD
MAP HELPS TO
IDENTIFY
AREAS PRONE
TO HAZARD

26. Volcanic hazard maps are visual,
geospatial depictions of the areas that
could be impacted by various volcanic
phenomena during or subsequent to an
eruption. They are developed to
communicate a complex array of
hazard information to those at risk, or
those responsible for managing those
at risk.

27. Volcanic Hazard maps play
an important role in
identifying the location,
magnitude and
countermeasures to be
undertaken during volcanic
crises. In the planning
process, PHIVOLCS is
expected to arrive at
volcanic hazard maps to
show basic information
about volcanic activity.

28. €
Landslide hazard maps indicate the
possibility of landslide hazard map shows
not only the chances that a landslide
might form at a padownslope a given
distance.
landslides occurring throughout a given
area. An idealrticular place, but also the
chance that it might travel downslope a
given distance.

29. Several kinds of maps are
used to depict danger from
landslides. These maps
might be as simple as a map
that uses the locations of old
landslides to indicate
potential instability, or as
complex as a map
incorporating probabilities
based on variables such as
rainfall, slope angle, soil
type, and levels of
earthquake shaking.

30. The seismic hazard maps address this
need by integrating what scientists have
learned about earthquake sources,
crustal deformation, active faulting, and
ground shaking. This information is
translated into a form that can be used to
reduce the risk from earthquakes and to
improve public safety.

31. The mapped hazard refers to an
estimate of the probability of
exceeding a certain amount of
ground shaking, or ground
motion, in 50 years.
The hazard depends on the
magnitudes and locations of likely
earthquakes, how often they
occur, and the properties of the
rocks and sediments
that earthquake waves travel
through.

32. USEFULNESS
OF HAZARD
MAPS

33. A geological hazard map is a map indicating the
areas that are vulnerable to hazards caused by
earthquakes, volcanic eruptions, and landslides. It is
a tool used by scientists and local government
authorities to anticipate any hazard that a geological
event may bring. It also helps the public be informed
and prepared for the geological hazard.

34. QUIZ TIME!

35. 1. It is an extreme natural events in the crust of the Earth that pose a threat
to life and property.
a. Hazard
b. Geological Hazard
c. Hazard Map
d. All of the above

36. 2. It is an opening or rupture in the Earth’s Surface that allows Magma, Volcanic
ashes and Gases to escape.
a. Volcanic Eruption
b. Landslide
c. Tsunami
d. Earthquake

37. 3. It is a map indicating the areas that are vulnerable to hazard caused by
earthquakes, Volcanic eruption, and Landslides.
a. Hazard
b. Geological Hazard Map
c. Map
d. Geological Hazard

38. 4. It is the movement of rock, earth, or debris down a sloped section
of land.
a. Earthquake
b. Slump
c. Volcanic eruption
d. Landslides

39. 5. It is the sudden release of strain energy in the Earth’s crust.
a. Volcanic Eruption
b. Landslide
c. Tsunami
d. Earthquake

40. Bonus Question: (5 points)
What is the subject handled by Mr. Rodel Azares? ( Acronym is not
allowed)