Hazards Man- made hazards and natural hazards

1. Hazards
CHAPTER III
A hazard is a situation that poses potential threat
to life, health, property, or environment. Most
hazards only have a theor risk of harm but once it
becomes active, it can turn a normal situation into
an emergency. Risk is the probability of a negative
outcome from exposure to a hazard. (Breeding, 2011)

2. Types of
hazard
01 Natural
02
technological
or human-made

3. Naturally - occuring phenomena
Phenomena caused by rapid or slow onset
events which can be geophysical
(earthquakes, landslides, tsunamis and
volcanic activity), hydrological (floods),
climatological (extreme temperatures,
drought and wildfires). meteorological
(cyclones and storms, storm surge) biological
(disease epidemics and insect/animal plagues).
Natural hazard

4. Caused by humans and occur in or close to
human settlements. Include environmental
degradation, pollution and accidents.
Technological or man-made hazards (complex
emergencies/conflicts, famine, displaced
populations, industrial accidents and
transport accidents.
technological or human-made

5. disaster
A disaster can either be antural or human-made. It is a sudden,
calamitous event that seriously disrupts the functioning of a
community or society and causes human, material, and
economic or environmental losses that exceed the community’s
society ability to cope using its own resources.

6. For example, a rock on top of a hill is a hazard. When small parts of
it are eroded and fall on a nearby house downhill, household
becomes at risk. Bet when the rock is shaken and rolled down hill
damaging many households, endangering the lives of residents,
and limiting their capacity to cope and respond, then the situation
becomes a disaster.
(VULNERABILITY + HAZARD)/CAPACITY = DISASTER
A disaster pccurs when a hazard impacts on vulnerable people. The
combination of hazards, vulnerability and inability to reduce the
potential negative consequences of risk results in disaster.

7. Happens when two blocks of the earth
suddenly slip past one another (fault or fault
plane)
Terminologies:
>Hypocenter - location below the earth’s
surface where the earthquakes starts
>Epicenter - location directly above the earth’s
surface
> Foreshocks - smaller earthquakes that
happen in the same place as the arger
earthquake that follows.
geological hazards
EARTHQUAKE

8. > Mainshock - larger earthquake
> Aftershocks - smaller earthquakes that occur
afterwards in the same place as the mainshock
> Ground shaking - The energy radiates outward
from the fault in all directions in the form of
seismic waves and then shakes the earth as
they move through it. When the waves reach
the earth’s surface, they shake the ground and
anything on it.
geological hazards
EARTHQUAKE

9. > Recording - Earthquakes are recorded using
seismographs which produces a recording
called seismogram.
> Magnitude - size of the earthquake
> Intensity - severity in terms of effects
>Richter scale - devised by the American
seismologists Charles F. Richter and Beno
Gutenberg in 1935 to measure the magnitude of
an earthquake.
geological hazards
EARTHQUAKE

10. - Unusual movement of land
- Can be triggered by earthquakes, volcanic
eruptions, soil saturated by heavy rains, or
groundwater rise
- Can be particularly hazardous due to
frequency of occurrence (Burton, Kates, and
Whites, 1978)
geological hazards
LANDSLIDE

11. Generated by seismic activity under the ocean
floor thereby causing flooding in coastal areas
and can affect areas thousands of kilometers
from the earthquake center.
geological hazards
TSUNAMI OR
SEISMIC SEA WAVES

12. - Happens when the molten rock and gases
escape to the surface of volcanoes.
- May also trigger other natural hazards such as
local tsunamis, floods, and landslides.
- Two classes of eruptions:
a) Explosive eruptions - there is rapid
dissolution and expansion of gas from the
molten rock as it nears the earth's surface;
b) Effusive eruptions - includes the material
flow of mud, ash, lava
geological hazards
VOLCANIC ERUPTION

13. PHIVOLCS (Philippine Institute of Volcanology
and Seismology)
-Is the service institute of the Department of
Science and Technology (DOST)
-Mandated to mitigate disasters that may arise
from volcanic eruptions, earthquakes, tsunami
and other related geotectonic phenomena.
geological hazards
VOLCANIC ERUPTION

14. HYDROMETEOROLOGICAL
HAZARDS
Hydrometeorological hazard are processes or phenomena of
atmospheric, hydrological or oceanographic nature. It may cause
loss of life, inury or other health impacts, property damages, loss
of livelihoods and services, social and economic disruptions, or
even environment damages.

15. HYDROMETEOROLOGICAL HAZARDS includes:
-Tropical cyclones (Typhoons/Hurricanes) - Drought
-Thunderstorms - Heat Waves
-Hailstorms - Storm Surges
-Tornadoes - Avalanches
-Cold Spells - Blizzards
-Heavy Snowfall
-Floods/Flash floods

16. Difference between hurricane and typhoon
> Hurricanes - tropical storms that form over the North Atlantic
ocean and Northeast Pacific
> Cyclones - Formed over the South pacific and Indian Ocean
>Typhoons - are formed over the Northwest Pacific Ocean.

17. how typhoons are formed
Typhoons start off as
a tropical
thunderstorms. The
strong winds pull in
moisture from the
oceans
Thunderstorm
convert the moisture
into heat. The heat
causes more air to
flow to the centre of
the storm causing
evaporation.
All the heat and air
flow toward the eye
creating the
typhoon.

18. parts of a typhoons
Eye - center and the calm part of a
storm
Eye wal - sorrouds the eye and has the
strongest winds (up to 200 miles/hour)
and rains.
Rain bands - area of rainfall where all
the clouds and precipitation are
stretched to form a band-like
appearance.

19. tropical cyclone classification in the philippines
classification
maximum sustained winds
(Based on 10-minutes average)
Tropical Depression 45 to 61 hm/hr
Tropical Storm 62 to 88 km/hr
Severe Tropical Storm 89 to 177 km/hr
Typhoon 118 to 219 km/hr
Super Typhoon 220 km/hr or higher

20. tropical cyclone warning signal in the philippines
Tropical
Cyclone
Warning
Signal
Lead Time
(hrs)
Winds (km/hr) Wind Impact
1 36 30-60 No damage to very light damage
2 24 61-120 Light to moderate damage
3 18 121-170 Moderate to heavy damage
4 12 171-220 Heavy to very heavy damage
5 12 220 Very heavy and widespread damage

21. -Happens when the ocean waves are pushed
towards the shore a forceful wind (intense low
pressure of a tropical cyclone.
- A Super Typhoon can generate storm surge as
high as 20 feet above sea level or more.
- Example: the storm surge in Tacloban on
November 2013 brought by Super Typhoon
Yolanda (Haiyan).
typhoon hazards
STORM SURGE

22. -Occurs along areas with shallow coastlines or
beachfront areas.
- Example: Flooding at Roxas Boulevard in
Manila and the stuctures near Manila Bay on
September 2011 due to Typhoon Pedring
typhoon hazards
COASTAL
FLOODING

23. - Violent rotating column of air extending from
a thunderstorm to the ground
- The wind can go as fast as 300 mph.
- Can destroy large buildings, uproot trees and
hurl vehicles hundreds of yards
typhoon hazards
TORNADOES

24. THANK YOU