Volcano, vent in the crust of Earth or another planet or satellite, from which issue eruptions of molten rock, hot rock fragments, and hot gases. A volcanic eruption is an awesome display of Earth’s power. Yet, while eruptions are spectacular to watch, they can cause disastrous loss of life and property, especially in densely populated regions of the world.

1. Let's
talk
about
"Geological Hazards"

2. Geological Hazards
–Geological hazards
are natural
phenomena that cause
major problems all
over the world.

3. Other Geological Hazards
and their Causes
–Discussed below are
other geological hazards
and their causes as defined
by the US Geological
Science (USGS)

4. Rainfall
Induced Landslide
–A landslide is a
massive outward
and downward
movement of
slope- forming
materials.

5. Causes of
Landslide
–Landslides occur
when the slope
changes from a stable
to an unstable
condition.

6. ★loss or absence of vertical vegetative structure,
soil nutrients, and soil structure (e.g. after a
wildfire).
Natural causes of landslides
include:
★groundwater (pore water) pressure acting to
destabilize the slope.
★erosion of the toe of a slope by rivers or ocean
waves.

7. ★weakening of a slope through saturation by
snow melt, glaciers melting, or heavy rains.
★earthquakes adding loads to barely stable
slope.
★earthquake-caused liquefaction
destabilizing slopes.
★volcanic eruptions.

8. Houses and vehicles are buried under a debris of logs and earth
close to the shore of Real town, Quezon province on 06 December
2004 following the flash flood and landslides. Thousands were left
homeless and about 1,400 dead and missing from the two storms.

9. Landslides are also aggravated by
human activities, such as:
★deforestation, cultivation and construction,
which destabilize the already fragile slopes.
★vibrations from machinery or traffic.
★blasting (e. g. as miners normally do).
★earthwork which alters the shape of a slope, or
which imposes new loads on an existing slope.

10. ★construction works, agricultural
or forestry activities (e. g. logging)
which change the amount of water
infiltrating the soil.
★in shallow soils, the removal of
deep-rooted vegetation that binds
colluvium to bedrock (e. g. kaingin
farming system).

12. ★The negative economic effects of landslides include the
cost to repair structures, loss of property value,
disruption of transportation routes, medical costs in the
event of injury, and indirect costs such as lost timber and
lost fish stocks.
Effects of Landslides
★Landslides cause property damage, injury and
death and adversely affect a variety of resources.

13. Sinkholes are common where the rock below the land
surface is limestone, carbonate rock, salt beds, or rocks
that can naturally be dissolved by groundwater
circulating through them.

14. Types
of
sinkholes
Dissolution
sinkholes
Cover-subsidence
sinkholes
Cover-collapse
sinkholes

15. Dissolution of the limestone
or dolomite is most intensive
where the water first
contacts the rock surface.
Dissolution
sinkholes

16. Rainfall and surface water
percolate through joints in the
limestone Dissolved carbonate
rock is carried away from the
surface and a smal depression
gradually form.
On exposed carbonate surfaces, a
depression may focus surface
drainage, accelerating the
dissolution process. Debris carried
into the developing sinkhole may
plug the outflow, ponding water and
creating wetylands.

17. Cover-subsidence sinkholes
tend to develop gradually where
the covering sediments are
permeable and contain sand.
Cover-
subsidence
sinkholes

18. A column of overlying sedi-
ments settles into the
vacated spaces (a process
termed "piping").
Granular sediments spall
into secondary openings in
the underlying carbonate
rocks.

19. Dissolution and infilling
con- tinue, forming a
noticable depression in the
land surface.
The slow downward erosion
eventually forms small sur- face
depressions I inch to several feet in
depth and diameter.

20. Cover-collapse sinkholes may
develop abruptly (over a
period of hours) and cause
catastrophic damages.
Cover-
collapse
sinkholes

21. Sediments spall
into a cavity.
As spalling continues, the
cohesive covering sedi- ments
form a structural arch.

22. The cavity migrates up-
ward by progressive
roof collapse.
The cavity eventually
breaches the ground sur-
face, creating sudden and
dramatic sinkholes.

23. New sinkholes have been correlated
to land-use practices, especially
from groundwater pumping and
from construction and development
practices
Sinkholes
can be
human-
induced

24. The following are some
of the observable signs
that a landslide is
possible to occur in a
particular area:
Signs of
Impending
Geological
Hazards

25. A.Landslid
e
1.Earlier Landslide
as an indicator
2.Tension
Cracks
3.Things Moving
4.Water Doing Something
Different

26. –Observing old landslides is
a good indication that the
area has unstable geology,
and that more landslides
are likely in the future.
1.Earlier Landslide
as an indicator

27. 2.Tension
Cracks
– are created by the
stress of geological
material pulling apart.

28. 3.Things
Moving
–Observable movement
and deformation of things
are also indicators of an
impending landslide.

29. –another warning
sign for a landslide
is changes in water
flow.
4. Water Doing
Something Different

30. B.Sinkholes
-rarely strike without giving
some warning in the surrounding
environment or in a nearby
home.Here are some signs to
watch for they may indicate a
problem about the present and
imminent danger of sinkhole:

31. ★Trees or fence posts that tilt or fall
★Foundations that slant
★New small ponds that appear after rain
★Cracks in the ground
★Sudden drainage of a pond
★Rapid appearance of a hole in the ground
★Dips, depressions, slopes that appear
in a yard

32. ★Dead patches of grass or plants
★Sinkholes in the neighborhood
★Wilted vegetation in a limited area
★Well water that is discolored or
contaminated with debris
★Cracking or buckling of home's
concrete slab
★Presence of odd bugs like slugs and
centipedes in the home

33. ★Earthy odor in home after rain
★New or widening cracks
★Separation between walls and
ceiling or floors
★Cracks in interior walls
★Cracks around door and
window frames
★Cracked grout between tiles
★Cracked grout between tiles

34. ★Cracked tiles
★Stair step cracks in blocks or bricks
★Uneven floors, warping of hardwood, bulging
or sagging sections
★Doors or windows that don't open or close easily
★Cracks in sheetrock near doors or windows
All homes are subject to some
settling characteristics.

35. Precautionary
Measures
-Sinkhole formation cannot
really be predicted, but
there are things people can
watch out for and
precautions that can be
taken.

36. 1.Watch for signs of water disappearing from
the surface (for example, thesudden loss of a
steam or retention pond).
2.If a sinkhole occurs in an area of traffic,
barricade it to prevent motorists or
pedestrians from getting too close to it.
3.Check fields before undertaking
machine-related activities, such as
haying or harvesting.

37. 5.Sinkholes will be more prevalent during times
of increased and rapid rainfall, such as with the
type of rains occurring during a hurricane.
4.Keep tractors and heavy machinery far enough
away from the sinkhole, since the ground near the
edge can easily give way.
6.Call emergency hotlines and advise them of the
sinkhole and of the hole which is near utility lines or in
a roadway.

38. 7.Restrict access to the hole.
8.Don't get too close to or go down into
the hole.
9.Do not allow unauthorized or
inexperienced persons to investigate
the sinkhole.

39. Mitigation Strategies to
Prevent Loss of Lives and
Properties in Case of
Landslide

40. 2.Help prepare the members of the family
for evacuation upon the direction of
proper authorities.
➤ What to do before a
landslide
1.It's good to secure clearance from the
Mines and Geosciences Bureau (MGB) on
status of possible landslides.

41. 3.Maintain a list of contact
numbers during emergencies.
4.Participate in planting grasses
to cover slopes or in building
riprap to prevent soil erosion.
5.Participate in regular drills
on evacuation procedures.

42. 6.Help promote public awareness
and involvement on landslide
mitigation.
7.Help develop family preparedness
and evacuation plan.

43. ➤What to do during a
landslide
1.Evacuate immediately if warned of
an impending landslide or mudflow.
2.Stay away from the path of landslide
debris, or seek refuge behind a sturdy tree
or boulder.

44. 3.Get out of house as soon as
possible when rumbling sounds
are heard from upstream or the
trembling of the ground is felt,
indicating a possible mudflow.
4.Run across a slope, not
downwards.

45. ➤ What to do
after a landslide
1.Examine thoroughly the damaged
parts and utilities of the house before
re-occupying it.
2.Stay away from the landslide area.
There may be danger of additional
landslides.

46. 4.Listen to local radio or television
stations for the latest emergency
information.
5.Help in seeking the advice of a
geotechnical expert to evaluate landslide
hazards or design corrective measures
to reduce landslide risk.

47. THANK YOU!