Hello! I've created this PowerPoint presentation as a requisite in Disaster Readiness and Risk Reduction subject during SY 2019–2020. Other Geological Hazards - Bolide Impact - Ground Subsidence - Coastal Erosion Should you need a .pptx file, kindly email me at rd.chrxlr@gmail.com.

1. OTHER GEOLOGICAL HAZARDS
7.1 Bolide Impact
7.2 Ground Subsidence
7.3 Coastal Erosion
REID CHRYSLER C. MANARES

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3. • Happen less frequently and seem less
likely to occur
• Pose largest threats to the existence
of human race
Cretaceous-Paleogene (“K-Pg”)
Mass extinction event that occurred
65 million years ago
Chicxulub Crater
Evidence for the K-Pg extinction
event, located partly on the tip of
Yucatan Peninsula, and partly
underwater in the Gulf of Mexico
A BOLIDE is any extraterrestrial object.
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When an asteroid, a comet, or a
meteoroid hits the Earth’s surface, the
portion of the ground becomes
compressed and deformed.
Rock fragments from impact side or
ejecta, hurl into the atmosphere and
eventually fall back to the ground
around a ball-shaped depression
surrounded by a raised rim.

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Rock fragments from
the impact side
Depression excavated
by the impactor
Large stony and/or
metallic chunks
Location between
Mars and Jupiter
where asteroids are
confined
Combinations of ice, rock
fragments, and dust, may
come from either Oort
Cloud or Kuiper Belt
Stony, iron, and stony-
iron chunks from the
asteroid belt that
travels in outer space
Meteoroids that have
already hit the Earth’s
surface
Meteoroids still in
flight in the Earth’s
atmosphere, give off
a light streak

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Drastic changes in climatic conditions
The prolonged suspension of dust in the
atmosphere coming from the disturbed rock may
prevent isolation and cause an impact winter.
Water vapor, on the other hand, which may
accumulate in large amounts in the atmosphere if
an impact happened in the ocean, can cause
global increase in temperature.
An impact of a bolide greater than 1 km in average diameter may be accompanied by very strong earthquakes
reaching up to magnitude 13 (Richter scale) and, subsequently, aftershocks of gradually decreasing magnitude.

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Wildfires
May also happen via radiation on the intense
heat generated as the bolide travels through
the atmosphere. The smoke from such wildfires
could also add to the dust which are already
preventing the insolation.
An impact of a bolide greater than 1 km in average diameter may be accompanied by very strong earthquakes
reaching up to magnitude 13 (Richter scale) and, subsequently, aftershocks of gradually decreasing magnitude.

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Tsunamis
May happen when a large impact takes place in
the ocean. 1 to 3 km-high tsunamis — more than
enough to flood a significant portion of landmasses
on Earth — are projected for bodies with a 10-km
average diameter.
An impact of a bolide greater than 1 km in average diameter may be accompanied by very strong earthquakes
reaching up to magnitude 13 (Richter scale) and, subsequently, aftershocks of gradually decreasing magnitude.

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Acid rain
Could result from the contamination of water
vapor in the clouds by nitrogen oxides.
Nitrogen and oxygen in the atmosphere are
combined during the shock created by the impact.
An impact of a bolide greater than 1 km in average diameter may be accompanied by very strong earthquakes
reaching up to magnitude 13 (Richter scale) and, subsequently, aftershocks of gradually decreasing magnitude.

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—
The point is that there is a risk and as with any natural hazard, some set
of procedures for prediction, warning, and mitigation should be followed.

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NASA is continuously indentifying and
tracking all Near-Earth Objects (NEO)
which are comets and asteroids that
pose a great threat if possible impact.
As of 2011, NASA has already
identified 911+17 of all the 981+
19 NEOs larger than 1km wide
which are estimated to exist.
5000+ out of 20,000+ mid-sized
(100m—1km in diameter) NEOs have
already been discovered.
A program called Near-Earth Object
Human Spaces Flight Accessible Targets
Study (NHATS) was started by NASA to
identify NEOs.
Knowing the physical characteristics and the
paths of NEOs is important to be able to
predict when they are most likely going to
come close to Earth.

12. Upcoming Deposits
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PREPARATION NO. 2
PREPARATION NO. 1
$186.54

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14. Ground subsidence is the relative
lowering of the Earth’s surface
usually with respect to the mean
sea level. It can be a result of any of
the following: dissolution and
collapse of limestone, excessive
groundwater withdrawal, mining, oil
and gas extraction, earthquakes
and change of season.

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EXCESSIVE
GROUNDWATER
WITHDRAWAL
Also a main cause of
subsidence in PH particularly
in CAMANAVA area
(Caloocan, Malabon,
Navotas, and Valenzuela)
and in a lot of other highly-
populated urban centers.
EARTHQUAKES
Relative subsidence when
measured on the hanging
wall of a normal fault or the
footwall of a thrust or reverse
fault. Subsidence may also
occur during liquefaction.
CARBONATE DISSOLUTION
AND COLLAPSE
A common cause of subsidence
in the Philippines. When acid
water seeps into the ground,
limestone is dissolved little by
little and creates voids.
EXTRACTION OF OIL AND
NATURAL GAS
Although mainly anthropogenic,
the withdrawal of fluids can also
be caused by natural
processes, such as outflow
through springs.

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ISOSTATIC REBOUND
If a large mass is removed,
through weathering and
erosion or melting of large ice
sheet glaciers, uplift takes
place. On the other hand,
areas which receive large
deposits of sediments like
valleys and bodies of water
tend to become even lower in
elevation because of isostatic
subsidence.
UNDERGROUND MINING
METHODS
Sometimes intentionally cause
the collapse of the surface in
which the appearance, amount,
and areal dimensions can be
predicted.
CHANGE IN SEASON
During wet season, clays in the soil tend to expand. But during dry season
these shrink again. This happens over the entire area covered with
significant amount of clay soil and causes the ground to expand and contract
alternatingly.

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Subsidence may not have the terrifying
effects of other natural disasters, but may
last for a long period of time.
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19. Coastal erosion is a natural process
which shapes shorelines by the
wearing away of coastal land or
beaches, mainly by the impact of
waves along the shoreline.

20. The natural process of coastal erosion not
only involves waves.
The sediment redistribution process that
moves water, sand and bigger rock
fragments also involves:
1. Currents
2. Tides
3. Wind-driven water
4. Ice
5. Rainwater
6. Groundwater
REASONS WHY WIND IS ALSO AN AGENT OF
COASTAL EROSION:
Factors such as:
1. Length of fetch
2. Wind direction and speed
3. Wave length, height, and
nearshore water depth
4. Tidal influence
5. Overall strength and duration
of storm
With climate change, the warmer temperature cause extreme weather conditions such
as stronger storms and higher sea levels.

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Construction of structures
including coastal erosion
control structures that
interfere with the natural flow
of costal materials, causing
erosion in adjacent areas of
the shore.
Activities which destroy
natural protective
features such as dunes
and vegetation cover.
Removal of vegetation
cover exposing sediment
to wind and water action.
Concentration of drainage
water flow into the sea
causing erosion of that
part of the coast.
Building activities that
damage natural protective
features.
Shipping and boating
activities producing extra
wave action.

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• When coupled with deposition, coastal erosion creates and continuously modifies the different
landforms of the transitional sedimentary environment.
• Coastal erosion only becomes a concern when it poses as threat to the safety of humans and
infrastructure.
• Coastal erosion is accentuated during storms that carry waves with a lot of energy.
• Coastal erosion could modify the landscape and possibly cause damage gradually over a
season of after many years.
• Coastal erosion could also happen very rapidly, like overnight, when a storm hits an area.
• Coastal erosion impacts humanity and the environment in various ways.

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