Download - Unit 19: Natural Disasters pt 1
Unit 19: Natural Disasters
pt 1
NATURAL DISASTERS• An event that occurs naturally and
affects the earth’s surface and environment– Man made disasters occur as a result of
human error and or accidents
• Can be land, water or weather disasters– Land disasters occur due to movement of
the earth’s land surface• Volcanic eruptions, earthquakes, landslides and
avalanches– Water disasters involve huge amounts of
water moving at a greater speed• Floods, storms and tsunamis
– Weather disasters occur due to extreme changes in weather elements• Tornadoes, droughts, blizzards, heat waves
NATURAL DISASTERS
TYPHOONS
Unit 19: Typhoons
WHAT IS A TYPHOON?• Large tropical storms that produce
strong winds and large volumes of rains
• Occurs during certain periods of the year
• Eye of the typhoon is a low pressure region where the winds spin– Strong winds and rains surround the
eye of the storm
Unit 19: Typhoons
EFFECTS OF TYPHOONS• ON THE ENVIRONMENT
– May cause landslides, uproot trees, – May produce a storm surge (rise in
the water level as the typhoon makes a land fall) which may result to flooding
• ON PROPERTIES– Water and wind damage of properties
such as cars, houses, and even death may result
Unit 19: Typhoons
SIGNS OF AN APPROACHING TYPHOON
• Satellite pictures– Show speed of wind, clouds and
storms– Can estimate the course and strength
of a typhoon• Aircrafts pick up info by flying
close to it• Ships monitor oceanic temp• Weather radars on land
Unit 19: Typhoons
MEASURES TO BE OBSERVED
• Before a typhoon– Turn off and unplug appliances– Secure glass windows– Secure objects which may be carried by the wind– If and when needed, go to an evacuation center– Bring an emergency kit– If not, stay indoors and away from windows– Hide in basements and underground bunkers– Have an adequate supply of clothes, food,
batteries, drinking water; have portable radio
Unit 19: Typhoons
MEASURES TO BE OBSERVED
• During a typhoon– Continue to stay indoors– Monitor radio for updates
Unit 19: Typhoons
MEASURES TO BE OBSERVED
• After a typhoon– Be careful in going around the
premises• Be on the lookout for broken materials,
including electrical lines– Ensure structural integrity of your
house– Stay away from flood waters, if
possible
Unit 19: Typhoons
VOLCANIC
Unit 19: Volcanic Eruptions
ERUPTIONS
VOLCANOES• An opening in the ground though
which lava, hot gases, ash and rocks are released at a great force.
• They are formed when tectonic plates move towards or away from each other
• The PLATE TECTONIC theory explains why plates move
Unit 19: Volcanic Eruptions
HOW A VOLCANO ERUPTS
High pressure and temperature causes magma to force its way out of the crust
Blocked VENT may block the magma
allowing more pressure to build up
When the pressure is great, magma will
shoot itself through the vent and will go
out through the CRATER
Unit 19: Volcanic Eruptions
THE PACIFIC RING OF FIRE•Belt around the Pacific Ocean•Active volcanoes are located due to the active movement of the plates
Unit 19: Volcanic Eruptions
TYPES OF VOLCANOESUnit 19: Volcanic Eruptions
• Erupts regularly in the past and will do
so again in the future
Active
• A currently inactive volcano but still shows signs of
eruptionDormant
• Scientists consider them unlikely to
erupt
Extinct
Taal Volcano Three Sisters in Colorado Cococachi in Equador
DANGERS OF AN ERUPTION
• Explosive (pyroclastic) eruptions may– Eject ash, gas and very big rocks
• Makes breathing difficult• Smell of sulphur is foul
– Hot lava may destroy outlying properties
• Non explosive eruptions may also destroy properties
Unit 19: Volcanic Eruptions
SIGNS OF A VOLCANIC ERUPTION• A volcanic eruption may be predicted
• As magma starts to move– Seismographs and seismometers detect and
record this– Gas and steam emissions – Tremors and bulges
Unit 19: Volcanic Eruptions
MEASURES TO BE OBSERVED
• Before a volcanic eruption– For those living near volcanoes– Keep eye and mouth protection– Put together an emergency kit– Stay away from permanent danger
zones– Do not resist evacuation
• Know evacuation route
Unit 19: Volcanic Eruptions
MEASURES TO BE OBSERVED
• During a volcanic eruption– Stay clear of lava and other pyroclastic
materials– Avoid rivers and other low lying areas
• Route taken by hot lava and lahar (water and mud)
– Protect arms and legs, as well as eyes and mouth
– Close windows and doors to prevent ash from getting in the house
Unit 19: Volcanic Eruptions
MEASURES TO BE OBSERVED• After a volcanic
eruption– Remove ash from
roofs (have adults do this)
– Continue wearing protective gears
– Stay away from rivers which may be routes of lahar
Unit 19: Volcanic Eruptions
sources• gadgets.boingboing.net• wunderground.com• worldatlas.com• pacificislandparks.com• volcanochild.co.uk• Istockphoto.com• ecuador-travel.net• ellerbruch.nmu.edu• eos.higp.hawaii.edu• armageddononline.org• oml13.glogster.com