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