Transcript Physical and human geography

PHYSICAL AND HUMAN
GEOGRAPHY
NATURAL HAZARDS
 CHALLENGES FOR HUMAN ACTIVITIES.
 NATURAL HAZARD IS A NATURAL EVENT THAT
CAUSES DAMAGE TO PROPERTY, DISRUPTION TO
NORMAL LIFE AND MAY CAUSE LOSS OF LIFE.
 CAUSED BY IMPACT OF NATURAL EVENTS ON
SOCIAL AND ECONOMIC DEVELOPMENT.
NATURAL HAZARD
 RAPID INCREASE IN POPULATION
 URBANISATION (Including shanty towns)
 CHANGING LAND USE IN RURAL AREAS
 NUMBER OF PEOPLE IN POVERTY
 CHANGING NATURAL ENVIRONMENT
TECTONIC HAZARDS
 CAUSED BY PLATE MOVEMENT
TROPICAL STORMS
 WINDS, FLOODS AND STORM SURGES.
 HURRICANES ARE KNOWN AS TROPICAL CYCLONES.
TROPICAL STORMS
 Tropical cyclones are like giant engines that use warm, moist air as fuel.
That is why they form only over warm ocean waters near the equator. The
warm, moist air over the ocean rises upward from near the surface.
Because this air moves up and away from the surface, there is less air left
near the surface.
 Air from surrounding areas with higher air pressure pushes in to the low
pressure area. Then that "new" air becomes warm and moist and rises, too.
As the warm air continues to rise, the surrounding air swirls in to take its
place. As the warmed, moist air rises and cools off, the water in the air
forms clouds. The whole system of clouds and wind spins and grows, fed by
the ocean's heat and water evaporating from the surface
TROPICAL STORMS
FLOODS
 RESULT OF TROPICAL STORMS
 CONTINUOS RAIN
 LOCATION OF SETTLEMENT
 COASTAL FLOODING. HIGH TIDAL RANGE.
FLOODS
 BANGLADESH
FLOODS IN BANGLADESH
 3 LARGE RIVERS:
 GANGES, BRAHMAPUTRA AND MEGHNA.
 MONSOON RAINS
 AVERAGE OF 16 CYCLONES PER YEAR
 80% OF POPULATION LIVE IN RURAL AREAS
 HIGHEST RAINFALL TOTALS IN THE WORLD
 POPULATION GROWTH AND RURAL IMPOVERISHMENT
FLOODS IN BANGLADESH
FLOODS IN BANGLADESH
FLOODS IN BANGLADESH
DROUGHT
 EXTENDED PERIOD OF DRY WEATHER LEADING TO CONDITIONS OF EXTREME
DRYNESS.
 ABSOLUT DROUGHT: 15 CONSECUTIVE DAYS WITH LESS THAN 0.2 MM OF
RAINFALL.
 PARTIAL DROUGHT: 29 CONSECUTIVE DAYS WHERE AVERAGE DAILY
RAINFALL DOES NOT EXCEED 0.2 MM.
 FOREST FIRES
 FOOD SHORTAGES
DROUGHT
RAINFOREST
 OPPORTUNITIES:
FARMING
HYDRO-ELECTRIC POWER
TOURISM
FISHING
MINERAL DEVELOPMENT
RAINFOREST
RAINFOREST
RAINFOREST
REAINFOREST
 HAZARDS:
SURFACE EROSION
SANDIFICATION
CLIMATIC CHANGE
LOSS OF BIODIVERSITY
DESERTS
DESERTS
 HAZARDS:
WEATHERING
FLOODING
EROSION
LANDSLIDES AND ROCKFALLS
DUST STORMS
DESERTS
UNIT 2. LANDFORMS AND LANDSCAPE
PROCESSES
WEATHERING:
Decomposition (chemical breakdown) and disintegration
(physical breakdown) of rocks in situ. Decomposition refers to the
chemical process which creates altered rock substances.
Disintegration produces smaller angular fragments of the same
rock.
PHYSICAL WEATHERING
 FREEZE-THAW
PHYSICAL WEATHERING
 SALT CRYSTAL GROWTH:
PHYSICAL WEATHERING
 DISINTEGRATION
PHYSICAL WEATHERING
 PRESSURE RELEASE