Hazards Flashcards
What is a natural hazard
An extreme event caused by environmental processes that can cause loss of life, damage to property and disrupt human activity
What is a tropical cyclone
A weather system of very low pressure formed over the tropical seas and involving strong winds and heavy rainfall
Eye of a tropical storm
Very low pressure, clearer skies, temperature warmer, calm
Vortex of a tropical storm
Dense cloud, violent wind in gusts, thunderstorm and torrential rain
Edge of a tropical storm
Pressure higher, temperature higher, less cloud and wind and rain
Hurricanes characteristics
Warm, moist air from tropical seas (27 degrees)
Warm sea and calm winds coming from different directions - low wind sheer
Cumulonimbus clouds (anvil shaped)
Moves towards coast at 20-50km/h
Storm surge (abnormal rise of water) at 5-8m
Winds at 120km/h
How to measure tropical storms
Saffir-Simpson Scale
1 (120km/h) - 5 (250km/h)
How does an imager work
Uses light to take a picture of the earths surface
Good for cloud formations and patterns
How does a sounder work
Sends an infrared sensor that measures temperature
It shows the energy being stored in the tropical storm and therefore intensityb
How does a radar work
It measures reflected sound waves
Shows direction and speed of the objects movement
Balsatic lava vs andestic lava
Balsatic lava is very fluid, 1200 degrees hot and fast travelling
Andestic lava is very viscous, 800 degrees and slow travelling
(Andestic lava could create a volcano plug)
Pyroclastic flow
Hot moving current of ash and gas
Can move at speeds up 450 mph and temperatures can reach 1000 C
Can only occurs when an andestic plug is formed
Gas emissions in volcanos
Sulphur, carbon dioxide and cyanide are released during volcanic eruption (potentially hazardous)
Ash clouds in volcanos
Ash is thrown into the air during violent eruptions
Causes damage by blanketing everything
Lahars in volcanos
A mudflow causes by water and debris mixing
Hot muddy flow at 90mph
Calderas in volcanos
Calderas are large and circular volcano depressions formed when magma is withdrawn or erupted from a shallow underground magma reservoir
How to measure volcanos
VEI (volcanic explosivity index)
Exponential scale
How to measure a volcano about to erupt
Thermometer (satellite/airplane/helicopter) - temperature
Spectrometer - gas emissions
Geological history
Tilt meter - land deformation
What is an earthquake
A sudden and brief period of intense shaking of the ground
What is the focus
The centre of the earthquake
Shock waves travel outwards