An event which has the potential to cause harm to the environment, people or the economy
Natural hazard
An event caused by environmental processes
Disaster
When harm actually occurs to the environment, people or the economy
Natural events only become hazards and disasters due to their impact on people, the environment or the economy
Ways to categorise natural hazards
Magnitude
Frequency
Size
Duration
Location
Tropical cyclone
Rotating, low pressure system (below 950mb)
Characteristics of tropical cyclones
Heavy rainfall
High wind speeds (over 119 kmph)
High waves and storm surges
Tropical cyclone size
Measuring between 100-2000km across the rotating clouds surround a central, calm eye
Tropical cyclone magnitude
Measured on the Saffir-Simpson Scale from 1 to 5
Tropical cyclone location
Develop in tropical regions between 5o and 30o north and south of the equator
Earthquake
Sudden, violent shaking of the ground
Earthquakes occur at all types of plate boundaries
Earthquake epicentre
The point on the Earth's surface directly above the focus
Earthquake focus
The point at which the earthquake starts below the Earth's surface
Earthquake magnitude
Measured on either the Richter Scale or the Moment Magnitude Scale
Earthquake damage
Measured on the Mercalli Scale
Volcano
When magma erupts onto the Earth's surface as lava
Most volcanoes occur at constructive (divergent) and destructive (convergent) plate boundaries
The majority of active volcanoes are located around the rim of the Pacific Ocean called the 'Ring of Fire'
Hotspots
Occur away from plate boundaries and are plumes/columns of magma which escape through the Earth's crust
Volcanic eruption magnitude
Measured on the Volcanic Explosivity Index (VEI)
Tropical cyclone
A rotating, low pressure system that forms over warm tropical waters, with central pressure typically below 950 millibars and requiring ocean temperatures of at least 26.5°C or 80°F to form and sustain itself.