hazards Flashcards
what are natural hazards
atmospheric, hydrological and geomorphic processes and events in our environment that have the potential to affect people adversely
what is a disaster
a disaster is a sudden catastrophic event that causes serious disruption of the functioning of a community or a society causing widespread human, material, economic and/or environmental losses which exceed the ability of the affected community or society to cope using its own Level of resources
how is a disaster entered into the database of the UN’s International strategy for disaster reduction.
a report of 10 or more people killed
a report of 100 people affected
a declaration of a state of emergency by the relevant government
a request by the national government for international assistance
what are some characteristics of hazards
a physical event such as a volcanic eruption that does not affect human beings is a natural phenomenon but not a natural hazard
a natural phenomenon that occurs in a populated area is a hazardous event
a hazardous event that causes unacceptable large numbers of fatalities and /or overwhelming property damage is a natural disaster
what is the spatial distribution?
the arrangement of geographical phenomena or activities across the earths surface
what is temporal distribution
the distrubution of geographical phenomena over time
what is magnitude
the strength of a hazard, or how large and important a natural hazard event is. Most hazards are measured on a scale
what is duration
the actual length of time that the hazard event occurs
what is frequency
refers to how often a hazard event occurs in a particular area/country
what is probability
the chance of an event or action occurring
what is proximity
the closeness or distance from the source or origin of the hazard
what is mitigation
the implementation of the strategies to eliminate or minimise the severity of a hazard or similarly adverse occurrence
what is the scale of spatial impact also known as
as the extent
what is geomorphic hazard
geomorphic hazards are caused by movement within the earths crust
what are atmospheric hazards
atmospheric hazards are those hazards that are created from atmospheric and/or weather processes.
what are hydrological hazards
hydrological hazards are driven by the hydrological processes in the water cycle.
what is a volcano
a volcano is a vent on the earths surface that allows magma to escape from the interior, causing an eruption of lava and gas into the atmosphere and surrounding environment
what are hot spots
these are hot areas inside the Earth where magma plumes continually rise to form a volcano
what are the three different types of volcanos
shield volcano- the magma is very hot and runny, eurptions are gentle and often
composite volcano- the magma is cooler and sticky, with explosive eruptions
caldera volcano- no build up of materials, vent unsupported and collapses
how is the magnitude of volcanic eruptions is measured
using a volcanic explosively index (VEI)
what are earthquakes
earthquakes are seismic waves of energy radiating from faults in all directions, resulting in violet shaking of the Earth’s oceanic and continental crust
what are landslides
a landslide is the movement of mass rock, soils and debris down a slope under the influence of gravity
how can landslides be categorized
as being geomorphic hazard, but its origins can also be hydrologic
what are tropical cyclones also known as
tropical cyclones also known as hurricanes or typhoons depending on the location of the event.
describe how cyclones form
they are caused by a tropical disturbance, which enables the wind to evaporate water from the ocean, and the warm air to rise, causing an intense low-pressure system to build.
surrounding air that exerts a higher pressure then fills the space, the low-pressure system continues to build and spin driven by the heat energy from the ocean
what temperatures do cyclones need to form
26.5
what natural hazard is most frequently
floods
what are floods
floods are defined as the invasion of water in a normally dry area of land. this can be caused by the overflow of inland or tidal water or runoff of surface waters generally due to heavy rainfall
what factors contribute to flooding area
intensity and duration of rainfall over the catchment area
capacity of catchment
weather conditions prior to rainfall event
ground cover
urbanisation
soil type
topography
tidal influences
what are the two types ecological hazard
biological hazards
human hazards
what is a epidemic
a sudden increase in the number of cases of a disease above that would normally be expected in that area
what is a pandemic
when a epidemic spreads over a different area for example several countries or continents