natural hazards/disasters Flashcards
define a natural hazard
a natural hazard is a naturally occurring physical phenomenon caused by either rapid or slow-onset events.
four types of natural harazards
geophysical, (earthquakes, landslides/mudslides, tsunamis, and volcanic activity.)
hydrological, (avalanches and floods.)
climatological, (extreme temperatures, drought, and wildfires. + tropical storms)
biological, (disease epidemics insects/animals plagues.)
define natural disaster + criteria
a natural event such as a flood, earthquake, or hurricane that causes great damage and loss of life.
* report of 100 people affected
* a report of 10 or more people killed
* a declaration of a state of emergency by the relevant government
* a request by the national government for international assistance
define risk
the probability of a hazard event causing harmful consequences (expected losses in terms of death, injuries, property damage, economy, and environment).
define vulnerability
the geographic conditions that increase the susceptibility of a community to a hazard or the impacts of a hazard event.
define hazard perception
the degree to which a hazard is considered to be a threat by different people.
define secondary hazards
indirect effects or secondary effects of a natural hazard occurring after the initial primary hazards.
define adaptation
ways in which human activities/actions are altered to take into account the increasing risk of hazards.
define mitigation
he action of reducing the severity, seriousness, or painfulness of something / to manage risk to make something less severe.
define magnitude
size of a geophysical event.
define Richter scale
define Richter scalea scale that relates to an earthquake’s magnitude based on the size of its seismic waves.
define Mercalli scale
a scale that describes the intensity of an earthquake according to how it feels + the damage it causes.
define Ring of fire
the zone around the pacific ocean where volcanoes are most common. (75%)
define epicentre
where the earthquake is felt most strongly on earth
define vulnerable population
groups of people that require greater protection than other groups such as infants disabled and elderly people.
define focus
where the earthquake originates from
define hot spots
thin places in the earth’s crust where magma can escape
composite volcanoes
along destructive plate margins. the magma is sticky so it forms steep mountain-like volcanoes.
define shield volcanoes
along constructive plate margins, such as Iceland, and also where there are hat sports like the Hawaiian islands. The lava is runny, so it forms a volcano in the shape of a shield, or wide cone with gradual and shallow sides
define crater
the circular depression in the ground caused by volcanic activity
define magma
a very hot liquid/semi-liquid rock located under the earth’s surface.
define lava
the same as magma but after it erupts from a volcano.
define pyroclastic flow
a fast-moving hot gas and volcanoes bits. (very deadly)
define ash cloud
consists of rock, mineral crystals, and volcanic glass, it’s created during eruptions.
how can we predict hazards like earthquakes or tsunamis
using seismographic monitors
what are the earth’s plates made out of? + why do they move
are made of continental crust and oceanic crust, and move due to the convection in the mantle
what are earthquakes caused by?
underground rock suddenly breaking and there is rapid motion along a fault.(sends seismic waves)
