natural hazards Flashcards
(37 cards)
the probability, threat, or chance that a natural hazard may take place
hazard risk
a natural event that threatens people or has the potential to cause damage, destruction, and death. (a disaster is when such an event actually occurs and causes damage to people, property, infrastructure, industry etc)
natural hazard
tectonic plate margin where two tectonic plates slide past each other - can cause the most powerful earthquakes, because the focus can be very shallow (San Andreas Fault, California, USA)
conservative plate margin
tectonic plate margin where rising magma adds new material to plates that are diverging - magma fills the gap and new oceanic plate is formed (Mid Atlantic Ridge)
constructive plate margin
the process that drives plate tectonic movement - heat from the earth’s inner core is released via convection currents, with super hearted magma rising up through the mantle to the surface creating volcanic activity and plate movement. cooled crust / plate then sinks back down into the mantle
convection
tectonic plate margin where two plates are converging and oceanic plate is subducted. it can be associated with violent earthquakes and explosive volcanoes (Andes mountains, South America, Nazca plate subducts under the South American plate = volcanoes)
destructive plate margin
a sudden or violent movement within the earth’s crust followed by a series of shocks, caused by the rapid release of pressure - it is a seismic event
earthquake
the point on the earth’s surface, directly above the focus, from which seismic waves radiate outwards
epicentre
the point underground where tension has built up, and then suddenly been released ; the point from which an earthquake begins. The shallower the focus, the more powerful the earthquake
focus
later reactions that occur in the weeks, months, years after the event
long-term responses
to reduce the impact of a potential hazard
mitigation (to mitigate)
recording physical changes, such as earthquake tremors or gas emissions around a volcano, to help forecast when and where a natural hazard might strike
monitoring
the margin or boundary between two tectonic plates
plate margin / boundary
actions taken to enable communities to respond to, and recover from, natural disasters, through measures such as emergency evacuation plans, information management, communications and warning systems
planning
attempts to forecast when and where a natural hazard will strike, based on current knowledge. This can be done to some extent for volcanic eruptions but less reliably for earthquakes
prediction
the initial impacts of a natural event on people and property, caused directly by it, for instance the ground buildings collapsing following an earthquake
primary effects
actions taken before a hazard strikes to reduce its impact, such as educating people or improving building design
protection
the after effects that occur as indirect impacts of a natural event, sometimes on a longer timescale, for instance fires due to ruptured gas mains resulting from the ground shaking
secondary effects
the reaction of people as the disaster happens and in immediate aftermath
short-term responses
a natural hazard caused by movement of tectonic plates
tectonic hazards
a rigid segment of the earth’s crust which can float across the heavier, semi molten rock below. continental plates are less dense, but thicker than oceanic plates
tectonic plates
an opening in the earth’s crust from which lava, ash and gases erupt - Pyroclastic flows (burning ash clouds travelling over 100mph) are the greatest threat in the biggest volcanic eruptions
volcano
the effect of an event on the wealth of an area of community
economic impact
the effect of an event on the landscape and ecology of the surrounding area
environmental impact
