unit 1, section a Flashcards
the challenge of natural hazards
what is a natural hazard?
is a natural event that has the potential to cause damage, destruction or danger to humans and the surroundings
what is a tectonic hazard?
natural hazards that occur due to tectonic movements, e.g. volcanoes and earthquakes
what is a hazard risk?
the chance that a natural hazard may take place
what are three factors that affect hazard risk?
1) an increase in people vulnerable to the hazard
2) an increase in the frequency or magnitude of a natural hazard
3) a decrease in the amount of people who can help deal with the natural hazard
what are the four parts (layers) of the earth?
inner core. outer core. mantle and crust
what causes tectonic plates to move?
convection currents, in which the hot core causes magma form the mantle and sink towards the core when it cools. it builds pressure and carries the plates with it.
what is the global distribution of earthquakes/volcanoes like?
- not random
- occur in narrow bands on plate margins
- earthquakes found at all 3 types of plate margins; constructive, destructive and conservative
- volcanoes are found at constructive and destructive plate margins
- anomalies found at ‘hot spots’
what happens at a conservative plate boundary?
plates are sliding parallel past each other, causing friction which eventually is overcome causing an earthquake
what happens at a constructive plate boundary?
two plates diverging away from each other; hot magma rises between and cools to from a new plate (shield volcano), causes small, non violent earthquakes and volcanic eruptions
what happens at a destructive plate boundary?
two plates converging towards each other; pressure builds up and the rock fractures causing a violent earthquakes, when oceanic and continental plates meet, the denser oceanic plate subducts, under the continental plate and magma riss through forming composite volcanos
what are the primary effects of an earthquake?
- property is destroyed
- people are injured and killed
- bridges and roads are damaged
- pipes and electric cables broken
what are the secondary effects of an earthquake?
- business reduced and money spent repairing damage, economy slows
- rubble blocks roads slowing down emergency services, furthering casualties
- broken gas pipes and fallen electricity cables can start fires, destroy property and could kill people
- burst water pipes lead to bad sanitation and lack of clean water, could increase chance of infection spreading
what are the primary effects of a volcanic eruption?
- property and farmland destroyed
- livestock and people killed
- air travel halted because of volcanic ash
- water supply is contaminated
what are the secondary effects of a volcanic eruption?
- economy struggles
- emergency services are slowed down because of rubble and ash
- ice melts causing flooding
- tourism increases as people want to visit the volcanic site
- the ah breaks down creating fertile farmland
immediate responses
- issue warnings
- rescue teams search for survivors
- treatment given to those who are injured
- provide shelter, food and drink
- recover bodies
- extinguish fires
