Natural Hazards Flashcards
What is a natural hazard?
A physical event that has the potential to harm humans and property. E.g earthquakes, volcanoes
List some examples of tectonic hazards and the categories they belong to
Tectonic hazards (e.g. earthquake, tsunami, volcanic eruption)
Atmospheric hazards (e.g. hurricane, drought)
Geomorphological hazards (e.g flooding, landslides)
Biological hazards (e.g. forest fires)
What factors affect hazard severity?
-Population density
-Time of day
-Time of year
-Level of development
-Frequency
-Duration
What are convection currents?
When material under the crust gets hotter and rises, then cools and falls back down, in a repeated cycle.
What causes convection currents?
Radioactive decay in the outer core (chemical reactions that occur when iron and nickel collide) that emits heat.
Explain slab pull and ridge push
convection currents push the ridge upwards, while pulling the slab outwards
How hot is the inner core?
5000-6000’C
How wide is the inner core?
2500km
How hot is the outer core?
4000-6000’C
How deep is the outer core?
5150km deep
How hot is the mantle?
1400-3000’C
How thick is the mantle?
2900km
what elements make up the earth’s crust?
oxygen, silicone, aluminium, calcium, iron
how thick is the earth’s crust, and how hot?
90km, 22’C
How thick is the oceanic plate?
5-10km
How thick is the continental plate?
30-50km
Give an example of a constructive plate boundary
Mid-Atlantic Ridge (forms Iceland)
Eurasian and North American plate pull apart
Give an example of a conservative plate boundary
San Andreas Fault Line- San Francisco, LA Pacific Plate moves faster than North American Plate
Give an example of a destructive plate boundary
Atacama trench, Nazca plate subducted by South American plate
What are some of the positives of living near a tectonic hazard?
-fertile soil rich in sulfur, great for farming and growing crops
-tourism industry provides reliable source of income and employment
-Beautiful areas to live in
How do we make a building earthquake proof?
Counter rollers, shock absorbers, bird cage steel frame, reinforced glass windows, helipads, building number, weights on the top of the building
How do we monitor a natural hazard?
Using seismometers and gases emitted by volcanoes
How do we predict a natural hazard?
Use historical evidence, monitor animal behaviour
How do we plan for a natural hazard?
Educate people, train emergency services, have standard procedures implemented, sirens, drills, disaster bags
When does a natural hazard become a natural disaster?
When it has actually happened
