Chapter 6: Managing natural hazards Flashcards
Q: What materials make up the Earth’s inner core?
A: Iron and nickel.
Q: What is the state of the Earth’s outer core and its temperature range?
A: The outer core is liquid and has a temperature range of 4000 – 5000°C.
Q: What type of materials is the Earth’s mantle composed of?
A: Mainly silicate minerals.
Q: What are some methods to manage drought?
A: Increasing water supplies, water conservation, agricultural improvements, and government stockpiling supplies.
Q: What causes tectonic plates to move?
A: Convection currents in the mantle.
Q: What geological feature can form when two oceanic plates move apart?
A: New basaltic ocean crust, shields or basic volcanoes, and sea-floor spreading.
A: It causes warmer surface waters in the Pacific, leading to droughts in Australia.
Q: What is a constructive (divergent) plate boundary?
A: A boundary where two tectonic plates move away from each other.
Q: What is the focus of an earthquake?
A: The point where the earthquake begins underground.
Q: Why do tropical cyclones not form on the equator?
A: Because the Coriolis effect at the equator is zero, preventing the rotation necessary for cyclones.
Q: What happens at a destructive (converging) plate boundary?
A: Two plates move towards each other, resulting in subduction, formation of an ocean trench, volcanic activity, and sometimes fold mountains.
Q: What is a conservative plate boundary?
A: A boundary where two plates slide past each other, causing earthquakes due to pressure build-up.
Q: Where are volcanoes most commonly found?
A: On constructive and destructive plate boundaries and hotspots.
Q: How can deforestation contribute to flooding?
A: It reduces interception and infiltration, leading to increased overland flow.
Q: What effect does climate change have on droughts?
A: Warmer temperatures can lead to decreased rainfall and increased drought conditions.
Q: What is the epicenter of an earthquake?
A: The point on the surface directly above the focus.
Q: What are some physical causes of flooding?
A: Heavy rainfall, prolonged rainfall, snowmelt, land relief, and saturated soil.
Q: What are some opportunities presented by natural hazards?
A: Fertile soils after volcanic eruptions, geothermal energy, mining opportunities, scenic beauty, and potential employment opportunities.
Q: What is the state of the Earth’s mantle and its temperature range?
A: The mantle is solid but flows slowly due to convection currents, with a temperature range of 1000 – 1200°C.
Q: What are the primary impacts of earthquakes?
A: Damage to buildings, fires, tsunamis, landslides, destruction of farmland, water-related diseases, loss of life, and financial losses.
Q: What ocean surface temperature is needed for tropical cyclones to form?
A: At least 27°C.
Q: What geological feature is associated with a destructive (converging) plate boundary where an oceanic plate is subducted?
A: An ocean trench and potentially a chain of volcanic islands (island arc).
Q: What feature forms when two continental plates converge?
A: Fold mountains.
Q: What happens at a constructive (divergent) plate boundary involving two continental plates?
A: A rift valley may form.
Q: What materials are found in the Earth’s mantle?
A: Mainly silicate minerals.
Q: What measures can be taken to manage volcanic hazards?
A: Prediction using seismometers, satellites, tiltmeters, and gas monitoring; preparation with hazard maps, lava diversion channels, and building reinforcements.
Q: What type of volcano forms at a destructive (converging) plate boundary where oceanic and continental plates interact?
A: An explosive composite volcano.
Q: What is the role of seismometers in earthquake prediction?
A: They measure the magnitude of earthquakes.
Q: What are some impacts of tropical cyclones?
A: Flooding, loss of life, damage to infrastructure, disruption of services, economic loss, and loss of wildlife habitats.
A: Prediction using seismometers, satellites, tiltmeters, and gas monitoring; preparation with hazard maps, lava diversion channels, and building reinforcements.
A: By monitoring rainfall and river discharge, using engineering and soft engineering projects, and adapting infrastructure to mitigate damage.
Q: What is sea-floor spreading?
A: The process where new oceanic crust is formed at constructive plate boundaries as magma rises and solidifies.