Natural hazards Flashcards
What are the differences between natural hazard and natural disaster
The difference between natural hazard and natural disaster is that natural hazard is a potential threat or event, while natural disaster is the actual occurrence of the hazard resulting in significant damage.
What are the two main types of natural hazards?
Geological hazards and meteorlogical hazards
Geological hazards
These are caused by land and tectonic proccesses
Meteorological hazards
These are caused by weather and climate
Examples of geological hazards
Volcano, Earthquake
Examples of meteorological hazards
Heatwave, Cold events (e.g. beast from the east), Drought, Tropical storm, Flooding
Hazard risk
The probability of a hazard causing harmful consequences e.g. loss of life, injuries, damage
How could level of development increase hazard risk?
- Urbanization: More people moving to cities and building more structures can increase the risk from hazards like flooding or earthquakes.
- Land-use changes: As countries develop, changes in how land is used can expose more people and property to hazards like landslides or wildfires.
How could population density increase hazard risk?
- Exposure: When there are more people living in a small area, they are more likely to be affected by hazards like floods, earthquakes, or wildfires because they are closer to the hazard.
- Pressure on resources: When there are more people in an area, there is more demand for resources like water, food, and energy, which can lead to shortages or other problems, especially during times of drought or other environmental stress.
How could magnitude/strength of hazard increase hazard risk?
- Increased impact: Hazards with greater strength can cause more damage to buildings, infrastructure, and people, leading to a greater risk.
- Reduced coping capacity: Communities may be less prepared to cope with hazards that have a higher magnitude or strength, because they may require more resources or expertise to manage effectively.
How could proximity to hazard zones increase hazard risk?
- Exposure: Being close to a hazard zone means there is a higher chance of being affected by hazards like floods, earthquakes, or wildfires.
- Limited options: When people and infrastructure are located in or near hazard zones, there may be limited options for relocation or mitigation measures, which can increase the risk of harm.
Describe the characteristics of each layer of the earth
- Crust: The outermost layer of the Earth that we live on. It is made up of solid rock and is divided into two types: oceanic and continental.
- Mantle: The layer beneath the crust, and the largest layer of the Earth. It is made up of hot, dense rock that is partially molten.
- Outer core: The layer beneath the mantle, and the only liquid layer of the Earth. It is made up of iron and nickel, and its movement creates Earth’s magnetic field.
- Inner core: The innermost layer of the Earth, made up of solid iron and nickel due to the intense pressure. It is the hottest layer, with temperatures up to 5,500 °C.
How do convection currents cause tectonic plates to move?
- Heat from the Earth’s core causes magma to rise up in the mantle.
- The magma cools as it rises, and becomes denser.
- The cooler, denser magma sinks back down towards the core.
- This creates a circular motion called a convection current.
- The convection current moves the tectonic plates on the Earth’s surface, causing them to move and shift over time.
How does ridge push and slab pull contribute to tectonic plate movement?
The movement of tectonic plates is caused by two forces: ridge push and slab pull.
- Ridge push happens when the weight of the new crust at the mid-ocean ridges pushes older crust away.
- Slab pull happens when the older, colder, and denser oceanic crust sinks into the mantle, pulling the rest of the plate behind it.
What are the 3 main types of plate margin and describe the processes taking place
- Conservative boundary: Two tectonic plates move away from each other, creating gap between them. New rock created as magma rises up from mantle to fill gap.
- Destructive boundary: Two tectonic plates move towards each other, the denser oceanic plate will be forced underneath the lighter continental plate. This is called subduction, it can create volcanic activity and earthquakes.
- Conservative boundary: This is where two tectonic plates slide past each other horizontally. This can cause earthquakes, but usually does not create volcanic activity.
Describe the relationship between tectonic plate margins and where volcanoes and earthquakes occur
Volcanoes and earthquakes happen where tectonic plates meet at plate boundaries. The type of boundary determines what kind of volcanic or seismic activity occurs.
Divergent boundaries, where plates move apart, create volcanic activity but fewer earthquakes.
Convergent boundaries, where plates move towards each other, cause both volcanic activity and earthquakes.
Transform boundaries, where plates slide past each other horizontally, typically cause earthquakes but not volcanic activity.
Explain why earthquakes and volcanoes occur at destructive plate margins
Earthquakes and volcanoes occur at destructive plate margins, where two tectonic plates collide. One plate is usually denser than the other, and it sinks below the other plate in a process called subduction. As the denser plate sinks, it gets hot and starts to melt, forming magma. This magma rises to the surface and can cause volcanic eruptions.
At the same time, the plates moving towards each other can cause pressure to build up. When the pressure becomes too much, it is released in the form of an earthquake. The size and strength of the earthquake depend on the amount of pressure that has built up, the speed of the plate movement, and the type of rock involved.
Overall, the movement of tectonic plates at destructive plate margins can lead to both volcanic eruptions and earthquakes.
List 3 primary effects of an earthquake in a HIC
- Structural Damage: Buildings, roads, and other structures can be severely damaged or destroyed, leading to loss of life and economic impacts.
- Human Casualties: Earthquakes can cause injuries and fatalities to people in affected areas, especially if the infrastructure is not built to withstand the earthquake.
- Disruption of Services: Earthquakes can disrupt essential services such as transportation, communication, and utilities (electricity, gas, and water), making it difficult for people to access basic necessities such as food, water, and medical care.
