Natural Hazards - General Flashcards
What is a hazard?
A hazard is an event with the potential to cause harm to the environment
What is a natural hazard?
A natural hazard is an event caused by environmental processes that would occur even without human interference.
How does a natural hazard become a disaster?
When the potential harm is realized—causing actual damage to the environment
What is the key difference between a natural hazard and a disaster?
A natural hazard is the potential danger; a disaster is the actual occurrence of harm.
How is the potential impact of a natural event determined?
It depends on how the natural event interacts with human populations and built environments.
How do natural hazards affect our environment and society?
They not only can cause immediate physical damage but also trigger long-term social and economic challenges when they become disasters.
What are the four main layers of the Earth?
The Earth is composed of the inner core, outer core, mantle and crust
Describe the inner core of the Earth.
The inner core has a diameter of about 1400 km
What are the characteristics of the outer core?
The outer core is about 2100 km thick
How thick is the mantle and what is its state?
The mantle is approximately 2900 km thick and is in a semi-molten state.
How do oceanic and continental crust differ?
Oceanic crust is thinner (5–10 km) and denser (and is continuously formed and recycled)
What are tectonic plates?
Tectonic plates are the large pieces of the Earth’s crust that float on the semi-molten mantle.
What is the current theory that explains the movement of tectonic plates?
The slab pull theory explains that the movement is driven by the weight of dense oceanic plates subducting and pulling the rest of the plate along.
Where do most earthquakes and volcanos occur?
Most occur along plate boundaries
What is a plate boundary or margin?
It is the area where two tectonic plates meet
Why is the continental crust generally older than the oceanic crust?
Because oceanic crust is constantly created and destroyed through subduction
What are the primary effects of an earthquake?
Primary effects include the direct destruction of buildings and infrastructure
What are the secondary effects of an earthquake?
These include fires due to broken gas or electrical lines
What are the primary effects of a volcanic eruption?
They include the destruction of buildings
What secondary effects can follow a volcanic eruption?
Secondary effects can be ash burying houses and crops
What distinguishes primary effects from secondary effects in tectonic hazards?
Primary effects are the immediate effects and secondary are long term impacts
What are the immediate responses to a tectonic hazard?
Immediate responses involve rescue operations
What are long-term responses after such hazards?
Long-term responses include rebuilding infrastructures
How can damaged transport routes affect post-disaster recovery?
They delay aid distribution and prolong economic disruptions because rescue and recovery teams have difficulty reaching affected areas.
