Natural Hazards Flashcards
What is a natural hazard?
Is a natural process which could cause death, injury or disruption to people or damage property
What is a natural disaster?
A natural hazard which has already happened
What is a natural event?
When people or property are not threatened
What is a tectonic hazard?
When the tectonic plates move to cause damage to the land above
What is a atmospheric hazard
Hazards that happen in the atmosphere. E.g. tornado
What is a geomorphological hazard?
Anything that happens on the earths surface . E.g. landslide
What is a biological hazard?
Disease that effect people i many ways. E.g. covid
What is hazard risk?
Is the chance or probability of being affected by a natural event
Factors increasing the risk from natural hazards
Urbanisation
Poverty
Population increase
Capacity to cope
Climate change
Farming
Why do tectonic plates move?
One theory is due to convection currents. Magma in the mantle is heated by the core, it starts to cool and sink back down. This process continues creating a circular motion known a convection currents.
Destructive plate boundary explanation
Two plates are moving towards one another. When the two plates meet a deep ocean trench is formed. The oceanic plate is always pulled under the continental plate. Pressure builds up which causes underwater earthquakes which lead to tsunami. When 2 continental plates move together, fold mountains are formed.
Hazards/ landforms from destructive plates
Earthquakes
Violent eruptions of volcanoes
Tsunami
Examples from destructive plates
Nazca plate(oceanic plate)
American plate( continental plate)
Conservative plate boundary explanation
When two plates are moving past each other. Friction between plates cause earthquakes. Earthquakes happen when the two plates slip and shift
Hazards/landforms conservative plate
Earthquakes
Example of conservative plate
San Andreas Fault
Constructive plate boundary explanation
Two plates are moving apart. Magma is forcing its way before its cooled to form new land. Lava will flow a long way before cooling and will cause shield volcanoes
Hazards/landforms constructive plate
Earthquakes(weak)
Violent volcanoes
Examples conservative plate
North American plate
Eurasian plate
Collision plate boundary explanation
When two plates move together. Made of continental crust because neither plate is denser. No subduction. Land gets crumpled Cushing fold mountains. Pressure builds up and causes earthquakes. Can cause land slides and avalanches due to topography.
Hazards/landforms collision plates
Fold mountains
Earthquakes
Examples collision plates
Indian plate
Eurasian plate
What is an earthquake?
A sudden and violent movement within the earths crust
What is the focus?
Th point at which the rocks moves
The seismic waves start at the focus
Earthquake in collision plate boundaries
Strong magnitude
Pressure builds up between the two continental plates as they push against each. Eventually this becomes top much and the rock gives way releasing the energy as a powerful earthquake.
Earthquake in destructive plate boundary
Strong magnitude
The oceanic plate is pulled under the continental plate. Pressure builds up which causes earthquakes underwater which can lead to a tsunami
Earthquakes in constructive plate boundary
Weak magnitude
The two plates are moving apart which can cause small earthquakes
Earthquakes in conservative plate boundary
Strong magnitude
Friction between the plates can cause earthquakes. They can happen when the 2 plates slip and shift.
Effects of earthquakes(secondary)
Disease
Homeless
Lack of food
Death
Lack of water
Tax increase
Hospitals overcrowded
Looting
Effects of earthquakes(primary)
Buildings collapsing
Roads destroyed
Injuries
Water pipes beak
Crops destroyed
Factors affecting damage cased by earthquakes
Strength of buildings
Location = rural vs urban
Depth of focus
Day. Vs night
Preparation
Response teams
Population density
Magnitude
Case study: Chile
Stage of development
HIC
Case study: Chile
Date
27th February 2010
Case study:Chile
Magnitude
8.8
Case study:Chile
How long did it last for?
3 minutes
Case study:Chile
Type of plate boundary
Destructive plate boundary
Case study:Chile
Any preparations?
Chile had the money to support people and rebuild
Case study:Chile
Effects (primary)
Around 500 people killed and 12000 injured-800000 people affected
220000 homes , 4500 schools, 53 ports, 56 hospitals and other public buildings destroyed
Cost of earthquake estimated at US $5 billion
Case study: Chile
Effects(secondary)
1500 km of roads damaged, mainly by landslides, remote communities cut of for many days
Several octal towns devastated by tsunami waves
Case study:Chile
Response(immediate)
Emergency services acted swiftly. International help needed to supply field hospitals, satellites phones and floating bridges
Power and water restored to 90% of hoes within 10 days
Case study:Chile
Response(long term)
A month after the earthquake, the government launched a housing reconstruction plan to help nearly 200000 households affected by the earthquake
Case study:Nepal
Stage of development
LIC
Case study:Nepal
Date
25th April 2015
Case study:Nepal
Magnitude
7.9
Case study:Nepal
How long did it last for?
50 seconds
Case study: Nepal
Depth of focus
15km
