Tectonic Hazards Flashcards
What is a tectonic plate?
A large slab of the Earth’s crust.
What is a plate margin?
Where the plates meet, also known as a boundary
What do tectonic plates move?
Tectonic plates are floating on the Earth’s mantle. The mantle is made up of semi-molten rock and move due to convection currents.
Name the 3 different types of plate boundaries.
Constructive
Destructive
Conservative
What is an earthquake?
An earthquake is the sudden movement of Earth’s crust. Earthquakes occur along fault lines, cracks in Earth’s crust where tectonic plates meet.
Why do volcanoes form?
Volcanoes erupt when molten rock called magma rises to the surface. Magma is formed when the earth’s mantle melts. Melting may happen where tectonic plates are pulling apart or where one plate is pushed down under another. If magma is thick, gas bubbles cannot easily escape and pressure builds up as the magma rises and erupts at the surface.
What is a hot spot?
A hot spot is an area on Earth over a mantle plume or an area under the rocky outer layer of Earth.
Outline the characteristics of the oceanic crust.
Newer/younger
Dense
Can be renewed
Name, date and magnitude of an earthquake in a LIC
Nepal, 2015, 7.8
Name, date and magnitude of an earthquake in a HIC.
New Zealand, 2016, 7.8
Name 3 primary effects of Nepal
9,000 dead
20,000 injured
$5 billion in damage
Name 3 secondary effects of Nepal
18 killed by avalanche on Mt Everest
Landslides stopped emergency aid
13 killed by typhus outbreak
Name 3 immediate responses of Nepal
India and China provided over $1 billion of international aid.
Over 100 search and rescue responders, medics and disaster and rescue experts were provided by The UK along with three Chinook helicopters for use by the Nepali government.
Temporary housing was provided, including ‘Tent city’ in Kathmandu.
Name 3 long term responses of Nepal
Water supply is being restored but 2 years after the event, many people still didn’t have access to clean water.
Heritage sites were reopened in June 2015 to attract tourists back to the area.
The road from Nepal to Tibet was reopened 2 years after the quake but many other routes remain damaged.
Name 3 primary effects of New Zealand
2 people died
Over 50 people were injured
$8.5 billion in damage
Name 3 secondary effects of New Zealand
The earthquake triggered up to 100,000 landslides which blocked major road and rail routes.
A major landslide blocked the Clarence River, leading to flooding and evacuation of 10 farms.
The earthquake generated a tsumani with waves of around 5m, leaving debris up to 250m inland.
Name 3 immediate responses of New Zealand
Tsunami warning issues quickly, and residents of coastal areas were told to move to higher ground.
Hundreds of people were housed in emergency shelters and community centres.
200 of the most vulnerable people were evacuated form Kaikoura by helicopter within 24hrs of the quake.
Name 3 long term responses of New Zealand
$5.3 million of funding was provided by the Kaikoura district council to help with rebuilding the towns water systems and harbor.
Most road and rail routes were repaired and reopened within 2 years.
The Kaikoura Earthquake Relief Fund was set up to help residents who could not afford to buy basic supplies and donations were received from around the world.
How are earthquakes measured?
Seismograph
How are volcanoes measured?
VEI
What are the benefits from living near a volcano?
volcanic rock and ash provide fertile land which results in a higher crop yield for farmers
tourists are attracted to the volcano, which increases money to the local economy
geothermal energy can be harnessed, which provides cheaper electricity for locals
minerals are contained in lava, eg diamonds - these can be mined to make money
How do we monitor volcanoes?
seismometers - used to measure earthquakes occurring near an eruption
tiltmeters and GPS satellites – these devices monitor any changes in landscape. Volcanoes tend to swell near an eruption
looking at the past history of eruptions - scientists can identify patterns of activity
How are earthquake predicted?
Prediction involves using seismometers to monitor earth tremors. Experts know where earthquakes are likely to happen. However, it is very difficult to predict when they will happen. Even looking at the timescale between earthquakes doesn’t seem to work.
How can we protect ourselves from earthquakes?
rubber shock absorbers in the foundations to absorb the Earth tremors
steel frames that can sway during Earth movements
open areas outside of the buildings where people can assemble during an evacuation
How can we prepare for erathquakes?
In earthquake-prone countries, hospitals, emergency services and residents practice for an earthquake. They have drills in all public buildings so that people know what to do in the event of an earthquake. This helps to reduce the impact and increases their chance of survival.
