Essential Notes - Tectonics - Edexcel Geography A-level

The denser oceanic plate subducts below the continental plate, creating a deep ocean trench and causing explosive volcanoes due to built-up pressure from the melting plate.

A rift valley is formed when any land in the middle of the separation is forced apart.

The stages are Preparedness, Response, Recovery, and Mitigation.

A hazard is a potential threat to human life and property.

The heavier plate subducts, leaving an ocean trench, and built-up pressure causes underwater volcanoes, resulting in the formation of island arcs.

A graphical representation of steps carried out in hazard recovery with a rough indication of time frame.

Volcanoes form where the magma rises.

They are designed to withstand natural disasters, such as aseismic skyscrapers in Japan that can endure earthquakes.

It involves being ready for an event to occur through public awareness, education, and training.

The Pacific Plate is an example of an oceanic plate with a lot of subduction around its edges.

Natural hazards can be hydro-meteorological (caused by climatic processes) or geophysical (caused by land processes).

Both plates build up pressure as they are not as dense as oceanic plates, leading to the formation of fold mountains from the pile-up of continental crust.

It shows that a hazardous event in a low income country will have a longer recovery time.

The gap will most likely fill with water and separate completely from the main island.

By creating stronger sea walls or planting mangrove forests to slow down the wave speed.

Immediate actions such as evacuation, medical assistance, and rescue are taken.

The Richter Scale and the Moment Magnitude Scale are used to measure earthquake magnitude.

Wegner’s Continental Drift Theory supports the Plate Tectonic Theory.

Geophysical hazards occur near plate boundaries.

At constructive plate boundaries, magma rises in the gap left by separating oceanic plates, forming new land when it cools, resulting in the ocean floor spreading.

It shows how quickly an area deteriorates and recovers.

Ridge push is the slope created when plates move apart, where gravity acts upon it, pushing the plates further away.

Seawater was sprayed to cool and solidify the lava flow.

The focus is on long-term responses like restoring services and reconstruction.

The Mercalli Scale measures the intensity of an earthquake based on the damage produced.

Similar fossils found on continents that are now separated by oceans support the idea that they were once connected.

A disaster is when a hazard affects human wellbeing.

Earthquakes can occur near the middle of plates (intraplate) due to pre-existing weaknesses in the crust that become reactivated.

It indicates the scale of the disaster; lower the curve, lower the quality of life.

Slab pull occurs when a plate subducts, pulling the rest of the plate with it into the mantle.

International satellites and aircraft, such as those used by GNS Science in New Zealand, utilize light detection and ranging.

Mitigation involves strategies to lessen the effects of another hazard, such as barriers and warning signals.

It lowers the impact of a disaster, even though resources may not be equally distributed.

The VEI is used to monitor volcanic eruptions by calculating the amount of energy released and the type of eruption.

The depth of seismic waves along the Wadati-Benioff foci shows the subduction of denser basaltic oceanic plates into the upper mantle.

A volcanic hotspot is a localized area of the lithosphere with unusually high temperature due to the upwelling of hot molten material from the core.

Degg’s Disaster Model suggests a disaster only happens when a hazardous event meets a vulnerable population.

Relief, which includes immediate local response like medical aid and search and rescue.

At a conservative plate boundary, parallel plates move in different directions or at different speeds without destroying any plates.

It empowers communities to understand hazards and protection measures, enhancing their resilience.

Governments can modify the event or the resilience/vulnerability of affected people.

Magnitude, speed of onset, duration, frequency, and spatial probability can be used to compare different hazards.

Corruption in government, poor warning systems, and weak community strength.

Sea Floor Spreading occurs when two oceanic plates move away from each other, allowing magma from the mantle to rise and form new crust ridges.

The two types of tectonic plates are oceanic (thin and dense) and continental (thick).

Vulnerability is how susceptible a population is to damage caused by a hazard.

Rehabilitation, where services begin to be restored, temporary shelters set up, and food and water distributed.

They prepare communities for disasters, improving their ability to protect themselves.

Land-Use Zoning involves creating policies on where it is safest to build infrastructure to reduce population and buildings in high-risk areas.

Generally, the less developed a country, the more likely it is to face severe impacts from a tectonic hazard.

Deaths have decreased while economic losses have risen due to increased global wealth.

Palaeomagnetism studies the magnetic patterns of cooled magma, which helps identify the age of oceanic crust by showing the direction of the earth’s magnetic field over millions of years.

Resilience is how well a population can recover from a disaster.

Reconstruction, which aims to restore the area to the same or better quality of life and rebuild infrastructure.

The movement of tectonic plates is caused by convection currents produced by radioactive reactions inside the Earth's core.

Emergency aid and insurance can help communities recover from losses.

Inequality in access to education, housing, healthcare, and reliable income contribute to vulnerability.

It has led to fewer people being affected by disasters.

The risk equation represents the likelihood of humans being affected by a hazard, calculated as Risk = Capacity to Cope x Hazard x Vulnerability.

At destructive and conservative boundaries.

Subduction is the process where oceanic plates are pushed down into the mantle at mid-ocean ridges.

NGOs and insurers play crucial roles in minimizing loss and enhancing community wellbeing.

Urban governments face the challenge of establishing planning measures to reduce vulnerability.

Tectonic hazards like earthquakes occur without warning, making prediction difficult.

Kashmir had 75000 deaths while Izmit had 18000 due to Kashmir's remote mountainous location with poor access to services/infrastructure, hindering capacity to cope.

Plates move at different speeds, building pressure until they crack, causing fault lines and releasing energy in the form of seismic waves.

Japan focuses on policies to reduce vulnerability and increase coping capacity, such as the annual 'Disaster Preparedness Day'.

It caused airline flight disruptions, financially impacting airlines and travelers globally.

In richer countries, there are high financial losses, while poorer countries face severe shocks to community wellbeing and infrastructure.

One plate is forced under the other, getting stuck due to friction, and when they suddenly jerk past one another, energy is released as large seismic waves.

Hydro-meteorological hazards and human-induced disasters like famine.

The Pressure and Release model (PAR) proposes what should be tackled if the risk of a disaster is to be reduced.

Primary Waves cause immediate shock, Secondary Waves arrive seconds later, Love Waves cause horizontal movement, and Rayleigh Waves displace land both vertically and horizontally.

Explosive volcanic threats, landslides, earthquakes, typhoons, tsunamis, drought, and flooding.

The five types of vulnerability are Economic, Environmental, Social, Knowledge, and Physical Vulnerability.

Crustal fracturing, landslides, avalanches, and liquefaction.

By sub-marine earthquakes at subduction zones, causing water displacement and deep trough waves.

They accelerate coastal erosion.

At constructive and destructive plate boundaries, and at hotspots.

The shape of the volcano; super-volcanoes are the most destructive, while composite cones are more dangerous than shield volcanoes.

Lava flows, phreatic eruptions, and pyroclastic flows.

Lahars are mudflows, and jokulhlaups are glacial floods, both secondary hazards from volcanic activity.