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movements attributed to deep processes of the Earth’s heat engine: The interior is hot, space is cold; the second law of thermodynamics states that this gradient will drive spontaneous convection processes in pursuit of equilibrium. The motion of lithospheric plates is a considerable consequence of thermally-driven mass movements on the Earth.
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Transform movements are horizontal movements of tectonic plates that slide past one another without creating or destroying crust. This type of movement can lead to significant geological features and events, including earthquakes, as the stress builds up when plates get stuck before eventually releasing. Understanding transform movements is crucial for grasping how these interactions shape ...
Tectonics is the study of the origin and arrangement of the broad structural features of Earth’s surface including: Folds and faults. Mountain ranges. Continents. Earthquake belts. The basic premise of plate tectonics is that the Earth’s surface is divided into a few large, thick plates that move slowly and change in size. 2.
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Movement in narrow zones along plate boundaries causes most earthquakes. Most seismic activity occurs at three types of plate boundaries—divergent, convergent, and transform. As the plates move past each other, they sometimes get caught and pressure builds up. When the plates finally give and slip due to the increased pressure, energy is ...
- Distribution
- Divergent Boundary
- Convergent boundary
- The formation of fold mountains
- Earthquakes
- Causes
- Effects of an earthquake
- Factors affecting the impact of an earthquake
- Earthquakes and volcanoes in LEDCs
- The effects of an earthquake or a volcano in LEDCs
- Volcanoes
- Facts:
- How volcanoes form
- Inside a volcano
- Different types of volcano
- Shield volcanoes
- Effects of volcanic eruptions
- Positive and negative effects of an eruption
- Short-term responses and results
- Case study: Mount St Helens 1980 – an MEDC
- Short term responses and results
- Long term responses and results
- Predicting and preparing for volcanoes
- The key techniques for monitoring a volcano
- Preparing for an eruption
- Predicting and preparing for earthquakes
The Earth's crust is broken up into pieces called plates. Heat rising and falling inside the mantle creates convection currents generated by radioactive decay in the core. The convection currents move the plates. Where convection currents diverge near the Earth's crust, plates move apart. Where convection currents converge, plates move towards each...
At a divergent or constructive boundary the plates are moving apart. The plates move apart due to convection currents inside the Earth. The Helgafjell volcano on Westmann Island, Iceland As the plates move apart (very slowly), magma rises from the mantle. The magma erupts to the surface of the Earth. This is also accompanied by earthquakes. When...
At a convergent or destructive boundary the plates are moving towards each other. This usually involves a continental plate and an oceanic plate. The oceanic plate is denser than the continental plate so, as they move together, the oceanic plate is forced underneath the continental plate. The point at which this happens is called the subduction zon...
The formation of fold mountains Where an area of sea separates two plates, sediments settle on the sea floor in depressions called geosynclines. These sediments gradually become compressed into sedimentary rock. When the two plates move towards each other again, the layers of sedimentary rock on the sea floor become crumpled and folded. Eventually ...
Earthquakes are caused by the release of built-up pressure inside the Earth's crust. An earthquake's power is measured on the Richter Scale using an instrument called a seismometer. The effects of an earthquake can be devastating - they can destroy settlements, change landscapes, and cause many deaths.
An earthquake is the shaking and vibration of the Earth's crust due to movement of the Earth's plates (plate tectonics). Earthquakes can happen along any type of plate boundary. Earthquakes occur when tension is released from inside the crust. Plates do not always move smoothly alongside each other and sometimes get stuck. When this happens pressur...
Clearing rubble after an earthquake, Bhuj, India Earthquakes can destroy settlements and kill many people. Aftershocks can cause even more damage to an area. It is possible to classify the impacts of an earthquake, by taking the following factors into account: short-term (immediate) impacts long-term impacts social impacts (the impact on people) ec...
Distance from the epicentre – the effects of an earthquake are more severe at its centre. The higher on the Richter scale, the more severe the earthquake is. Level of development – MEDCs are more likely to have the resources and technology for monitoring, prediction and response. Population density (rural or urban area). The more densely populated ...
LEDCs often suffer more from the effects of volcanoes and earthquakes than MEDCs
Communication systems may be underdeveloped, so the population may not be well educated about what to do in the event of a volcanic eruption or an earthquake. Construction standards tend to be poor in LEDCs. Homes and other buildings may suffer serious damage when a disaster occurs. Buildings collapsing can cause high death tolls. Evacuation and ot...
Volcanoes form when magma reaches the Earth's surface, causing eruptions of lava and ash. They occur at destructive and constructive plate boundaries. The immediate effects of volcanic eruptions can be devastating, but they may be beneficial in the long term.
Key things you should know about volcanoes: A volcano is formed by eruptions of lava and ash. Volcanoes are usually cone shaped mountains or hills. When magma reaches the Earth's surface it is called lava. When the lava cools, it forms rock. Volcanic eruptions can happen at destructive and constructive boundaries, but not conservative boundaries....
Magma rises through cracks or weaknesses in the Earth's crust. Pressure builds up inside the Earth. When this pressure is released, e.g. as a result of plate movement, magma explodes to the surface causing a volcanic eruption. The lava from the eruption cools to form new crust. Over time, after several eruptions, the rock builds up and a volcano fo...
The magma chamber is a collection of magma inside the Earth, below the volcano. The main vent is the main outlet for the magma to escape. Secondary vents are smaller outlets through which magma escapes. The crater is created after an eruption blows the top off the volcano. An eruption occurs when pressure in the magma chamber forces magma up th...
Volcanoes can be described in terms of activity and can be: Still active and erupt frequently. Dormant (temporarily inactive but not fully extinct). Extinct (never likely to erupt again). Volcanoes can also be described by their shape or type:
The characteristics of a shield volcano Shield volcanoes are usually found at constructive boundaries. They are low, with gently sloping sides. They are formed by eruptions of thin, runny lava. Eruptions tend to be frequent but relatively gentle.
Helgafjell Volcano, Iceland Volcanic eruptions can have a devastating effect on people and the environment. However, unlike earthquakes, volcanoes can also have a positive impact on an area. These positive impacts can help to explain why people choose to live near volcanoes.
Positive Negative The dramatic scenery created by volcanic eruptions attracts tourists. This brings income to an area. Many lives can be lost as a result of a volcanic eruption. The lava and ash deposited during an eruption breaks down to provide valuable nutrients for the soil. This creates very fertile soil which is good for agriculture If the as...
Evacuation. Abandonment of the capital city. The British government gave money for compensation and redevelopment. Unemployment rose due to the collapse of the tourist industry. Long-term responses and results An exclusion zone was set up in the volcanic region. A volcanic observatory was built to monitor the volcano. New roads and a new airport we...
Map showing location of Mount St Helens Mount St Helens is on the plate boundary between the Juan de Fuca plate and North American plate. When it erupted it permanently changed the surrounding landscape.
Communications such as roads and bridges were repaired. People were rehoused.
Soil fertility improved due to the ash deposits. The volcano is now more carefully monitored. Tourism has increased, boosting the local economy. It's not possible to prevent earthquakes and volcanic eruptions. However, careful management of these hazards can minimise the damage that they cause. Prediction is the most important aspect of this, as th...
Unfortunately volcanic eruptions and earthquakes cannot be prevented. Managing hazards such as earthquakes and volcanoes can be done by: prediction and preparation. As a volcano becomes active, it gives off a number of warning signs. These warning signs are picked up by volcanologists (experts who study volcanoes) and the volcano is monitored.
The techniques available for predicting and monitoring volcanic activity are becoming increasingly accurate. Volcanoes such as Mount St Helens in the USA and Mount Etna in Italy are closely monitored at all times. This is because they have been active in recent years and people who live nearby would benefit from early-warning signs of an eruption. ...
detailed plan is needed for dealing with a possible eruption. Everyone who could be affected needs to know the plan and what they should do if it needs to be put into action. Planning for a volcanic eruption includes: Creating an exclusion zone around the volcano. Being ready and able to evacuate residents. Having an emergency supply of basic provi...
Earthquakes are not as easy to predict as volcanic eruptions. However, there are still some ways of monitoring the chances of an earthquake: Laser beams can be used to detect A seismometer is used to pick up the plate movement. vibrations in the Earth's crust. An increase in vibrations may indicate a possible earthquake. Radon gas escapes from cr...
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Brian Dufort, Sally Erickson, Matt Hamilton, David Soderquist and Steve Zigray. World Geography is an introduction to world geography through the lens of physical and human geography. The text explores the basic concepts of geography, its importance, the tools used by geographers, and the importance of thinking globally. Read Download.
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Transform Boundary: Definition And Examples. By. Daniel Nelson. A transform boundary is a place where two of the Earth’s tectonic plates move past one another. As these plates move past one another, the two plates interact and can create cracks or faults within the surrounding area. While this is the basic definition of a transform boundary ...
