D.1 Geographical systems

Question 1

a mechanism of plate movement is convection currents, can you explain what this is?

Answer 1

the transfers of heat via movement of magma in the earths crust

Question 2

a mechanism of plate movement is subduction, can you explain what this is?

Answer 2

when a tectonic plate is forced underneath another tectonic plate into the mantle at a convergent plate boundary.

Question 3

a mechanism of plate movement is rifting at plate margins, can you explain what this is?

Answer 3

the creation of a crack or fault line in the earths crust as the lithosphere is extended and stretched

Question 4

one of the secondary hazards of the characteristics formed by volcanic eruptions is pyroclastic flows, what are they?

Answer 4

a rapidly moving mixture of hot gasses, rocks and lava that is produced when a volcano errupts

Question 5

one of the secondary hazards of the characteristics formed by volcanic eruptions is lahars, what are they?

Answer 5

a flow of volcanic debris that has mixed with water and mud.

Question 6

what is liquefaction?

Answer 6

when a saturated land surface changes composition moving from a solid to a liquid temporarily due to seismic activity in the earths crust.

Question 7

what are transverse faults?

Answer 7

when rocks move in opposite direction to one another creating tension and a release of seismic energy.

Question 8

what drives the tectonic movement within the earths crust?

Answer 8

the earth is a systems that is constructed from a serise of layers, each of these layers have different compositions, and it is the interaction between between these layers that drive the process of tectonic movement within the earths crust.

Question 9

what is it that affects the overlying lithosphere and what is the consequence?

Answer 9

convention currents with in the mantle, this ensures that tectonic plates coverage, diverge or compress against each other.

Question 10

what happens when any of the type of movements occur?

Answer 10

it often results in the formation of various landforms and the creation of hazardous events.

Question 11

what is an example of tectonic movement causing an earthquake and volcanic erruption?

Answer 11

When an oceanic crust converges against continental curst, the oceanic tectonic plate (a denser rock type) is subjected or forced underneath the continental plate into the mantle.

This creates friction between the plates and eventually leads to seismic energy being released, subsequently an earthquake occurs, the land mass on the continental plate is forced to compress and fold mountains are formed.

Plumes are formed as the oceanic plate melts in the mantle. These plums under pressure, will make their way to the surface via weakness in the continental plate.

Upon reaching the surface, a volcanic eruption will occur.

Question 12

what is a divergent plate margins and can you give examples? and why is it?

Answer 12

It is where tectonic plates move away from each other such as The North American plate and the Eurasian plates.

This is due to convenient currents in the mantels, which means magma can rise and solidify, which means that the sea floor spreads as the plates move apart under the Atlantic Ocean.

Underwater shield volcanoes can be formed, which may reach above the water level over time due to further eruptions.

Question 13

a mechanism of of plate movement is internal heating, can you explain what this is?

Answer 13

the heat generated within the Earth’s interior due to radioactive decay of elements like uranium, thorium, and potassium. This heat contributes to the convective currents in the mantle, driving the movement of tectonic plates.

Question 14

a mechanism of plate movement is plums, can you explain what this is?

Answer 14

rising columns of hot mantle material from deep within the Earth’s mantle. These plumes can cause volcanic activity and may influence plate movement by creating hotspots or mantle upwellings.

Question 15

what are the three characteristics formed by the volcanic eruptions you need to be aware of?

Answer 15

shield, composite and cinder

Question 16

a characteristic of a volcano is a shield, what is this?

Answer 16

a broad, gently sloping volcano characterized by non-explosive eruptions, often with low-viscosity basaltic lava flows.

Question 17

a characteristic of a volcano is a composite, what is this?

Answer 17

a composite volcano is a tall and steep-sided volcano characterized by a combination of explosive eruptions and the eruption of viscous lava flows, often resulting in a conical shape.

Question 18

a characteristic of a volcano is a cylinder, what is this?

Answer 18

small fragments of volcanic rock and ash ejected during explosive volcanic eruptions. These fragments a can accumulate around a volcanic vent, forming a cone-shaped hill or feature known as a cinder cone.

Question 19

what are the secondary hazards of volcanic eruptions?

Answer 19

pyroclastic flows, lahars, landslides

Question 20

one of the secondary hazards of the characteristics formed by volcanic eruptions is landslides, what are they?

Answer 20

A landslide is a mass movement of material, such as rock, earth or debris, down the slope of a hill or cliff.

Question 21

what are the thee characterises of earth quakes you need to be aware of?

Answer 21

depth of focus, epicentre and wave types

Question 22

one of the three characteristics of earth quakes was depth of focus, what is this?

Answer 22

It is a measure of how deep within the Earth’s crust or mantle the seismic activity originates.

Question 23

one of the three characteristics of earth quakes was the epicentre of focus, what is this?

Answer 23

it is the point on the Earth’s surface directly above the earthquake’s focus, where the seismic waves are first felt or detected. It’s the location where the earthquake’s effects, such as shaking, are most pronounced.

Question 24

what are waves and what are their different types?

Answer 24

Primary Waves (P-Waves): P-waves are the fastest seismic waves and are compressional in nature. They travel through solids, liquids, and gases and are the first to be detected during an earthquake.

Secondary Waves (S-Waves): S-waves are slower than P-waves and are shear waves that move in a side-to-side, or perpendicular, motion. They do not travel through liquids or gases.

Surface Waves: Surface waves are slower than P-waves and S-waves and travel along the Earth’s surface. There are two main types of surface waves:
Love Waves (L-Waves): Love waves have a side-to-side motion and are responsible for horizontal ground shaking.

Rayleigh Waves (R-Waves): Rayleigh waves have both vertical and horizontal motion and cause rolling and swaying of the ground.

Question 25

what are the human triggers of earth qaukes?

Answer 25

dam building, resource extraction

Question 26

can you expand of dam building as a human trigger of earth quakes?

Answer 26

Dam building can trigger earthquakes due to the immense weight of reservoirs, which can induce stress and potentially cause fault slip, leading to seismic activity.

Question 27

can you expand on resource extraction as a human trigger of earth quakes?

Answer 27

Resource extraction, especially activities like mining and drilling for oil and gas, can trigger earthquakes. These activities can alter subsurface pressures and stress, potentially destabilizing geological formations and leading to induced seismic events.

Question 28

what are the associated secondary hazards for earthquakes?

Answer 28

tsunami, landslides, liquefaction, transverse faults

Question 29

what is a tsunami?

Answer 29

A tsunami is a powerful, long-wavelength ocean wave capable of causing devastating coastal flooding when it reaches shallow waters.

Question 30

how do we classify mass movemnts?

Answer 30

by their cause (physical and human), liquidity, speed of onset, duration, extent and frequency

Question 31

define a geophysical hazard?

Answer 31

Geophysical hazards refer to natural events where the causal factor is a geological process, examples include earthquakes, mass movements and volcanic eruptions.

Question 32

what is your definition for vulnerability?

Answer 32

The concept of vulnerability refers to the geographic conditions that increase the susceptibility of a community to a hazard.

Question 33

what is your definition for risk?

Answer 33

risk in relation to geophysical hazards can be defined as the likelihood of a hazardous event occurring in a specific area, and the potential negative consequences that may result from that event.

Question 34

what is your definition of resilience?

Answer 34

Resilience in the context of geophysical hazards refers to the capacity of a community or system to withstand, adapt to, and recover from the impacts of hazards, while maintaining essential functions and minimizing long-term damage.

Question 35

what is your definition for adaptation?

Answer 35

Adaptation, in the context of geophysical hazards, is the process of adjusting in advance to reduce vulnerability and minimize the negative impacts hazards on communities and environments.

Question 36

what are some additional human causes of general seismic activity?

Answer 36

Fracking has caused minor earthquakes in areas of Oklahoma, USA.

Mining can also create instability in the earth’s crust. Earthquakes can occure due to the extraction of fluids underground, such as water when mining for coal, because subsidence is created and movment occurs in the crust.

Question 37

what are some physical cuases of mass movment?

Answer 37

weathering, which creates instability and enables different types of mass movement, and seismic energy causes unpredictability in a slope.

Weathering can be categorised as mechanical, chemical or biological.

Mechanical- Freez-thaw.

Chemical- Oxidation

Biological- Chelation

Rain and vegetation loss

Question 38

why is freeze-thaw such a powerful physical cause of mass movement?

Answer 38

it can create instability due to the expansion and contraction when water freezes and melts in cracks and can lead to rock fall on dry, steep slopes. Where there is more moisture to lubricate the surface, a rock slide can occur.

Question 39

what are some different examples of the classifications of mass movements in action?

Answer 39

A rock avalanche is the most rapid type of mass movement and can often travel down hollows where previous avalanches have taken place.

A rotational slip is a concave shape and normally occurs when a weak rock type such as clay becomes saturated. The clay will then slip as it becomes heavy in conjunction with gravity.

Question 40

what is a creep in mass movment??

Answer 40

it is a slow movement that is caused by the expansion and contraction as well as heating and cooling of the soil, as moisture is absorbed and then released during evaporation.

Question 41

what is a slump in mass movement?

Answer 41

a slump occurs when rock or soil falls in blocks independent of a curved slip plane underneath.

Question 42

what is an example where a flow can be differentiated according to the size of the particle involved in the movement?

Answer 42

In a debris flow, more than 50% of the particles are coarser than sand, whereas in a mudflow more than 50% of the particles are finer than sand.

Question 43

what is solifluction?

Answer 43

it is the downward movement of soil over a permanently frozen surface, and it is common where upper permafrost melts and moves over more frozen permafrost underneath.