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266 Cards in this Set

  • Front
  • Back

a layer of the mantle below the lithosphere comprised of relatively fluid material referrd to as plastic

at the centre of the Earth and is formed of the densest material mainly iron and nickel


two types (oceanic and continental) that have contrasting characteristics such as density and material


layer comprised of the crust and the top layer of the mantle which is made of solid and rigid material

middle layer of the Earth formed of less dense, silicate rocks rich in iron and magnesium and is the second thickest layer

Mohorovic Discontinuity

the boundary between the crust and the mantle named after the scientist who discovered it

the study of the history of the Earth's magnetic field
plate tectonics

theory that the Earth's crust is made up of different rigid plates/slabs that form the lithosphere which float on the asthenosphere powered by convection currents from the Earth's core
sea floor spreading

new crust is formed at plate boundaries causing the sea floor to expand/get wider

name the layers of the Earth

[inner to outer]

what two things is the core made of?

dense rocks containing iron and nickel alloys

what is the mantle made of?

silicate rocks (rocks with lots of silicon in them) and oxygen

explain convection currents

1. radioactive decay of some elements in the mantle and core generate heat

2. lower parts of asthenosphere heat up and rise

3. as they rise, they cool and then sink

4. this current creates drag on the base of the tectonic plates causing movement

how is new crust created?

1. rising current diverge at the base of lithosphere creating drag so plates diverge also

2. magma rises to fill gap and cools to form new crust

3. this is repeated over time

how does sea floor spreading occur?

when new crust is created due to convection currents it causes the sea floor to expand
sea floor spreading creates _____________ ___________ such as the _____________ __________.

mid-ocean ridges

mid-Atlantic ridge

in which year did Alfred Wegener propose the theory of C.D.?


what was Alfred Wegener's supercontinent called?

what evidence did Alfred Wegener base his theory on?

geological evidence and fossils

what issue did Alfred Wegener have regarding his theory?

he couldn't back it up with a mechanism for how the continents moved

what discoveries in the 1950's and 60's provided evidence for continental drift?


sea floor spreading - mechanism

the continental drift theory grew into ___________________________________.

the theory of plate tectonics

geological evidence for the TOPT

- areas of S. America and Africa have rocks of same age and composition and distribution when matched up

- mountain ranges in Scotland and Nordic countries are similar to East coast of N. America

Fossil records supporting the TOPT

- matching fossils can be found when some continents are matched up

- it is unlikely these species migrated or evolved separately

living species supporting the TOPT

- living organisms can also be found on different continents

- unlikely they migrated/evolved

climatology evidence for the TOPT

- glacial deposits in Antarctica, Africa and Australia match in deposition when matched up

- coal deposits formed in tropical conditions found in N. America and Europe suggest they were closer to the equator

palaeomagnetism evidence for the TOPT

- the Earth's magnetic field changes every 200,000 years or so

- when magma erupts from the crust magnetic minerals align themselves with the direction of the magnetic field

- the alternating magnetic stripes show crust is older the further away from the ridge

Pangaea initially split into two parts, what were they called?

Gondwanaland - in the south

Laurasia - in the north

hot spot

a point on the surface of the Earth located above a plume of rising magma, the Hawaiian Islands lie above such a spot
seismic waves

shock waves released by the rupture of rock strata at the focus of an earthquake

what is the temperature of the core?

over 5,000 degrees Celcius
what is the crust made of?

light elements, the most abundant being silicon, aluminium, potassium, sodium and oxygen
the crust varies in thickness - beneath the oceans it could be ___ - ____ km thick whereas below continents it is ____ - ____ km thick

6-10 km

30-40 km

how thick is the lithosphere?

80-90km thick

how many plates is the lithosphere divided into?

seven very large ones and a number of small ones

differences between continental and oceanic crust?

- thickness

- age

- density

- composition


- 30-70km

- over 1,500 million years

- 2.6 (lighter)

- mainly granite, silicon, aluminium, oxygen (SIAL)


- 6-10km

- less than 200 million years

- 3.0 (heavier)

- mainly basalt, silicon, magnesium, oxygen (SIAM)

where plates move apart in oceanic areas they produce _____________ ____________. Where plates move apart in continental crust they produce _______ ___________.

mid- ocean ridges

rift valleys

what is the space between the diverging plates filled with?

basaltic lava
how many layers is the earth divided into when looking at chemical composition?


how many layers is the earth divided into when looking at physical composition?


below the asthenosphere which is less liquid
name given to the total mass of water on the surface of the planet


sometimes uses to describe the part of the earth where life exists
collision margin

two continental plates collide and neither can sink so they are forced upwards

what is created at collision margins?

fold mountains
collision margins can cause....


constructive margin

two plates move away from each other and so the magma moves up to fill the space

what is formed at constructive margins?

mid-ocean ridges and sometimes shield volcanoes

destructive margin

oceanic and continental plates move towards each other and the oceanic gets submerged under the continental where it melts in the subduction zone
what is formed at destructive margins?


fold mountains

deep ocean trenches

transform/conservative margin

two plates slide past each other without creating or destroying any crust but do create pressure

what do conservative margins create?


fault lines - San Andreas

subduction zone

place where two lithospheric plates come together, one sinking underneath the other

island arc

a curved chain of volcanic islands located at a tectonic plate margin, typically with a deep ocean trench on the convex side

rift valley

low land region formed by the interaction of Earth's tectonic plates with a typical formation of long, narrow and deep
how are volcanoes formed at destructive boundaries?

when the oceanic plate is subducted and partially melted, it creates gases and molten rock which move upwards through faults in the continental rock above
how are fold mountains formed?

sediments build up in geosynclines and are slowly forced upwards by the steady advance of the plates forming mountains
the process of mountain building is called...


mantle plume

a large column of hot rock rising through the mantle whose heat causes the lower lithosphere to melt

a flat-topped submarine mountain common in the Pacific Ocean, usually an extinct volcano whose summit did not reach above sea level - eroded submerged seamount

an isolated volcanic peak that rises at least 1000 metres above deep ocean floor

what did Wegener suggest caused the continents to move?

- centrifugal force

- gravitational pull of moon

name two fossils that are biological evidence for the TOPT



collisional boundary
two continental plates moving towards each other

constructive boundary

two plates moving apart

destructive boundary

one continental and one oceanic plate moving towards each other

diverging boundary

plates move apart


plates move towards each other

name 3 plates






the basaltic rock at ocean ridges is ________ allowing sea-water to ___________ through the crust. ____________ in the crust act as vents through which __________ ________ or __________ ________________ shoot out.




hydrothermal jets

black smokers

conservative plate boundary

two plates move side by side either in the same direction or in different ones

how are rift valleys formed?

spreading occurs beneath a major land mass and the heat leads to fracturing and rifting

as the sides of the rift move apart, the central section drops to form a rift valley

how are fold mountains formed?

either when:

- oceanic crust is subducted by continental crust


- two continental plates move towards each other forcing each of them upwards

where is the earth's crust thickest and what can this cause?

at the places where fold mountains are formed and the weight of the sediment can force underlying crust down, forming a 'root'

examples of fold mountains

Himalayas (continental vs. continental)

Andes (oceanic vs. continental)

how are ocean ridges formed?

when two plates diverge, basaltic magma rises to fill the gap and cools forming a ridge on the sea
apart from creating a ridge, what else does the magma at an ocean ridge do?

warms the sea around it enriching it with sulphur producing a rich diversity of life

example of an ocean ridge

mid-Atlantic ridge
how are ocean trenches formed?

found at convergent plate boundaries where dense lithosphere is subducted beneath less dense lithosphere

which zone do ocean trenches occupy?

hadalpelagic zone

what is the hadalpelagic zone?

the deepest zone of the ocean starting at 6,000m

examples of ocean trenches

Mariana Trench in the South Pacific Ocean (Pacific under Philippine plate)
oceanic subduction zones feature a ________ __________ _________ (little hill preceding trench) which marks where the plate begins to ______.

outer trench swell


which type of ocean trenches are asymmetrical?
how are island arcs formed?

they are the result of oceanic/oceanic convergence when one of the plates is forced under the other where it is melted and eventually rises to form volcanoes

examples of island arcs

Aleutian Islands of Alaska

Japanese Islands

the islands form a line because of........and an arc because of.........

the angle and rate of subduction and the consistent depth of where melting occurs

the earth's curved surface

many rift valleys are products of ___________ junctions where 3 tectonic plates meet at about a _______ degree angle



example of rift valley
African Rift Valley which extends 4,000km from Mozambique to the Red Sea

what are hot spots?

regions deep within the earth's mantle from which heat rises through convection allowing rock in the lithosphere to melt as it pushes against weak crust and forms volcanoes

hot spot volcanism occurs at _________ ______

mantle plumes

hot fluid or semi-fluid material below/within the earth's crust from which lava and other igneous rock is formed upon cooling


hot molten or semi-fluid rock erupted from a volcano or fissure

dark fine grained volcanic rock


dark, fine grained, brown or greyish intermediate rock

a pale fine grained volcanic rock of granitic composition

composite volcano

conical volcano built up of many layers of hardened lava, tephra etc

shield volcano

broad domed volcano with gentle sloping sides,
igneous rock

formed through the cooling and solidification of magma or lava


stat of being thick, sticky and semi-fluid in consistency

name the three types of magma




at depth nearly all magmas contain __________ _____ which, as pressure decreases, expands to give magma its _____________ character

dissolved gas


the main gases found in lava are...
H2O and CO2

eruption temperatures of the different lavas in degrees Celciuc

B: 1000 -1200

A: 800 - 1000

R: 650 - 800

viscosity of magma depends on...

the composition and temperature
viscosity levels of magma

B: low

A: intermediate

R: high

name the three ways magma is generated

decompressional melting

transfer of heat

flux heating

in order to generate magma within the solid part of earth, one of two things must happen, what are these two things?

the geothermal gradient must be raised

the melting temperature of rocks must be lowered

decompressional melting

a mechanism to raise the g.g. is convection where hot mantle material rises carrying heat with it. if the g.g. becomes higher than the initial melting temp then partial melting will form.

what type of magma does decompressional melting produce?


at which landforms does decompressional melting occur at?

ocean ridges, hot spots, continental rift valleys

transfer of heat
when magma intrudes into cold crust, it brings heat with it and transfers it to the surrounding rock when it solidifies. if this is repeated, the local g.g. is increased and melting occurs
what type of magma is produced by transfer of heat?


flux melting

if water or CO2 is added to rock, it lowers the melting point and allows magma to be generated

in flux melting, how does water get added to rock?

subduction zones as the plate is force below another, water from the ocean seeps into the pores of the rock and descends into the mantle
magma rises as it is ________ _________ than surrounding rock and so ____________ __________ and gas stored in the magma may not be able to be kept in ________, causing the magmas explosive nature.

less dense

pressure decreases


effusive eruptions
non-explosive eruption
how do effusive eruptions occur?
if the liquid part of the magma has a low viscosity then the gas can expand easily so when it reaches the surface it can burst in a non-explosive eruption

examples of effusive eruptions

pahoehoe flows

A'A' flows

pillow flows

lava flow

which types of magma are associated with effusive eruptions?

basaltic and andesitic

how do explosive eruptions occur?

if the liquid part of the magma has high viscosity then the gas cannot expand easily and so pressure will build inside the gas bubbles meaning explosive bursting will take place when they reach the surface
what types of magma are associated with explosive eruptions?

andesitic and ryholitic

examples of explosive eruptions






at constructive boundaries the magma is ___________ and is formed by ________ __________ and results in _______ eruptions


decompressional melting


at destructive boundaries the magma is ___________ and _________, formed by ________ __________ and _______ ___ _______ resulting in _______ eruptions



flux melting

transfer of heat


name the 4 classifications of volcanic eruptions from smallest to largest




Plinian and ultra-Plinian

lava plateau

horizontal layers of basalt that are formed when lava flows from fissures and solidifies

flood basalt

when erupted cooling basalt lava is formed into distinctive columnar, hexagonal shapes
basic/shield volcano

a broad volcano built up from the repeated non-explosive eruptions of basalt to form low dome/shield, usually with large caldera at top

acid/dome volcano
craggy, steep-sided volcanoes built up of layers of lava typically found near large composite volcanoes

ash and cinder cones

steep conical hills made of loose pyroclastic fragments such as cinders and ash

composite cones

tall conical volcano built up of many layers (strata) of hardened lava, tephra, pumice and ash


huge depressions in the earths crust surrounded by a rim at a higher relief

boiling mud

mud filled with bubbles of sulphur gas that fills up mud pots

formed when large domes of magma cool underground and are only recognisable after overlaying rocks are eroded

what are batholiths typically made up of?

granite with quite large crystals due to slow cooling underground

the area around a ___________ is altered by heat and ___________ to form a ___________ _________



metamorphic aureole

bedding planes

the surface that separates one stratum, layer or bed from another

vertical intrusion that cuts across bedding planes formed when magma intrudes vertically through the crustal rocks

smaller intrusions of magma form a lens shape that intrudes between layers of rock which forces the overlying strata to arch upwards forming a dome which may be exposed by later weathering

metamorphic rock

type of rock that has been changed by extreme heat or pressure causing physical/chemical change

sedimentary rock

rock formed by the deposition of material at the earth's surface within bodies of water


horizontal intrusions along that lines of bedding planes that have vertical cooling cracks

volcanic plug (or neck)

volcanic object created when magma hardens within a vent on an active volcano which can cause extreme build up of pressure
fissure volcano

two plates moving apart and lava is ejected through a fissure/crack

example of a shield/basic volcano

Mauna Loa, Hawaii
example of acid/dome volcano

Mount Pinatubo, Mexico

example of composite volcano

Mount Etna, Sicily

caldera volcano

when the build up of gases is extreme, the resulting explosion removes the summit of the cone, down to the magma chamber creating an opening that can be several km wide

later eruptions can create a new cone in the middle of the old one

example of a caldera volcano

Santroini, Greece

when are intrusive landforms created?

when magma cools and solidifies before reaching the surface
why do intrusive landforms occur?

- because the magma is moving slowly

- the crust is very thick

- if there are only a few weaknesses the magma can move through

why do minerals occur in intrusive landforms?

because the magma cools slowly as it os not exposed to air
batholiths can cause the ground above them to ________

example of sills

Whin Sill, Northern England

example of dykes

Isle of Arran, Scotland

example of batholith
Devon, South England

name the three categories of human responses to volcanic hazards

- modify the event

- modify the loss

- modify vulnerability

modify the event has two sub-categories, what are they?

environmental control

hazard-resistant design

give examples of environmental control in terms of modifying the event

- explosives are used to divert the course of lava (1983 Edna)

- water sprays are used to cool the lava (1973 Eldafell)

- artificial barriers and mounds are created to redirect the flow/escape onto (Hilo, Hawaii and Indonesia)

give examples of hazard resistant design in terms of modifying the event

- design may be used to reduce risk posed by ash fall on roofs to stop them from collapsing in

- can't do much in terms of resisting lava flow, pyroclastic flows and lahars

there are 3 sub-categories in modify vulnerability, what are they?

- prediction and warning

- community preparedness

- land use planning

give examples of prediction and warning in terms of modifying the vulnerability

- various physical processes can be measured for changes

- records of past eruptions can be used to determine what and where

- only 20% of volcanoes are currently managed (mainly MEDCs)

- once scientists know, this information can be relayed to governments and media but is sometimes delayed

give examples of community preparedness in terms of modifying the vulnerability

- evacuations are key to hazard management but require lots of planning and organising e.g. temporary housing and food

- relies on good communication

give examples of land use planning in terms of modifying the vulnerability

- maps enforced through legislation

- many LEDCs don't have maps/past records needed

- can be implemented when a volcanic hazards map is drawn up but this can be a difficult and lengthy process

there are two sub-categories within modify the loss, what are they?

- technical aid

- financial aid

give examples of financial aid in terms of modifying the loss

- losses are shared throughout the whole tax-paying population

give examples of technical aid in terms of modifying the loss

- support from MEDCs

- relief, rehabilitation and reconstruction

mantle plume

a large column of hot rock rising through the mantle whose heat causes the lower lithosphere to melt


a volcano built up of alternate layers of ash and lava


rock fragment and particles ejected during a volcanic eruption

Volcanic Explosivity Index, measures how violent an eruption is on a scale of 0-8

layer of the earth's atmosphere above the troposphere extending to about 50km above the earths surface


(literally 'glacier run') is a type of glacier outburst flood caused by the melting of ice during a volcanic eruption


chemical element found in the ash in Iceland 2010 that contaminated crops and water supplies for both humans and livestock

how quickly did the lava flow move in the Nyiragongo eruption?

40 mph


Goma Volcano Observatory, scientifically monitors the volcanic activity and predicts levels of risk in the area

a sudden violent shaking of the ground, typically causing great destruction, as a result of movements within the crust or volcanic action


the point where the earthquake originated from beneath the crust, the point within the crust where the pressure release occurs

place on the earths surface immediately above the focus which receives the highest amount of energy

primary waves

fastest seismic waves that move through solids and liquids, pushing and pulling the rock so the particles move parallel to the direction of the wave
secondary waves

slower and travel through solids only and move rock up and down or side to side perpendicular to the wave direction

surface waves

travelling through the crust at a low frequency and are almost entirely responsible for the damage caused

name the two types of surface wave




point at which energy is released 0-70km below the surface


point at which energy is released 300-700km deep


a measure used to measure the amount of energy released during an earthquake, usually on the Richter Scale


measurement of how often a recurring event occurs

Richter Scale

a scale measuring the magnitude of an earthquake

name 3 factors of the Richter scale

- doesn't have an upper limit

- its logarithmic, each value has a amplitude 10x greater than the previous

- each value represents about 30x more energy released than the previous

Mercalli scale

scale used to measure impacts of earthquakes using observations

what range does the Mercalli scale have?



soil behaves like a liquid due to vibrations or water pressure within the mass of soil particles causing them to lose contact with one another
primary waves are also known as ....

compressional waves because of the pushing an d pulling action they have

love waves

fastest surface wave that moves the ground side to side

Rayleigh wave

surface wave that rolls along the ground like a wave on the ocean moving the ground both side to side and up and down

what percentage of earthquakes occur on plate boundaries?


which two types of plate boundaries generate the biggest earthquakes?

conservative and subduction

name the three types of fault that exist

- normal fault

- reverse fault

- strike slip

normal fault

- found at diverging boundaries

- hanging wall moves down, foot wall moves up

reverse fault

- converging boundaries

- hanging wall moves up, foot wall moves down

strike slip fault

- conservative plate boundaries

- horizontal movement

how is the intensity of an earthquake measured?

- based on effects above ground

- Mercalli Scale

- no mathematical basis - arbitrary ranking

- more meaningful to non-scientists

- eye-witness/observation surveys

how is the magnitude of an earthquake measured?

- amount of seismic energy released

- seismographs

- single instrumentally determined value

what causes earthquakes?

- release of a build up of pressure b/w plates

- movement of a large amount of magma

- hot spots

- mining

- movements of large amounts of water


term referring to earthquakes that can cause tsunamis

distance between one crest/through and the next

wave height

distance between trough and crest

run-up stage

stage where water rushes inland, term also used as a measurement as to how far inland the water went


experienced before the tsunami, the ocean drops back and recedes, happens if trough reaches the land first

offshore topography

the arrangement of natural and artificial features under the ocean off the coast

hydrostatic effects

objects such as boats, vehicles and structures like wooden buildings are lifted and carried in land by the wave
hydrodynamic effects

tearing buildings apart, washing away soil, undermining infrastructure foundations
shock effects

battering by debris carried in the wave
give two reasons as to why natural disasters have increased in frequency (1900-2011)

- technological/media advancements

- climate change

- population increase, more people to experience more events

give two reasons as to why natural disasters have increased in terms of estimated damage (1900-2011)

- many happening in MEDCs so more infrastructure is destroyed

- more countries become more developed

- population increases

give two reasons as to why natural disasters have decreased in terms of people reported killed (1900-2011)

- technology advancements

- preparation

- science understanding

natural hazard
a naturally occurring process or event which has the potential to cause loss of life or property


lessen the impact of the result

what percentage of hazard-related deaths occur in LEDCs?

what percentage of hazard-related economic losses occur in MEDCs?


why do people live in hazardous areas?

- unpredictability

- lack of alternatives

- changing dangers

- "it won't happen to me"

- costs vs. benefits

vulnerability depends on...

- wealth

- technical ability

- education

- organisation of society

- health

- age

- resilience

thrust fault

a reverse fault in which the plain is inclined at an angle equal to or less than 45 degrees

Michinoku ALERT 2008

a massive earthquake training drill carried out by the Japan Self-Defence Force (JSDF) based around a 6.0 earthquake involving 18,000 participants in 22 towns

Shinkansen trains

high speed bullet trains in Japan that were fitted with equipment allowing them to stop quickly if earthquakes tremors are detected
Reconstruction Design Council

an advisory panel set up by the Japanese government in April 2011 which advise about how best to rebuild

Special Zones for Reconstruction

the system was designed to reflect the needs and requests of affected communities and offers a range of measures to support reconstruction

Japan Tsunami Appeal

British Red Cross opened an appeal within hours of the disaster with the key aims of emergency healthcare/first aid, distributing relief and kitting out 70,000 temporary homes

Vertical evacuation

strategy for providing high ground for communities that lack natural/accessible high ground, residents evacuate vertically rather than horizontally

Tohoku Sky Village

elevated land based islands have been designed to form entire towns in tsunami affected regions

Tohoku earthquake 2011

- positive immediate response

- aircraft was in the air quickly surveying the areas needing relief quickly

- Fukushima Power Plant established a 20km evacuation zone

Tohoku earthquake 2011

- negative immediate response

- emergency response teams were overstretched and inadequately supplied

- temporary accommodation was of poor quality e.g. no heating or electricity

Tohoku earthquake 2011

- positive long-term response

- by November 2011, the reactors had been cooled and stabilised

- a month after the disaster, the gov. had set up the Reconstruction Design Council

Tohoku earthquake 2011

- negative long-term response

- wiped 5-10% off the Japanese stock market, global concern they will struggle to recover

- port was operating at 68% capacity


shaking levels may be increased in an area, or amplified, because of the sub-/surface topography


what did they do in Haiti?

United Nations Development Programme, works to eradicate poverty and help countries in need, after the Haiti 2010 earthquake they helped to improve the socio-economic impacts, education, HIV/AIDS, water supply and general health care

UN World Food Programme

world's largest humanitarian agency fighting hunger, who have set up school meals programmes, cash for assets programmes, helped with emergency preparedness and nutrition

Haiti Fund
organisation with the goal of soliciting, collecting and otherwise fundraising to provide disaster relief

Life Safe

a system whereby any interior building element is designed to protect and evacuate the building population in emergencies such as earthquakes

vents in the earths surface that emit steam and gases such as CO2 and sulphur dioxide usually found along cracks and fissures
formation of fumaroles

water becomes superheated below ground due to high pressure and temperatures of 100C+ and when it reaches the surface the drop in pressure allows it to vaporise creating steam often accompanied by a roaring sound
example of fumarole

Valley of Ten Thousand Smokes in Alaska

formed after the eruption of Novarupta in 1912 leading to thousands of fumaroles erupting in the valley filling it with steam

gases produced by fumaroles differ depending on _________ and their life span depends on having a ________ heat source under them, such as a ______ _______, which can cause them to last for ____________. Fumaroles are a sign of ______ _____ and often have _______ surrounding them.



magma chamber


active volcanism


like fumaroles but emit sulphurous gases instead

a rare type of hot spring under pressure that intermittently releases hot water and steam

there are three types of geyser...

- cone geyser

- fountain geyser

- perpetual spouter

cone geyser

erupts from cone of siliceous sinter in a steady pattern

fountain geyser

erupts from pools of water intermittently in intense eruptions

perpetual spouter

erupt continuously

each geyser is different in appearance and behaviour due to what three factors?

- geographical location

- underground heat source

- plumbing system

formation of geyser

a tube like hole that extends deep into the earths crust becomes filled with water due to porous rock allowing easy groundwater supply and the water deeper in the hole becomes superheated due to it being closer to the mantle until it begins to boil. some of the water is then forced upwards and the boiling water vaporises into steam which moves rapidly towards the surface forcing it and the water out of the tube in an eruption that lasts until all the water is out of the tube or the temp inside the tube drops below 100C. the systems then recharges and the process begins again.
example of geyser

Old Faithful in Yellowstone National Park, Wyoming, USA is a cone geyser that erupts every 45-125 minutes

hot springs

naturally occurring springs that produce water typically warmer than that of the human body from the earths surface on a regular basis

at a hot spring the water is less ________ so no _____ occur and is rich in _______ such as ______. The water varies in ______ and can be either.....






perfect for bathing or too hot to even enter

formation of hot springs - volcanic

water becomes heated as it comes into contacts with magma and a high geothermal gradient may cause superheating

formation of hot springs - non-volcanic

water becomes geothermally heated by percolating deep enough into the crust to reach heated rocks
example of hot spring

Grand Prismatic Spring is largest in USA and third largest in the world and is surrounded by awesome colours due to the pigmented bacteria sue to the minerals present
mud pots/pools

depressions in areas of geothermal activity filled with boiling mud containing sulphurous gas bubbles that burst on reaching the surface

bursting mud can build up on the side of pools forming _____ _________ that can be up to ____ metres high. The mud is often _____ ____ in colour with ______ spots due to the ______ ______ present and the pools themselves can be _____metres in diameter.

mud volcanoes


light grey


iron compounds


formation of mud pots/pools

surface water collects in an impermeable depression lined with clay and under the depression thermal water causes steam to rise through the rock which heats the collected water. Hydrogen sulphide gives the pool an odour and provides energy to the microbes to allow them to break it down into sulphurous acid which turns the rock into clay creating the mud.

example of mud pots

Waiotapu is an active geothermal area in New Zealand home to many extrusive features
mud volcanoes

volcanoes made in different ways involving geo-excreted liquids and gases from the earth and have temperatures inside them that can be as low as freezing

biggest mud volcanoes are ___km in diameter and ______m in height and the main gas given out is ____ _____ with smaller amounts of ____ and ____ also released. They often spit out liquids with _____ such as ____ suspended in them and are found near subduction zones.



carbon dioxide





example of mud volcanoes

Azerbaijan has the largest concentration in the world with 400 some of which form semi-/permanent islands

formation of mud volcanoes

decompaction occurs causing gases to be created at a higher rate meaning the mud becomes more buoyant. the pressure created by the mud inside the volcano is higher than that on the outside and so it erupts from fissures and cracks taking some gas with it