3
WORK AND EXPERIMENTATION TECHNIQUES
In this section, you’ll find out about interesting methods and
procedures for handling instruments and for carrying out your
study. These will help you learn about your surroundings and the
things found there. With these techniques, you will be able to put
into practice what you have learnt in this unit.
FINAL TASK
We will guide you through the task you have to carry out, and
explain how you should present your results. This final task for the
unit is also available in digital format in
Oxford Investigation.
CONSOLIDATION
This is a double page of activities that relate to the unit content.
There are two highlighted sections:
Read and understand science
and
Study skills.
These consist of a summary, a conceptual map
and a glossary of scientific terms.
20
21
1. Internalgeologicalprocesses
1
FINAL TASK
How to locate an earthquake
WORK AND EXPERIMENTATION TECHNIQUES
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Analysisof anaturaldisaster
300 400 500 600 700
70
60
50
40
30
Time (s)
Distance
United States
Tucson
El Paso
Houston
Chihuahua
Rosarito
La Paz
Mazatlán
Acapulco
Mexico
Monterrey
0 100 200 300 400 500 600 700
Km
Materials
❚❚
Three seismograms from the same earthquake from three
different seismic stations
❚❚
Map of the location of the three seismic stationswith a
scale
❚❚
Graphof the calculated distance of thedelay between
the arrivalof P and Swaves
❚❚
Ruler and compass
❚❚
Calculator
1.
Use a seismogram towork out the delay, in seconds, between the
arrival of the Pwaves and Swaves.
2.
Put this value on the vertical axis that represents the time (at the
Mazatlán station, 43) and extend it until the S-P line.
3.
Go down vertically to the horizontal axis to obtain the distance
corresponding to the delay (420 km in the example).
4.
Repeat theprocesswith theother two seismograms. In thisway you
will know the distance of the earthquake from each station.
5.
Usethegraphicscaleonthemaptoconvertthedistancestocentimetres.
6.
Copy themap on a sheet of paper. Draw a circumference around
each stationwith the same radius as the distance to the epicentre.
For this, use the graphic scale. The epicentre is locatedwhere the
circumferences overlap.
Procedure
Usingwhat you have studied in the unit, you can use a
seismogram to calculate the distance of an earthquake
and locate the epicentre.
0 10 20 30 40 50 60 70 80 90 100 110
TimedelaybetweenwavesPand S (s)
Mazatlán
Rosarito
Chihuahua
P
P
P
S
S
S
1.
A cyclist andamotorcyclist leave
the samepoint at the same time.
Calculate thedelaybetween their
arrival times.
2.
Whatrelation istherebetweenthe
previousexampleandPwavesandS
wavesrecordedontheseismogram?
3.
Whatrelationcanyoufindbetween
theS-Pdelayandtheamplitudeofthe
vibrationsontheseismogram?
4.
Whatcity is theepicentreof this
earthquake in?Explain inyourown
words theprocessyou followed.
5.
Whatwould the seismogramof a
station verynear theearthquake
be like?
a)
Once youhave chosen thedisaster, findoutwhenandwhere ithappened,
andwhat the consequenceswere for thepeople living in thearea.
b)
If you chooseanearthquake, indicate itsmagnitudeon theRichter scale,
itsmaximum intensity and its relationwith the lithospheric plates.
c)
If you choose a volcano, find out theVEI, the type of eruption and if it
produced pyroclastic flows, lahars or other phenomena.
1. Research
Youwillwriteanarticle topresent your results:
–
It should be at least two pages long and present the information you
have found in an organisedway
–
Write an introduction of approximately five lines that presents the
disaster and answers the five classical questions.
–
Then describe in detail the damage and its causes,and any information
about the geological aspects that you have learned in the unit.
2. Presentation of results
Follow these steps for your research:
Search for information
❚❚
First decidewhich disaster you are going to investigate.
For this you can:
• Focus on one that you remember because of the
serious consequencesorbecause it affected the area
where you live.
• Chooseonementioned in theunit.
• Doa searchon the Internetusing searchphrases like,
‘biggest earthquakes in history’ or ‘biggest volcanic
eruptions inhistory’.
❚❚
Keep in mind that the more recent the disaster, the
more information therewillbe.
❚❚
Consult specialised webpages and in the libraries of
digitalnewspapers.
Organise the information
❚❚
A newspaper article must answer these five classical
questions:what,where,when,how,andwhy.
❚❚
Adddrawings to theexplanationsabout thegeological
processes to make it easier for the readers to
understand.
❚❚
Donot forget to include in thearticleamap thatdetails the
locationof thecatastrophe.
Obtain conclusions and verification
❚❚
Check that each image you have downloaded has a
high enough resolution and corresponds to the subject.
❚❚
Check that you have chosen an interesting title that
gets theattentionof the readersand reflects the subject
correctly.
Procedure
❚
Answer the followingquestions to evaluate yourwork.
1.
Have I answered all the suggestedquestions?
2.
Have I paid attention to the presentation, spelling
andwriting?
3.
Have I included graphic information relating to the
event?
4.
Evaluateyour research taskglobally from1 to5,where
1 is insufficient and 5means you have accomplished
all theobjectives.
SELF-ASSESSMENT
Throughout history, there have been
numerous natural disasters. Some, like
the one in Pompey (in the photo) left
evidence of the terrible impact, buried
under innumerable layers of lava and ash. There are
evenfilms,somesciencefiction,aboutthesedestructive
processes.Now thatyouknowhow theyoccur,youwill
beable todoyour research task.
GEOLOGY_3_Unit 1 (9).indd 20-21
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19
1. Internalgeologicalprocesses
1
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Relief and its evolution
48.
What two types of crust are found on the Earth? In
yournotebook,write twodifferencesbetween them.
49.
Is relief unalterable or does it change over time?
Explainyouranswerandgiveexamples.
50.
In your notebook, name and define the main
featuresof the reliefof theocean floor.
51.
Explain how the plates contributed to the
formationofmountain chains.
Externaland internalgeologicalprocesses
52.
What different roles do internal and external
processesplaywith respect to relief?
53.
What are the different engines that drive internal
andexternalprocesses?
54.
Differentiate between the concepts of agent and
geologicalprocessandgivepracticalexamples.
55.
State three consequencesof themovementof the
lithosphericplates for relief.
56.
What are the convection currents that existbelow
the lithosphere? What role do they play with
respect to theplates?
57.
Explain the role thatgravityplays in the actionsof
internal andexternalagents.
58.
Calculate the temperature that would exist in the
centreof the Earthmaintaining thegeothermic slope
of30ºC/kmonthesurface.Doyouthinkthis ispossible?
Manifestationsof the Earth`s internal
energy
59.
In your notebook, define the following
concepts:
epicentre
,
crater
,
magma chamber
,
hypocentre
,
seismogram
.
60.
Lookat the two imagesof the sameearthquake.
a)
What are they called?Whatdo they represent?
b)
Identify,ononeof them, the two typesof internalwaves.
c)
Whichone is registeredcloser to theepicentre?Give two
reasons.
Seismic and volcanic risk
74.
Look at the table andput the risks associatedwith
volcanism in order of severity. Do you think that
famineswould cause somanydeaths today?
75.
Explain how the risk would vary in an area with
moreor lessdanger and vulnerability.
76.
Explain the influence of the relief of the land or
thewinds,on volcanic risk.
77.
Are the following phenomena related to
volcanic eruptions, earthquakes or both?
Lava
streams
,
ground movement
,
tsunami
,
lahar
,
ash
accumulation
.
78.
What measures would you take if you were
surprisedby a volcaniceruptionneara volcano?
79.
The image shows a
pyroclastic flow.What
are they composed
of and how do they
form? Why are they
dangerous?
80.
What is the difference between prediction and
prevention?
81.
Theearthquake inLorca, in2011,hadamagnitude
of 5.1 and the hypocenterwas located only 1 km
deep.Howdid this influence thedamage itcaused?
61.
Whichareasoftheplanethavethemostearthquakes
and volcanoes?
62.
Name three large lithospheric plates.What plate
does the Iberian Peninsula belong to? And the
Canary Islands?
63.
What are faults andwhat role do they play in the
originof earthquakes?
64.
What is theRingof Fire in the PacificOcean?
65.
What types ofmovement can exist between two
plates?Whathappens ineach case?
66.
Find outwhat two types of surfacewaves exist and
whatmovement theyproduceon theEarth’s surface.
67.
Copy this diagram in your notebook and label
where superficial and deep earthquakes and
volcanoes canbe found.
Volcanic activity and relief
68.
Whichmaterial ismore viscous andwhich ismore
fluid: jam or oil?What type of lava is associated
with eachof theseproperties?
69.
In your notebook, name the solid materials that
volcanoeseject, inorder from smallest to largest.
70.
MountOlympusonMars is25km
high and 600 km in diameter.
It is the biggest volcano in the
solar system. What type of
volcanodoyouthink it is?What
would the lavaejectedbe like?
71.
In your notebook, match each one of the
following characteristicswith a shield volcanoor a
stratovolcano:
a)
It ejects thick lava.
b)
Ithas a concaveprofile and is very steep.
c)
It ejectsfluid lava.
d)
It is formedmostlyof lava.
e)
Its eruptions arequite small.
72.
Find someexampleof roques in theCanary Islands
and explain theirorigin.
73.
Most of the Columbretes Islands, located off the
Castellón coast,are ring-shaped. Explainwhy.
82.
What should you do in the case of an earthquake
in the classroom?
83.
Can an earthquake have severalmagnitudes and
onlyone levelof intensity?Andviceversa?Explain.
Theday the sea swallowed the land
It was nearly eight o’clock in the morning on 26
December. The earth trembled four thousandmetres
deep in the Indian Ocean, 260 kilometres west of
the coast of Aceh, in Indonesia. Meanwhile, on the
paradisiacal coasts of Thailand, Indonesia, India, Sri
Lanka and the countries of south-east Asia, people
prepared to startanotherdayat thebeach.
Not even the most pessimistic person could have
thought that many people would not see the New
Year. Hours later, a chain of tidalwaves, provoked by
theenormousearthquake that reached9on theRichter
scale,wiped the idyllic islands from themap. Beaches
and townswhichwere submerged in a dense layer of
mud,waterand corpses.
ElMundo
,December 2004
(Translated andadapted)
a)
What internalgeologicalprocess is the textabout?
b)
What is thenameof thephenomenadescribed,apart
from tidalwave?
c)
What adjectivesdoes the authoruse to refer to the
coastalareasbefore the catastrophe?
d)
It has been said that a good part of the 200 000
deaths couldhavebeenavoided.How?
e)
What was the magnitude reached on the Richter
scale,mentioned in the text?
f)
Howwouldthenumberofvictimshadbeenaffected if
theearthquakehadoccuredatnightoratmidday?
READANDUNDERSTAND SCIENCE
CONSOLIDATION
0 10 20 30 40 50 60 70 80 90
0 10 20 30 40 50 60 70 80 90 100
250
150
0mm
150
250
250
150
0mm
150
250
Risk
Deaths
Risk
Deaths
Lava flows
1000 Tsunamis
44000
Ash andpyroclastic
fall
11000 Earthquakes related
to volcanic activity
100
Hot avalanches
55000 Gasesand acid rain 1200
Lahars (mudflows) 40000 Faminesand illnesses 110000
❚
Createyourown summaryof theunitusing the
Keyconcepts
.Addother important information.
❚
Copy the following diagram in your notebook and add themissing information to create a
conceptualmapof theunit.
❚
Create yourown scientificglossary. Include the following terms:
chimney
,
crater
,
earthquake
,
epicentre
,
focaldepth
,
geological agent
,
geological process
,
geological risk
,
geothermal gradient
,
hypocenter
,
intensity
,
lahar
,
landscape
,
lithosphericplates
,
ocean ridge
,
magnitude
,
pyroclasticmaterial
,
relief
,
seismicwave
,
shield volcano
,
stratovolcano
,
trench
,
tsunami
,
volcano.
You canaddanyother terms you consider important.
STUDY SKILLS
You can record your
summary and listen
to it asmany times
as you like to revise.
Relief
is conditionedby
Geologicalprocesses
are
cause
Geological agents
Internal
causedby
heat in theEarth’s interior
External
causedby
solarenergy
GEOLOGY_3_Unit 1 (9).indd 18-19
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PRESENTATION
In order to give you an overview of the unit, there’s a large picture
and some questions to stimulate previous knowledge. This will
help you relate the unit content to some aspects of your daily life,
and show you how the content can be applied to real life. We
recommend that you answer the questions throughout the unit.
There’s also a
final task
which we will prepare you for as you go
through the unit. The same task is also presented in digital format
in
Oxford Investigation.
The link near the picture will take you
to a short introductory video.
You have a
DUAL BOOK
:
a printed book and its electronic version,
which includes resources for you to use together with the unit. In
order to access the electronic version, use the code in the book
and follow the instructions. You will be able to work either online
or offline.
Digital icon:
This icon reminds you that there is a digital
version of your DUAL BOOK, Oxford Investigation. In this
version,youwill find reading comprehensionworksheets,animated
videos, videos, relevant web links and interactive versions of all the
course book activities.
CONTENT DEVELOPMENT
On these pages, there is an explanation of the material you are
going to study. The activities are categorised based on Bloom’s
taxonomy, in order to develop critical thinking skills. There
is a brief summary of the content
(key concepts)
at the end of each
lesson in the margin.
●
Differentiatebetween internaland
externalgeologicalprocessesand
identify theireffectson relief.
●
Understand theoriginof
earthquakes, theireffectsand the
areasof theplanetwhere theyare
mostcommon.
●
Understand themechanismsofa
volcaniceruptionand thecausesof
different typesoferuptions.
●
Evaluate seismicand volcanic risks
in theareawhere you live.
●
Evaluate the roleofpreventionand
prediction in reducingdamage
and thenumberof victims that
earthquakesand volcanoescause.
●
Carryouta research task.
1
YOUWILLLEARNTO…
INTERNAL
GEOLOGICAL
PROCESSES
Describe thephoto.What ishappening?
Can youdescribe the reliefof theoceanfloor?
TheTeide is thehighest summit inSpain.Whatnatural
processescaused it to rise?Whichprocessesare reducing it?
Roquesareoneof themost spectacular landforms in the
Canary Islands.Can youexplainhow rocksbecomeprojected
from theEarth’s surface?
Why is the riskofanearthquakemuchhigher in someareas
than inothers?
Do youknowwhat todo if there isanearthquake?
5
1. Internalgeologicalprocesses
Final
task
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Analysisofanaturaldisaster
InMay 2011, an earthquake with the magnitude of 5.1 on the
Richter scale hit the town of Lorca (Murcia).More than a century
before, in1884, an earthquake inArenasdelRey (Granada) almost
caused the totaldestructionof this town aswell as seriousdamage
in neighbouring towns.
Spain has a relatively low risk rate compared to other areas of
the planet,where this type of phenomena has taken hundreds of
thousands of lives.
In this unit youwill discovermore about the origin of earthquakes
and volcanoes, howwe can predict them or prevent their effects
and how they contribute to constructing the Earth’s relief.
At the end of the unit, youwill analyse one of these disasters that
you choose and you will write a news article in which you will
demonstratewhat you have learned.
Can you remember any natural disasters and how the images
affected you?
Can you explain the causes of this or other disasters?
GEOLOGY_3_Unit 1 (9).indd 4-5
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1. Internalgeologicalprocesses
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Analyse
2.
Ocean ridges are impressive oceanic landforms. Find outwhat they
areandhow they are formed.Writea summary.
3.
Find themeaning of these terms:
craton
,
continental shelf
,
trench
,
continental rift
.Write the definitions and give specific examples of
eachone.
4.
Mountain rangesare themost significant continental landforms.Why
is itpossible to findmarine fossils in the rocks?
5.
Investigateand explainwhat the sonar technique consistsof.
6.
What consequences would there be if the Earth had only type of
crust?
Key concepts
❚❚
The reliefof thecontinentsand
oceanshasdifferent features.
❚❚
Relief is continually subject to
both gradual and sudden
changes.
1.1.
Evolutionof relief
The age of the Earth ismeasured inmillions of years.During this time, there have
been continuousandenormous changes in the relief, thepositionof the continents
andoceans,and the climateand vegetation.Themost significant changesare those
that affect the size and the position of the continents. They changed from being
almostnon-existent tooccupyingalmosta thirdof theEarth’s surface.
150million years ago (Jurassicperiod)
500million years ago (Cambrianperiod)
Reconstructionof the Earthatdifferentmoments in thepast
Understand
7.
Look at the three photos above. Listen and saywhich process is
described.
8.
Explain inyourownwordsthedifferencebetweentheterms landscape
and relief.
9.
Whatwould the landscapearoundyoube likewithouthumanaction?
10.
Give at least two examples of gradual and sudden processes that
change the relief.
Analyse
11.
Discusswhat the Earthwill look like in one hundred thousand years.
Doyou think itwillbe the sameasnow?Explainyouranswerandgive
specific examples.
1.
RELIEFAND ITS EVOLUTION
Ourplanethas features thatmake itauniqueplanet inour solar system.Themost
significant feature is thepresenceofahydrosphereandanatmosphere.TheEarth’s
relief isalsounique.This ispartlydue to theexternalactionof thehydrosphereand
atmosphere on the surface, and also to internal activity resulting from the heat
stored
1
in the Earth’s interior. This internal activity builds and creates the features
of theEarth’s relief.
Themost significant and evident feature of the Earth’s relief is the presence of
continents
and
oceans
. This is due to the two different types of crusts: the
continentalcrust,which is thickerand lighterand thereforeabove theoceaniccrust,
which is thinner anddenser.As a result, the average elevationof the continents is
800m above sea level,but averagedepthof theoceans is3800m.
In the continents and oceans,we find themain features of relief as shown in the
diagram below.Many of these, such as themountain ranges, ocean ridges, or
trenchesdonotexistonanyotherplanet in the solar system.Remember thatuntil
the1960s,when theocean floorwas studiedbyusing sonar,weknewmoreabout
the surfaceof themoon than the reliefof theocean floor.
slip faults
rift
subduction
subduction
trench
island arc
ocean ridge
abyssalplain
continental shelf
mountain range
craton
continental
rift
trench
Main featuresof the Earth’s relief
Relief
is the change of elevation of the Earth’s surface, produced by a
combination of geographical landforms, such asmountains, valleys, plains,
or plateaus.
Landscape
is the combination of the relief, the vegetation that
covers it and the effectofhumanactivity.
The surfaceof theMoon
Understand
1.
What are the most
significant features of
lunar relief? How were
theyformed?Whyaren’t
theremanyonEarth?
Volcaniceruption
Cliffs
Dunes
1
stored
:
produced inside and
accumulated
The landscape, especially the vegetation, is very vulnerable to human action. Fires,
cutting down trees, urbanisation of land and construction of communication links
quickly transform the landscape,especially inmoredenselypopulatedareas.The relief
that surroundsus looks solidandunalterable
2
but italso changes.Thereare very slow
processesthatareunnoticeable inaperson’s lifetime,suchastheerosionofamountain
or themovementof thecontinents.Otherprocessesaresuddenandviolentandcause
bigchanges ina shortperiodof time, suchasvolcaniceruptionsorearthquakes.
2
unalterable
:
impossible tochange
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