The planet we live on: The beginnings of the Earth Sciences

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Figure 5.15: An interferogram of the Izmit earthquake, Turkey, 1999, produced by comparingsatellite data from before and after the earthquake. Most movement of the groundsurface occurred where the colour bands are closest together and this shows the positionof the fault very clearly.• ground deformation: deformation of the ground near a fault, measured using stressgauges, tiltmeters or by surveying, may provide signs of a future earthquake.• groundwater variations: as pressure increases in the rocks around a fault, cracks mayopen or close causing the level of the water table in <strong>we</strong>lls or boreholes to change,suggesting a future earthquake.• radon gas: the cracking of rocks before an earthquake may release radon gas intothe groundwater, which can be detected.• geomagnetic and geoelectric changes: changes in both local magnetism and localelectrical resistance have been recorded just before an earthquake struck.• earthquake lights: there have been reports of ‘earthquake lights’ before earthquakes,flashes of red and blue light in the sky that may be caused by quartz crystalsfracturing under stress.• animal behaviour: there have been accounts of some animals like dogs and catsbehaving strangely before earthquakes, but it has not been possible so far to usethis in effective earthquake forecasting.121
None of these methods has yet proved to be scientifically successful in reliably forecastingearthquakes. Meanwhile, scientists have to be very careful not to forecast an earthquakethat doesn’t happen, since an inaccurate forecast can be very costly and the populationis less likely to take notice of future forecasts. <strong>The</strong> work of seeking reliable earthquakeforecastingtechniques is likely to continue for many years to come.Landslides can be fast or slow-moving. <strong>The</strong>re is no time to monitor fast-moving events, butlandslides that creep slowly and threaten buildings or other constructions such as roads,can be monitored by instruments to detect movement, ground vibration, groundwaterchanges, or rainfall. Ho<strong>we</strong>ver, this is expensive, and is only usually possible in <strong>we</strong>lldevelopedcountries.A range of techniques is available to reduce the effects of creeping landslides, includingimproving drainage, planting vegetation to bind the material with roots and remove water,and anchoring the toe of slips with heavy masses of material or stone-filled gabion baskets.Rockfall hazards in steeper areas can also be reduced by using rock bolts to tie downlooser sections, by covering steep surfaces with mesh geotextiles or concrete blankets(shotcrete) and by building fences and ditches to catch debris. Again, these remediationtechniques are usually only possible in <strong>we</strong>ll-developed countries.<strong>The</strong> final stage of tackling geohazard risk, after assessing geohazard impact, controllingbuilding construction, and using prediction/monitoring methods, is to develop plans toprotect the population during and after an event. Such plans will differ, depending on thetype of event and its likely scale. Ho<strong>we</strong>ver, most plans have in common: the training of theemergency services, the education of the population on what to do and when, the use ofearly warning systems where possible, the development of evacuation plans, procedures tomaintain essential services, and strategies to call in extra help and resources if necessary.See the ‘Surviving an earthquake’ activity at http://www.earthlearningidea.com.5.2 Human impacts on climate changeMedia reports often link all sorts of natural disasters to climate change but, althoughclimate change will have long term effects on the Earth, it is not directly responsible forshort term changes like those in the <strong>we</strong>ather or sudden geohazard events.Nevertheless, as shown in Section 3.3 of this book, climate change could have dramaticeffects in the future. Global warming could cause marked temperature rises and increasesin drought in some parts of the Earth, linked surprisingly to cooling in others. Global climatebelts would tend to move towards the poles and the world’s <strong>we</strong>ather patterns wouldprobably become more stormy. If the warming caused major melting of the continentalice sheets (on Greenland and Antarctica), global sea levels would rise significantly. Meanwhilethe water in the warming oceans would also expand, causing many low-lying areas,including many of the world’s major cities, to be prone to large-scale flooding duringstorms.For these reasons, many scientists and an increasing number of politicians and other influentialpeople across the world are arguing that the human population should do all122
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Basic Books in ScienceBook 6<strong
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BASIC BOOKS IN SCIENCE- a Series of
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BASIC BOOKS IN SCIENCE- a Series of
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Looking ahead - If you came across
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3.2 Plate tectonics (20th Century)
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1.30 Coal seams in an opencast coal
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3.4 Alfred Wegener, the polar explo
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5.14 A GPS remote volcano monitorin
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Figure 1.2:minerals.A sandstone roc
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Even diamond can have different col
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Figure 1.8: A red garnet crystal in
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Figure 1.12: Crystals of minerals i
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Hematite, Fe 2 O 3 - earthy red, me
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Figure 1.17: Sedimentary rocks show
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Figure 1.20: A close up view of a p
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Figure 1.26: Ancient wave ripple ma
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Figure 1.30: Coal seams in an openc
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Figure 1.32: Close up view of a pie
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Figure 1.35: A fossil colonial cora
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Figure 1.38: Fossil ammonites, indi
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Figure 1.39: ‘Massive’ igneous
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Figure 1.41: A close up view of a p
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Figure 1.44: A basalt flow that coo
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Figure 1.47: Deposit of volcanic as
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Figure 1.49: An old slate quarry, s
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Figure 1.51: Slate, a low-grade met
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Figure 1.53: Schist, a medium-grade
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Figure 1.56: Metaquartzite, produce
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Figure 1.58: A region of folded roc
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Figure 1.61: A normal fault. This s
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Figure 1.64: An unconformity. Older
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proper geological maps. Fossils hav
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Cephalopods are not extinct, but th
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Figure 1.68: A shelled cephalopod f
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You can try the rock sequencing pri
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Chapter 2Reading landscapes: how la
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Figure 2.3: Rock fragments loosened
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Figure 2.6: The jo
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Figure 2.10: The m
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are forming them. Similarly the sha
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Figure 2.19: This photo was taken f
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Figure 2.25: Dinosaur tracks conser
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Page 87 and 88: found evidence that the Earth was a
Page 89 and 90: Figure 3.3: James Hutton, the ‘Fo
Page 91 and 92: Figure 3.5: A page of Wegener’s 1
Page 93 and 94: Figure 3.7: The st
Page 95 and 96: Figure 3.10: The r
Page 97 and 98: Figure 3.13: The m
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Page 101 and 102: Figure 3.19: An ocean versus contin
Page 103 and 104: Figure 3.23: Map of the major tecto
Page 105 and 106: Figure 3.26: Global temperature cha
Page 107 and 108: Figure 3.29: A computer generated p
Page 109 and 110: Figure 3.31: The
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Page 113 and 114: Figure 4.1: William Smith’s geolo
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Page 119 and 120: Figure 4.9: The ch
Page 121 and 122: Figure 4.12: The 4
Page 123 and 124: Millionsof years Some Major Earth E
Page 125 and 126: Figure 5.2: Strike-slip movement (r
Page 127 and 128: Figure 5.4: The So
Page 129 and 130: Figure 5.6: An ash eruption rising
Page 131 and 132: Figure 5.10: A hazard zone map of t
Page 133 and 134: isk to humans. The
Page 135: Figure 5.14: A GPS (global satellit
Page 139 and 140: Figure 5.17: A windfarm in Ireland.
Page 141 and 142: Figure 5.19: A beautifully preserve
Page 143 and 144: Another ‘missing link’ find has
Page 145 and 146: Figure 5.22: A dinosaur reconstruct
Page 147 and 148: Figure 5.25: A working aggregate-pr
Page 149 and 150: Figure 5.26: The E
Page 151 and 152: Chapter 6Understanding what geologi
Page 153 and 154: Figure 6.2: A drilling rig used for
Page 155 and 156: When an oil/gas field has been foun
Page 157 and 158: Figure 6.6: Groundwater flowing out
Page 159 and 160: Dam disaster in Italy, when the wav
Page 161 and 162: Figure 6.10: A slab foundation, bui
Page 163 and 164: An example of this is investigation
Page 165 and 166: GlossaryAbsolute age The</s
Page 167 and 168: Carbon capture The
Page 169 and 170: Crustal shortening This results of
Page 171 and 172: Evaporite deposits (or evaporites)
Page 173 and 174: Geophysical survey Using the method
Page 175 and 176: “Integrated waste management” <
Page 177 and 178: Metamorphism The r
Page 179 and 180: Pore spaces (or pores) Gaps bet<str
Page 181 and 182: Saltation Sediment movement by flui
Page 183 and 184: Suspension Sediment movement by flu
Page 185 and 186: AcknowledgementsPermission to repri
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Figure 2.3 A scree slope. Photo ID:
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Figure 1.15a Hematite.Figure 1.15b
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Figure 1.28 Dune cross bedding in s
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Figure 3.18 An island arc volcano,
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Figure 5.21 Excavations at the dino
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