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

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Figure 5.13: Seismic monitoring of volcanic activity.areas often have fertile soils and may be attractive to tourists, so that much building hastaken place on potentially hazardous volcanic slopes. <strong>The</strong> most effective way of reducingrisks in these areas is to monitor and prepare.Volcanoes can be monitored by a wide variety of methods. Nowadays, some volcanoesare routinely monitored remotely by satellites that can identify temperature changes,emission of sulfur dioxide or ash clouds, or small changes in shape of the surface of thevolcano. Meanwhile ground monitoring techniques that have been developed over manyyears include seismic monitoring (many eruptions have increased small earthquake activitybefore eruption and some seismic traces are characteristic of lava movement at depth);monitoring of the shape of the volcano (by tiltmeters, that detect changes in the slopesof surfaces); and by measuring the changes in altitude and distance across key parts ofthe volcano, to spot the development of volcanic bulges before eruptions. Try makingyour own tiltmeter from, ‘When will it blow?: predicting eruptions’ at http://www.earthlearningidea.com. On many volcanoes the emission of volcanic gases is monitored119
Figure 5.14: A GPS (global satellite positioning) remote volcano monitoring station,monitoring deformation of the slopes of a volcano.for any changes in gas composition that may occur before eruption, whilst small scalechanges in gravity and magnetism may also be used to predict eruptions. Unfortunately,all the equipment needed for thorough volcano monitoring is very expensive, so that,whilst many volcanoes in the USA are closely monitored, many in the developing worldare not. Eruption risk to populations is much higher in volcanic regions that have lesseffective monitoring systems.Scientists have been investigating earthquake prediction for many years and have shownthat, while it is impossible to predict earthquakes (the exact time and place where theywill occur) it may be possible to forecast earthquakes, suggesting the probability that anearthquake will occur at a given place at a given time. <strong>The</strong>se forecasts have been basedon a number of methods including:• seismic gaps: when faults are under plate tectonic pressure, some parts of faultsslip gently, whilst others are ‘locked’. <strong>The</strong> locked parts are seismic gaps, whereearthquakes have been recorded on either side, but not in the middle; the next bigearthquake is most likely in this seismic gap area. Figure 5.15 shows how the groundsurface moved in the Izmit earthquake in Turkey in 1999. Other major earthquakeshave happened along the fault to the east, so the next large earthquake is likely tobe in the seismic gap to the <strong>we</strong>st; this happens to be beneath the city of Istanbul.• foreshocks: many major earthquakes have smaller foreshocks beforehand, ho<strong>we</strong>ver,many small foreshock-like earthquakes can occur along a fault without a majorearthquake following them.120
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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
Page 83 and 84: 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
Page 99 and 100: Figure 3.15: The S
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
Page 111 and 112: planet extended th
Page 113 and 114: Figure 4.1: William Smith’s geolo
Page 115 and 116: Millionsof yearsago (Ma)01000Some M
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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: isk to humans. The
Page 137 and 138: None of these methods has yet prove
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
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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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The planet we live on: The beginnings of the Earth Sciences

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