The Mechanics of Earthquakes and Faulting

505 Pages·2002·25.14 MB·English

by  Scholz C.H.

TheMechanicsofEarthquakesandFaulting
2ndEdition
Ourunderstandingofearthquakesandfaultingprocesseshasdeveloped
significantlysincepublicationofthefirsteditionofthisbookin1990.Thisrevised
editionhasthereforebeenthoroughlyup-datedwhilstmaintainingand
developingthetwomajorthemesofthefirstedition.
Thefirstofthesethemesistheintimateconnectionbetweenfaultand
earthquakemechanics,includingfaultscalinglaws,thenatureoffault
populations,andhowtheseresultfromtheprocessesoffaultgrowthand
interaction.Thishasleadtoafullerappreciationofhowfaultingandearthquakes
areactuallydifferenttimescalemanifestationsofthesamedynamicalsystem.The
secondmajorthemeisthecentralroleoftherate-statefrictionlawsinearthquake
mechanics.Itisnowunderstoodthatthesefrictionlawsnotonlygovernthe
earthquakeinstabilityitself,butalsoresultinagamutofotherearthquake
phenomenaincludingseismiccouplinganddecoupling,pre-andpost-seismic
deformation,earthquaketriggering,andtherelativeinsensitivityofearthquaketo
transientssuchasearthtides.Thusfrictionlawsprovideaunifyingframework
withinwhichawiderangeoffaultingphenomenacanbeinterpreted.
Withtheinclusionoftwochapterswhichexplainbrittlefractureandrock
frictionfromfirstprinciples,thisbookiswrittenatalevelwhichwillappealto
scientistsfromavarietyofdisciplinesforwhomacompleteunderstandingof
faultingandearthquakesistheultimategoal.Graduatestudentsandresearch
scientistsinthefieldsofseismology,physics,geology,geodesy,androckmechanics
willgreatlybenefitfromthisbook.
ChristopherScholzexperiencedhisfirstearthquakeinCaliforniaattheageof
nineandhasbeenaskingquestionsaboutfaultingandearthquakeseversince.He
isnowProfessorofEarthScienceandAppliedMathematicsattheLamont-Doherty
EarthObservatory,ColumbiaUniversity,whereheuseslaboratoryexperiments,
theory,andfield-basedtechniquestostudybrittledeformationprocessesthat
occurintheoutermostlayeroftheEarth.Inadditiontoover160papersinthe
primaryliterature,ProfessorScholzisalsotheauthorofFieldwork:ageologist’s
memoiroftheKalahari(1997)andcoeditorofFractalsinGeophysics(1989).
AphotographbyG.K.Gilbertofthesurfaceruptureproducedbythe1906San
Franciscoearthquake.(PhotocourtesyoftheUSGeologicalSurvey.)
The Mechanics of
Earthquakes and Faulting
2nd edition
ChristopherH.Scholz
Lamont–DohertyGeologicalObservatoryand
DepartmentofEarthandEnvironmentalSciences,
ColumbiaUniversity
cambridge university press
Cambridge,NewYork,Melbourne,Madrid,CapeTown,Singapore,Sa ~oPaulo,
Delhi,Tokyo,MexicoCity
CambridgeUniversityPress
TheEdinburghBuilding,CambridgeCB28RU,UK
PublishedintheUnitedStatesofAmericabyCambridgeUniversityPress,NewYork
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Informationonthistitle:www.cambridge.org/9780521652230
©CambridgeUniversityPress2002
Thispublicationisincopyright.Subjecttostatutoryexception
andtotheprovisionsofrelevantcollectivelicensingagreements,
noreproductionofanypartmaytakeplacewithout
thewrittenpermissionofCambridgeUniversityPress.
Firstpublished1990
Firstpaperbackedition1990
Reprinted1992,1994,1997,2000
Secondedition2002
7thprinting2012
PrintedatMPGBooksGroup,UK
AcataloguerecordforthispublicationisavailablefromtheBritishLibrary
LibraryofCongressCataloguinginPublicationdata
Scholz,C.H.(ChristopherH.)
Themechanicsofearthquakesandfaulting/ChristopherH.Scholz.–2nded.
p.cm.
Includesbibliographicalreferencesandindex.
ISBN0-521-65223-5(hardback)–ISBN0-521-65540-4(paperback)
1.Seismology.2.Faults(Geology) I.Title.
QE534.2.S372002
551.22–dc21 2001043297
ISBN978-0-521-65223-0Hardback
ISBN978-0-521-65540-8Paperback
CambridgeUniversityPresshasnoresponsibilityforthepersistenceoraccuracy
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...andthentherewouldnotbefrictionanymore,andthesoundwouldcease,andthe
dancerswouldstop...
LeonardodaVinci
FromanotebookdatedSeptember,1508
MacCurdy, E. 1958. The Notebooks of Leonardo da Vinci, p. 282, New York: George
Braziller.

Contents
Prefacetothefirstedition xi
Prefacetothesecondedition xv
Acknowledgments xvii
Listofsymbols xx
1 Brittlefractureofrock
1.1 Theoreticalconcepts 1
1.1.1 Historical 1
1.1.2 Griffiththeory 4
1.1.3 Fracturemechanics 9
1.1.4 Crackmodels 13
1.1.5 Macroscopicfracturecriteria 17
1.2 Experimentalstudiesofrockstrength 21
1.2.1 Macroscopicstrength 22
1.2.2 Fractureenergies 28
1.2.3 Discussionoffracturecriteriainthelightofexperimentalresults 31
1.2.4 Effectofscaleonstrength 35
1.3 Porefluideffectsonfracture 37
1.3.1 Lawsofeffectivestress 37
1.3.2 Environmentaleffectsonstrength 39
1.4 Thebrittle–plastictransition 43
1.4.1 Generalprinciples 44
1.4.2 Thetransitioninducedbypressure 46
1.4.3 Thetransitioninducedbytemperature 48
1.4.4 Extrapolationtogeologicalconditions 50
2 Rockfriction
2.1 Theoreticalconcepts 53
2.1.1 Historical 53
2.1.2 Theadhesiontheoryoffriction 55
2.1.3 Elasticcontacttheoryoffriction 57
2.1.4 Otherfrictionalinteractions 63
vii
viii Contents
2.2 Experimentalobservationsoffriction 66
2.2.1 Generalobservations 67
2.2.2 Effectsofothervariablesonfriction 68
2.2.3 Wear 77
2.3 Stickslipandstablesliding 81
2.3.1 Introduction 81
2.3.2 Rateeffectsonfriction:therateandstatevariablefrictionlaws 83
2.3.3 Frictionalstabilityregimes 87
2.3.4 Dynamicsofstickslip 94
2.4 Frictionundergeologicalconditions 97
3 Mechanicsoffaulting
3.1 Mechanicalframework 101
3.1.1 Anderson’stheoryoffaulting 101
3.1.2 Hubbert–Rubeytheoryofoverthrustfaulting 104
3.1.3 Stressinthecrust,faultreactivation,andfriction 107
3.2 Theformationandgrowthoffaults 110
3.2.1 Theproblemoffaultformation 110
3.2.2 Growthanddevelopmentoffaults 115
3.2.3 Faultinteractionsandfaultpopulations 126
3.3 Faultrocksandstructures 135
3.3.1 Faultrocksanddeformationmechanisms 136
3.3.2 Fabricsandsurfaces 141
3.4 Strengthandrheologyoffaults 145
3.4.1 Asynopticshearzonemodel 146
3.4.2 Deepductileshearzones:thedownwardcontinuationoffaults 154
3.4.3 Thermomechanicaleffectsoffaulting 155
3.4.4 Thedebateonthestrengthofcrustalfaultzones 158
3.5 Faultmorphologyandmechanicaleffectsofheterogeneity 168
3.5.1 Faulttopographyandmorphology 168
3.5.2 Mechanicaleffectsoffaultirregularities 173
4 Mechanicsofearthquakes
4.1 Historicaldevelopment 179
4.2 Theoreticalbackground 182
4.2.1 Thedynamicenergybalance 182
4.2.2 Dynamicshearcrackpropagation 185
4.2.3 Simpleapplicationstoearthquakerupture 195
4.3 Earthquakephenomenology 198
4.3.1 Quantificationofearthquakes 198
4.3.2 Earthquakescalingrelations 202
4.4 Observationsofearthquakes 211
4.4.1 Casestudies 211
4.4.2 Earthquakesequences 224
4.4.3 Compoundearthquakes:Clusteringandmigration 229
Contents ix
4.5 Mechanicsofearthquakeinteractions 234
4.5.1 Coulombstressloading 234
4.5.2 Mechanismsforthetimedelay 237
5 Theseismiccycle
5.1 Historical 244
5.2 Thecrustaldeformationcycle 247
5.2.1 Geodeticobservationsofstrainaccumulation 248
5.2.2 Modelsofstrainaccumulation 254
5.2.3 Postseismicphenomena 259
5.3 Theearthquakecycle 265
5.3.1 Earthquakerecurrence 265
5.3.2 Geologicalobservationsofrecurrencetimes 273
5.3.3 Recurrenceestimationwithinsufficientdata 283
5.3.4 Seismicitychangesduringtheloadingcycle 287
5.3.5 Thequestionofearthquakeperiodicity 291
5.4 Earthquakerecurrencemodels 294
6 Seismotectonics
6.1 Introduction 300
6.2 Seismotectonicanalysis 303
6.2.1 Qualitativeanalysis 303
6.2.2 Quantitativeanalysis 306
6.3 Comparativeseismotectonics 309
6.3.1 Subductionzoneseismicity 309
6.3.2 Oceanicearthquakes 318
6.3.3 Continentalextensionalregimes 323
6.3.4 Intraplateearthquakes 326
6.3.5 Mechanismofdeepearthquakes 329
6.3.6 Slowandtsunamigenicearthquakes 331
6.4 Therelativeroleofseismicandaseismicfaulting 333
6.4.1 Aseismicslip 334
6.4.2 Seismiccouplingofsubductionzones 337
6.5 Inducedseismicity 341
6.5.1 Someexamples 342
6.5.2 Mechanismsofreservoir-inducedseismicity 344
6.5.3 Mining-inducedseismicity 348
6.5.4 Inducedseismicityasastressgauge 350
7 Earthquakepredictionandhazardanalysis
7.1 Introduction 351
7.1.1 Historical 351
7.1.2 Typesofearthquakeprediction 352
7.1.3 Isearthquakepredictionpossible? 356