Faults, stresses and mechanics of the upper crust: a ...merco220.free.fr/pdf/lacombe-bsgfintro-2013.pdf · ley fault in eastern Taiwan by means of geodetic surveys and creep-meter

An introduction to the special issue of the Bulletin de la Société géologique de France

Faults, stresses and mechanics of the upper crust:a tribute to Jacques Angelier

Guest editors: OLIVIER LACOMBE1 and FRANÇOISE BERGERAT2

Keywords. – Faults, Fractures, Brittle tectonics, Contemporary stresses, Active deformation, Paleostresses, Inversion of fault-slipdata, Crustal mechanics

IN MEMORIAM: JACQUES ANGELIER (1947-2010)

Jacques Angelier was born 2 March 1947 in Alès, France.He passed away on 31 January 2010. Jacques was a studentat ’Ecole Normale Supérieure’ of Saint-Cloud from 1966 to1970. He obtained his PhD in 1970 and his DSc in 1979.From 1970-71 Jacques was assistant lecturer at the Univer-sity Pierre & Marie Curie in Paris (Paris VI), and from1971-76 assistant lecturer at the University of Orléans. Fol-lowing his stay in Orléans, Jacques returned to UniversityPierre & Marie Curie in 1976 as an assistant professor and,from 1981, as a full professor. Jacques worked in Paris until2003, then moved to the Oceanological Observatory of Vil-lefranche-sur-Mer, also a part of University Pierre & MarieCurie.

The main research activities of Jacques Angelier werein the fields of structural geology and geodynamics, withfocus on brittle deformation. He was a leader in analysingcrustal stresses, that is, in developing methods to unders-tand the various stress fields to which the Earth’s crust hasbeen subjected through time. The basic techniques are in-version of fault-slip data from minor fault sets measured inthe field and of focal mechanisms (fault-plane solutions) ofearthquakes in a given area to calculate the state of stress.

Inversion of fault data is primarily used to infer theso-called “paleo-stresses”, that is, the state of stress thatexisted in the past at the time of fault slips. This method re-lies much on measurements and interpretation of striationson fault planes in the field. Focal mechanisms of earthqua-kes are used to infer current stresses in active fault zones.Jacques developed computer programs to calculate thestress tensors from these various types of data.

Jacques Angelier applied his methods to carry out re-gional and local brittle-tectonic studies in many countriesand regions. These include North Africa, Greece, Turkey,Mexico, USA, Japan, Korea, Russia, Ukraine, Iran, Canada,Greenland, Taiwan, Iceland and, of course, France.

Since the late 1980’s his research focused increasinglyon active deformation. This work enabled him to combinefield studies of brittle deformation with the analysis of

earthquakes, the focus of the latter being on seismotecto-nics and associated current stress fields. The main targets ofhis seismotectonic studies were the divergent plate bounda-ry of Iceland and the convergent plate boundary of Taiwan.

The great scientific legacy of Jacques Angelier, his im-pact on structural geology, in particular on the study ofbrittle deformation and crustal stresses, has been of first im-portance and will continue to be so for many years to come(photos 1 to 7).

INTRODUCTION TO THE SPECIAL ISSUE

It is of course almost impossible to make a complete state-of-the-art on crustal mechanics, and even to summarize allthe major steps that led to our present knowledge on this to-pic. As an introduction to the special issue, we have chosento focus on 3 aspects Jacques Angelier has worked on du-ring his carrier, and to recall what we think to have been no-ticeable steps, among many others...

State of stress in the earth crust

The natural stress field which exists in a rock mass is genera-ted by numerous mechanisms, such as gravitational loading,thermal changes, pore fluid diffusion, elevation differences,and last but not least, tectonics. The motivation to characte-rize the distribution of stresses in the crust arises from (1)applied geological purposes such as geological hazards(earthquakes, landslides), engineering activities (e.g., stabi-lity and safety of underground workings and boreholes) andresource exploration, but also from (2) fundamental geolo-gical purposes, such as understanding the mechanical beha-viour of geological materials and deciphering tectonicmechanisms at different scales (from the crystal to the plate).

Because (i) the exact geological history of rock massescannot be known precisely, (ii) the constitutive equationsdescribing the mechanical behavior of rocks remain ap-proximate, and (iii) the detailed structure of a rock masscannot be determined exactly, it is impossible to evaluate bystraight computation the natural stress field. For this reason,

Bull. Soc. géol. France, 2013, t. 184, no 4-5, pp. 291-297

Bull. Soc. géol. Fr., 2013, no 4-5

1. Professor at the Institut des Sciences de la Terre de Paris – ISTeP, Université Pierre et Marie Curie2. Research Director at the Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de la Terre de Paris – ISTeP, Université Pierre etMarie Curie

several techniques have been developed to try to measure orto reconstruct it. Among them, Jacques Angelier has beenone of the pioneers in the analysis of the orientation of theslip motions on faults determined either from the observa-tion of slickensides on ancient minor faults or from the fo-cal mechanism of the seismic events. Following first workson the topic [e.g., Carey and Brunier, 1974; Angelier, 1975,1984; Etchecopar et al., 1981], numerous techniques offault-slip data inversion for regional stress have been set outand are available for the community [see review paper byCélérier et al., 2012]. The use of fault slip parameters du-ring earthquakes and of earthquake focal mechanisms hasalso been a major stepforward for the understanding of thecontemporary state of stress [e.g., Byerly and Stauder,1957; Aki, 1968; McKenzie, 1969]. Together with othertechniques of in situ determination of the state of stress [seereview paper by Schmitt et al., 2012], these techniques haveprovided a large dataset on modern stresses which has beensynthetized in the form of two “World Stress Maps” [Zo-back et al., 1992; Heidbach et al., 2010], providing new in-sights into the dominant stress sources at different scales inthe lithosphere. To what extent paleostresses can becompared to modern stresses in terms of physical andgeological meaning still remains a matter of debate [seediscussion paper by Lacombe, 2012].

Fracture and fault mechanics

Fractures and faults are amongst the main features of thedeforming upper crust. They have been used for a long timeas reliable records of larger scale tectonics [e.g., Mattauerand Mercier, 1980] and understanding their initiation hasbeen (and is still) the purpose of many works over at leastthe last two centuries [e.g., Pollard and Aydin, 1988]. Jac-ques Angelier was interested in this topic: although he focu-sed more on geometrical and tectonic aspects than on truemechanical aspects, he for instance investigated effectivetension-shear fractures relationships, especially in extensio-nal settings (Suez, Iceland).

Early concepts on the mechanics of fracturing and faul-ting indeed date back to the 18e [e.g., Amonton, 1699; Cou-lomb, 1776; Daubrée, 1879; Mohr, 1900; Anderson, 1905;Griffith, 1924]. Coulomb [1776] developed his failure crite-rion by assuming that slip along any internal plane within amaterial was impeded by both cohesion and an internal fric-tion, and showed that failure/yield strength is pressure sen-sitive. Griffith [1924] addressed the problem of quasi brittlefracture/rupture based on the so-called Griffith energy ba-lance criterion that defines the stability condition of thepreexisting crack the propagation of which leads to rupture.An alternative view of the failure of materials considersfracture/rupture as resulting from a constitutive (or mate-rial) instability, which leads to the deformation bifurcationand to the formation of localization bands [e.g., Rice,1973]. As soon as in 1905, Anderson proposed, on the basisof experimentally deformed intact rocks, that the directionsof the principal stresses can be determined from a set ofconjugate faults. Frictional sliding along a preexisting planeof weakness in an otherwise homogeneous material was alsoinvestigated and was shown to be possibly modeled by aMohr-Coulomb criterion [e.g., Jaeger, 1959, 1960; Sibson,1985]. Byerlee [1978] demonstrated also on the basis of la-boratory tests that the sensitivity of strength to pressure is

constant for nearly all kinds of pre-cut rocks, thus openingthe way to the extension of his criterion to the pre-fracturedbrittle upper crust (the so-called Byerlee’s rule). Among recentways of fracture mechanics studies is the consideration ofthe entropy evolution of rock-fracture networks which mayprovide a basis for a better understanding of the energy in-put needed for fracture propagation and associated strainduring earthquakes or volcanic eruptions.

At a larger scale, fault zones control a wide range ofcrustal processes. Although they occupy only a small vo-lume of the crust, fault zones have a controlling influenceon the crust’s mechanical as well as fluid flow properties[see review paper by Faulkner et al., 2010]. Crustal stressmagnitudes at shallow crustal levels appear generally to belimited, and even controlled, by the frictional strength onwell-oriented faults (state of failure equilibrium). Such cri-tically stressed faults maintain high fluid permeability,hence hydrostatic fluid pressure, within the upper seismo-genic crust [Townend and Zoback, 2000]. Expected newdevelopments concern the better characterization of crus-tal-scale fault zones in terms of internal structure andfluid-rock interactions, localization of shear strain as wellas consideration of a realistic (e.g., elasto-plastic) rheologyto describe their long-term behavior.

Active tectonics, seismic rupture and fault dynamics

Jacques Angelier also addressed the problem of theshort-term behavior of active faults (locked vs creeping),for instance by studying the seismogenic Longitudinal Val-ley fault in eastern Taiwan by means of geodetic surveysand creep-meter analyses. He also addressed the kinematicsof active normal and strike-slip faults in Iceland.

Significant steps toward a better characterization ofshort-term crustal deformation related to faulting involvedthe use of interferometry [e.g., Massonet et al., 1993] andgeodetic survey (GPS) [see review paper by Segall and Da-vis, 1997]. GPS surveys allowed estimates of the size oflocked zones along faults as well as identification of thelack of slip in zones of seismic gap and the record of aseis-mic slips in subduction zones [e.g., Dragert et al., 2001],which are often associated with non-volcanic tremors recor-ded by seismological networks. Another input of GPS inseismology is the ability to record low frequency groundmotions.

Recent works also revealed the complexity of the seis-mic source and of the surface slip of major subduction ear-thquakes (e.g., patches characterized by velocity weakeningthus favoring seismogenic slip surrounded by zones in velo-city strengthening favoring aseismic slip during post- andinterseismic periods), the link between fault slip distribu-tion and fault roughness, the possible occurrence of super-shear seismic rupture and the recent identification of pre-earthquake tremors [e.g., Bouchon et al., 2008, 2011].Recent ways of investigation concern ionospheric seismo-logy and development of a spatial seismometer.

CONTENT OF THE VOLUME

This thematic issue gathers some of the contributions thatwere presented in the meeting “Faults: Why? Where?How?” held in the University Pierre et Marie Curie in No-vember 2011. This meeting was organized under the patro-

292 LACOMBE O. and BERGERAT F.

Bull. Soc. géol. Fr., 2013, no 4-5

nage of the French Academy of Sciences, the Pierre &Marie Curie University (UPMC) and the French GeologicalSociety, with the financial and logistic support of the Tai-wan National Science Council, GeoAzur (Nice) and ISTeP(Paris) geological departments, the Pierre & Marie CurieUniversity (UPMC), the international Laboratory ADEPTand TOTAL (photos 8 and 9)

This meeting provided the opportunity to re-assess ourknowledge on faults, from a regional point of view as wellas in terms of their geometrical, kinematical and mechani-cal analyses. Many contributors of the present issue are hisformer students (belonging to his school of “brittle tecto-nics and paleostress analysis”), colleagues and friends fromTaiwan, Iceland, Korea, Russia, UK and France. The con-tributions reflect a large part of the scientific legacy of JacquesAngelier: the topics of the articles range from primarilyfield-based tectonic studies to primarily theoretical studiesof crustal stresses and paleostresses, as well as on crustalmechanics and rheology.

The volume is divided into five chapters.

Stresses and paleostresses in the earth crust (1): methods

Lisle [2013] addresses the common assumption in fault-slipdata inversion for stress that slip on faults occurs in the di-rection of maximum resolved shear stress (Wallace-Bott hy-pothesis) by examining different situations in relation to theappropriateness of this assumption. He recommends cautionwith slip data taken from highly curved faults, corrugatedfaults, lineated portions of stylolitic surfaces, fault systemswith bends and flexural slip folds and points out that the as-sumption may not be valid in a strict sense for reasons ofstress heterogeneity, fault interactions and the fault’sstrength anisotropy, although this difficulty can possibly becircumvented by collecting a sufficient amount of fault-slipdata.

The article by Etchecopar et al. [2013] deals with boreholeimages for assessing present day stresses. A new processingand filtering method is proposed for identifying stress-indu-ced features and measuring precisely their geometry, andexamples are given in Algerian reservoirs: Timimoun, HassiMessaoud. The paper thus focuses on the morphology offractures observed and on critical analysis of the images.The combination of observations in multiple deviation si-tuations may lead to a clear stress state definition. Thus,this article presents a great practical interest: once the stresstensor parameters are clearly identified, it becomes possibleto predict borehole or perforation stability for any welldeviations.

Maury et al. [2013] discuss the commonly-used methodsfor inverting earthquake focal mechanisms for stress orien-tation, especially the physical assumptions and the error de-terminations, and finally propose an extension for one ofthe methods. The authors apply the fourth methods for eva-luating the stress field in the upper Rhinegraben, based onthe Sierentz earthquake (1980) data recorded by a tempora-ry network. They demonstrate that, depending on the me-thods used, differences in principal stress directions mayreach up to 28o and that values of the R factor, characteri-zing relative differences between principal stress magnitu-des, range between 0.3 and 0.7. They conclude on the lackof resolution for the evaluation of the stress field at depth

and on the proper attention, which has to be given to theevent independence hypothesis.

In their paper, Rebetsky and Tatevossian [2013] addresssome problems of earthquake source mechanics by repor-ting results of stress state reconstruction based on the me-thod of cataclastic analysis of discontinuous dislocations insome seismotectonic active regions. Using the Sumatra, To-kachi-oki and Chile strong earthquakes as case studies, theyemphasize common features of the stress state in areas ofpreparation of strong earthquakes, especially that the distri-bution of the effective isotropic pressure and of the maxi-mal shear stress in areas of earthquake source preparation isheterogeneous and that the main part of the source is alwaysassociated to crustal domains under low effective confiningpressure. It is further demonstrated that the rupture usuallypropagates from the region of high stress gradients towardcrustal domains characterized by low effective compression.

Crustal mechanics and rheology

Porjesz and Bergerat [2013] address the challenging ques-tion of the number of intact rock samples submitted to labo-ratory tests needed to reliably derive physical properties ofin situ rock mass, i.e the validity of the extrapolation of theparameters from centimetre scale to a large rock mass. Theyinvestigate the scale effects and the influence of disconti-nuities on the physical properties of the Campanian chalk ofBougival (France). By conducting geophysical investiga-tions on pillars of an underground quarry and rock physicsexperiments on samples, they show that the presence of dis-continuities (fractures, flints) has a major impact on theelastic properties (dynamic Young’s modulus and Poisson’sratio) whereas neither the size of the samples nor theoverburden rock thickness seem to significantly influencethese mechanical properties.

Le Pourhiet [2013] first describes in detail the analyticalsolution for the strain softening model associated toMohr-Coulomb non associated elasto-plastic flow rule. Shethen presents results for the formation of shear bands andthe related decrease in stress in materials exhibiting a Mohr-Coulomb yield stress, focusing especially on the so-calledstructural softening. A discussion on the possible shearband angles for the considered Mohr-Coulomb material isalso included, emphasizing some differences with previousmodels where the thickness of the shear bands was not ta-ken into account. The application of the semi-analytical re-sults is of great concern for researchers using numericalsimulations to study shear bands and strain localization.

The paper of Gudmundsson and Mohajeri [2013] dealswith the relations between the scaling exponents, entropies,and energies of fracture networks. Based on icelandicexamples, they demonstrate that there is a power law onfracture-length and show that there is an abrupt changepoint in the scaling exponent, suggesting that this point re-lates to the comparatively long and deep fractures changingfrom tension fractures to normal faults. This paper offers anoriginal approach since the authors apply concept of entro-py to fracture network at geological scale, and calculate itshowing a strong linear correlation between the scaling expo-nents and entropies. They finally discuss fracture formationand propagation from view point of energy balance.

Bull. Soc. géol. Fr., 2013, no 4-5

FAULTS, STRESSES AND MECHANICS OF THE UPPER CRUST 293

From ductile to brittle deformation

On the basis of a synthesis of field observations and tectonicstudies in the northern Cycladic islands (Greece), Lacombeet al. [2013] discuss the initiation, geometry and mechanicsof brittle faulting in exhuming metamorphic rocks that ex-perienced ductile to brittle transition in the footwall of thepost-orogenic extensional detachments. The influence ofpreexisting rheological and structural anisotropy, such asboudinage or precursory ductile or semi-brittle shear zoneson the initiation and geometry of brittle faults is emphasi-zed. The study also addresses the kinematics and the me-chanics of low-angle normal faults (inherited and newly-formed), the rupture mechanisms operating in foliated me-tamorphic rocks as well as the significance of paleostressreconstructions in anisotropic rock masses.

Augier et al. [2013] report field mapping and analyses ofbrittle faulting in the sedimentary cover of the Almanzoracorridor and the Huércal-Overa basins (Spain), as well as adetailed study of the ductile and ductile-brittle deformationin the footwall unit of the Filabres extensional shear zone.Their study reveals that these intramountane basins develo-ped as extensional basins partly during the latest stages oftectonic denudation of the Sierra de los Filabres, then wereweakly inverted under a ~N-S to NNW-SSE compressionthat resulted in the reactivation of normal faults and in aprogressive reduction of water exchange with the Atlanticocean proposed to be directly responsible for the Late Mio-cene salinity crises.

Active deformation and seismotectonics

Allanic and Gumiaux [2013] report direct evidence of seis-mogenic faults in the Lepontine Dome (Central Alps, Swit-zerland) previously considered as tectonically quiescent.They identify aligned clusters of microseismic events, whichguided further morpho-tectonic investigations that resultedin recognizing marked scarps, perturbation of the drainagesystem or shift of terminal moraines. Combining seismolo-gical, geological and morphological data allows locatingfour seismogenic faults the kinematics of which was cons-trained by fault-slip data and focal mechanisms. These newdata, which reveal to be coherent at all scales, provide newconstraints on the current stress regime going on in the Le-pontine Dome and could have implications for future seis-mic hazard studies.

Wu et al. [2013] use the Persistent Scatterers SAR Interfe-rometry (PSInSAR) technique to obtain high density defor-mation map and to estimate the slant range displacementrate (SRD rate) in the Tainan tableland in western Taiwan.Such study in Tainan city, the fourth largest metropolitanarea in Taiwan, is particularly important for evaluating thepotential seismogenic structures. A striking result is achange in interseismic deformation pattern compared toprevious studies investigating the same area from 1996 to1999, demonstrating that the interseismic deformation inthe area is not steady-state and is affected by significanttransient deformation, which could have implication on theseismic cycle.

Stresses and paleostresses in the earth crust (2):applications

The paper of Bergerat et al. [2013] combines analyses ofgeothermal measurements, brittle tectonic data and hydro-thermal mineralization in the Hvalfjördur geothermal fieldof Southwest Iceland, an interesting area because deeplyeroded and located very close to the active Icelandic rift,thus providing a three-dimensional view of similar elementsof old rift and present rift zones. Their combination of va-rious data provides constraints both about the structure atdepth and the water circulation. If paleostress analysis indi-cates a rather complex stress history, most of the geother-mal water appears to be conducted by vertical extensionfractures located at depth and explaining the abnormal geo-thermal gradient. The authors propose a model explainingthe relationships between the present-day thermal activityand the intrusive styles of the dykes with distance from avolcanic centre.

Choi et al. [2013] combined the analysis of faulting interms of paleostresses with rock mechanics data (frictioncurve deduced from tension fractures on fault planes affec-ted by friction, experimental Mohr failure envelope derivedfrom rock mechanic tests) in order to evaluate the changesof stress magnitudes during the tectonic history of theGyeongsang basin (Korea). This approach reveals to be po-werful to provide bounds on the ancient principal stress ma-gnitudes and to better constrain the geological history ofsedimentary basins that underwent a polyphase tectonicevolution, including changes in burial depths.

Using the fold-thrust belt of NW Taiwan as a case study,Chu et al. [2013] analyse striated micro-faults and otherfractures in order to elucidate their relationships with regio-nal folds and thrusts and regional tectonic stress. The obser-ved joint sets likely formed at depth during a pre-foldingstage. Later strike-slip faults accompanying thrusting andfolding have reactivated these pre-existing joint sets as slipplanes. Inversion of fault-slip data for stress reveal two ma-jor compression directions, oriented N110-120oE andN150-160oE respectively, which sheds light on the debateabout paleostress changes during the Taiwan mountain buil-ding process. This work also highlights a greater complexi-ty in interpreting joint sets in NW Taiwan than in earlierstudies focusing on individual fold structures.

Homberg et al. [2013] report new geometric, kinematic, se-dimentologic and bio-stratigraphic data on faults and faul-ted formations in order to constrain the Late Jurassic toEarly Cretaceous evolution of the Southeastern basin(France). The deformation mechanism in the basin drasti-cally changed in the Jurassic-Cretaceous transition, with thedirection of extension rotating from a WNW-ESE to aNNE-SSW direction. Lateral thickness variations of the se-quences, redistribution of sediments as well as faulting atvarious scales are interpreted in terms of an Early Creta-ceous tectono-stratigraphic reorganization of the basin, pos-sibly related to the rifting and later opening of the NorthAtlantic.

Bull. Soc. géol. Fr., 2013, no 4-5

294 LACOMBE O. and BERGERAT F.

FAULTS, STRESSES AND MECHANICS OF THE UPPER CRUST 295

PHOTO 6. – Illustration from a notebook of Jacques, drawn in 1999 and sho-wing a sketch of distance- meter measurements along the Chinyuan canal, Taiwan.

PHOTO 4. – Jacques measuring a right-lateral strike-slip fault in a Permiandyke, S. Sandby quarry, Scania Sweden, 2005.

PHOTO 5. – Jacques teaching during a French-Taiwanese fieldtrip, Taiwan,1995.

PHOTO 3. – Jacques at the restaurant terrace “La Baleine Joyeuse”, in Ville-franche-sur-mer, France, 2009.

PHOTO 1. – Jacques writing in his notebook in the Thingvellir fissure swarm,Iceland, 2006.

PHOTO 2. – Jacques at the Active Collision in Taiwan International Sympo-sium, Taipei, Taiwan, 1995.

Bull. Soc. géol. Fr., 2013, no 4-5

Acknowledgements. – The Guest Editors would like to thank all the reviewers who have played an important role in maintaining a high level of rigor to thescientific contributions, as well as TOTAL for financial support of the publication of this thematic issue.

References

Bull. Soc. géol. Fr., 2013, no 4-5

296 LACOMBE O. and BERGERAT F.

PHOTOS 8 and 9. – Meeting in the honor of Jacques, held in the University Pierre et Marie Curie, Paris, France, 2011.

PHOTO 7. – Jacques working with one ofhis former PhD student (Emmy T.Y.Chang) in the Yuli quarry, Taiwan, 2002.

AKI K. (1968). – Seismicity and seismological method. – Tectonophysics, 6(1), 834 41-58.

ALLANIC C. & GUMIAUX C. (2013). – Are there any active faults within theLepontine Dome (Central Alps)? In: O. LACOMBE and F. BERGERAT,Eds, Faults, stresses and mechanics of the upper crust: a tribute toJacques Angelier. – Bull. Soc. géol. Fr., 184, 4-5, 426-439.

AMONTON G. (1699). – De la résistance causée dans les machines. – Mémoi-res de mathématiques et de physique tirés des registres de l’Aca-démie Royale des Sciences de l’année M.DC.XCIX, 206-222.

ANDERSON E.M. (1905). – The dynamics of faulting. – Trans. EdinburghGeol. Soc., 8, 387-402.

ANGELIER J. (1975). – Sur l’analyse de mesures recueillies dans des sitesfaillés: l’utilité d’une confrontation entre les méthodes dynami-ques et cinématiques. – C.R. Acad. Sci., D, 281, 1805-1808.

ANGELIER J. (1984). – Tectonic analysis of fault slip data sets. – J. Geo-phys. Res., 89 (B7), 5835-5848.

AUGIER R., JOLIVET L., DO COUTO D. & NEGRO F. (2013). – From ductile tobrittle, late- to post-orogenic evolution of the Betic Cordillera:Structural insights from the northeastern internal zones In:O. LACOMBE and F. BERGERAT, Eds, Faults, stresses and mecha-nics of the upper crust: a tribute to Jacques Angelier. – Bull. Soc.géol. Fr., 184, 4-5, 405-425.

BERGERAT F., SÆMUNDSSON K., FOUREL L. & ANGELIER J. (2013). – Contri-bution and limit of brittle tectonic analyses and paleostress stu-dies in deciphering geothermal field functioning: the case studyof Hvalfjördur (Iceland). In: O. LACOMBE and F. BERGERAT, Eds,Faults, stresses and mechanics of the upper crust: a tribute toJacques Angelier. – Bull. Soc. géol. Fr., 184, 4-5, 451-465.

BOUCHON M. & KARABULUT H. (2008). – The aftershock signature of su-pershear earthquakes. – Science, 320, 1323-1325.

BOUCHON M., KARABULUT H, AKTAR M, OZALAYBEY S., SCHMITTBUHL J. &BOUIN M.P. (2011). – Extended nucleation of the 1999 M-w 7.6Izmit earthquake. – Science, 331, 6019, 877-880.

BYERLEE J.D. (1978). – Friction of rocks. – Pure and Applied Geophysics,116, 615-626.

BYERLY P. & STAUDER W.V. (1957). – Motion at the source of an ear-thquake. The mechanics of faulting with special reference to thefault-plane work (a Symposium), XX (2). – Publication of theDominion Observatory, Ottawa, pp. 255-261.

CAREY E. & BRUNIER B. (1974). – Analyse théorique et numérique d’unmodèle mécanique élémentaire appliqué à l’étude d’une popula-tion de failles. – C.R. Acad. Sci., D, 279, 891-894.

CÉLÉRIER B, ETCHECOPAR A., BERGERAT F., VERGELY P., ARTHAUD F. &LAURENT P. (2012). – Inferring stress from faulting: From earlyconcepts to inverse methods. – Tectonophysics, 581, 206-219.

CHOI P.-Y., ANGELIER J., CADET J.-P., HWANG J.-H. & SUNWOO C. (2013). –Change of stress magnitudes during the polyphase tectonic his-tory of the Cretaceous Gyeongsang basin, southeast Korea In:O. LACOMBE and F. BERGERAT, Eds, Faults, stresses and mecha-nics of the upper crust: a tribute to Jacques Angelier. – Bull. Soc.géol. Fr., 184, 4-5, 467-484.

CHU H.-T., LEE J.-C., BERGERAT F., HU J.-C., LIANG S.-H., LU C.-Y. & LEE

T.-Q. (2013). – Fracture patterns and their relations to mountainbuilding in a fold-thrust belt: A case study in NW Taiwan In:O. LACOMBE and F. BERGERAT, Eds, Faults, stresses and mecha-nics of the upper crust: a tribute to Jacques Angelier. – Bull. Soc.géol. Fr., 184, 4-5, 485-500.

COULOMB C.A. (1776). – Sur une application des règles maximis et mini-mis à quelques problèmes de statique relatifs à l’architecture. –Acad. Sci. Paris Mém. Math. Phys, 7, 343-382.

DAUBREE A. (1879). – Etudes synthétiques de géologie expérimentale. –Dunod, Paris.

DRAGERT H., WANG K & JAMES T.S. (2001). – A silent slip event on the dee-per Cascadia subduction interface. – Science, 292, 1525-1528

ETCHECOPAR A., VASSEUR G. & DAIGNÈRES M. (1981). – An inverse pro-blem in microtectonics for the determination of stress tensorsfrom fault striation analysis. – J. Struct. Geol., 3, 51-65.

ETCHECOPAR A., YAMADA T. & CHEUNG P. (2013). – Borehole images forassessing present day stresses In: O. LACOMBE and F. BERGERAT,Eds, Faults, stresses and mechanics of the upper crust: a tributeto Jacques Angelier. – Bull. Soc. géol. Fr., 184, 4-5, 307-318.

FAULKNER D.R., JACKSON C.A.L., LUNN R.J., SCHLISCHE R.W., SHIPTON

Z.K., WIBBERLEY C.A.J. & WITHJACK M.O. (2010). – A reviewof recent developments concerning the structure, mechanics andfluid flow properties of fault zones. – J. Struct. Geol., 32, 11,1557-1575.

GRIFFITH A.A. (1924). – Theory of rupture. In: C.B. BIEZENO and J.M.BURGES, Eds, Proceedings of the First International Congressfor Applied Mechanics, 55-63. – Int. Union of Theor. Appl.Mech., Delft., Netherlands.

GRIGGS D. & HANDIN J. (1960). – Observations on fracture and a hypothe-sis of earthquakes. In: D. GRIGGS and J. HANDIN, Eds, Rock de-formation. – Geol. Soc. Amer., Boulder, Colorado, 79, 347-364.

GUÐMUNDSSON A. & MOHAJERI N. (2013). – Relations between the scalingexponents, entropies and energies of fracture networks In:O. LACOMBE and F. BERGERAT, Eds, Faults, stresses and mecha-nics of the upper crust: a tribute to Jacques Angelier. – Bull. Soc.géol. Fr., 184, 4-5, 373-382.

HEIDBACH O., TINGAY M., BARTH A., REINECKER J., KURFESS D. & MULLER

B. (2010). – Global crustal stress pattern based on the worldstress map database release 2008. – Tectonophysics, 482 (1-4),3-15.

HOMBERG C, SCHNYDER J, & BENZAGGAGH M. (2013). – Late Jurassic-EarlyCretaceous faulting in the Southeastern French Basin: does it re-flect a tectonic reorganization? In: O. LACOMBE and F. BERGERAT,Eds, Faults, stresses and mechanics of the upper crust: a tribute toJacques Angelier. – Bull. Soc. géol. Fr., 184, 4-5, 501-514.

JAEGER J.C. (1959). – The frictional properties of joints in rock. – Geofisi-ca pura e applicata, 43, 148-158.

JAEGER J.C. (1960). – Shear fracture of anisotropic rocks. – Geol. Mag., 97,65-72.

LACOMBE O. (2012). – Do fault slip data inversions actually yield ‘paleos-tresses’ that can be compared with contemporary stresses? A cri-tical discussion. – C.R. Geoscience, 344, 159-173.

LACOMBE O., JOLIVET L., LE POURHIET L., LECOMTE E. & MEHL C. (2013). –Initiation, geometry and mechanics of brittle faulting in exhu-ming metamorphic rocks: Insights from the northern Cycladicislands (Aegean, Greece). In: O. LACOMBE and F. BERGERAT,Eds, Faults, stresses and mechanics of the upper crust: a tributeto Jacques Angelier. – Bull. Soc. géol. Fr., 184, 4-5, 363-403.

LE POURHIET L. (2013). – Strain localization due to structural softening du-ring pressure sensitive rate independent yielding. In: O. LACOMBE

and F. BERGERAT, Eds, Faults, stresses and mechanics of the uppercrust: a tribute to Jacques Angelier. – Bull. Soc. géol. Fr., 184,4-5, 357-371.

LISLE R.J. (2013). – A critical look at the Wallace-Bott hypothesis infault-slip analysis In: O. LACOMBE and F. BERGERAT, Eds, Faults,stresses and mechanics of the upper crust: a tribute to JacquesAngelier. – Bull. Soc. géol. Fr., 184, 4-5, 299-306.

MASSONNET D., ROSSI M., CARMONA C., ADRAGNA F., PELTZER G., FEIGL K.& RABAUTE T. (1993). – The displacement field of the Landersearthquake mapped by radar interferometry. – Nature, 364,138-142.

MATTAUER M. & MERCIER J.L. (1980). – Microtectonique et grande tecto-nique. – Livre jubilaire du Cent Cinquantenaire 1830-1980. –Mém. H.S. Soc. géol. Fr., 10, 141-161.

MAURY J., CORNET F.H. & DORBATH L. (2013). – A review of methods fordetermining stress fields from earthquakes focal mechanisms;Application to the Sierentz 1980 seismic crisis (Upper RhineGraben) In: O. LACOMBE and F. BERGERAT, Eds, Faults, stressesand mechanics of the upper crust: a tribute to Jacques Angelier. –Bull. Soc. géol. Fr., 184, 4-5, 319-334.

MCKENZIE D.P. (1969). – The relation between fault plane solutions for ear-thquakes and the directions of the principal stresses. – Bull. Seis-mol. Soc. Am., 59, 591-601.

MOHR O. (1900). – Welche Umstände bedingen die Elastizitätsgrenze undden Bruch eines Materials. – Zeitschrift des Vereins DeutscherIngenieure, 44, 1524-1530 & 1572-1577.

POLLARD D.D. & AYDIN A. (1988). – Progress in understanding jointingover the past century. – Geol. Soc. Amer. Bull., 100, 1181-1204.

PORJESZ R & BERGERAT F. (2013). – Scale effect and impact of discontinui-ties in the dynamic elastic constants of the Campanian chalk ofBougival (France) In: O. LACOMBE and F. BERGERAT, Eds, Faults,stresses and mechanics of the upper crust: a tribute to JacquesAngelier. – Bull. Soc. géol. Fr., 184, 4-5, 347-355.

REBETSKY Y.L. & TATEVOSSIAN R.E. (2013). – Rupture propagation instrong earthquake sources and tectonic stress field In: O.LACOMBE and F. BERGERAT, Eds, Faults, stresses and mechanicsof the upper crust: a tribute to Jacques Angelier. – Bull. Soc.géol. Fr., 184, 4-5, 335-346.

RICE J.R. (1973). – The initiation and growth of shear bands. In: A.C. PALMER,Ed., Plasticity and soil mechanics. – Cambridge Univ. Press, Cam-bridge, U. K., 263-274.

SCHMITT D.R., CURRIE C.A. & ZHANG L. (2012). – Crustal stress determi-nation from boreholes and rock cores: Fundamental principles. –Tectonophysics, 580, 1-26

SEGALL P. & DAVIS J.L. (1997). – GPS applications for geodynamics andearthquake studies. – Ann. Rev. Earth Planet. Sci., 25, 301-336

SIBSON R.H. (1985). – A note on fault reactivation. – J. Struct. Geol., 7 (6),751-754.

TOWNEND J. & ZOBACK M.D. (2000). – How faulting keeps the crust strong. –Geology, 28, 5, 399-402

WU Y.-Y., HU J.-C., LIN G.-P., CHANG C.-P., TUNG H. & LU C.-H. (2013). –Transient active deformation in Tainan tableland using persistentscatterers SAR interferometry. In: O. LACOMBE and F. BERGERAT,Eds, Faults, stresses and mechanics of the upper crust: a tributeto Jacques Angelier. – Bull. Soc. géol. Fr., 184, 4-5, 441-450.

ZOBACK M.L., ZOBACK M.D., ADAMS J., ASSUMPCAO M., BELL S., BERGMAN

E.A., BLUMLING P., BRERETON N.R., DENHAM D., DING J., FUCHS

K., GAY N., GREGERSEN S., GUPTA H.K., GVISHIANI A., JACOB K.,KLEIN R., KNOLL P., MAGEE M., MERCIER J.L., MULLER B.C.,PAQUIN C., RAJENDRAN K., STEPHANSSON O., SUAREZ G., SUTER

M., UDIAS A., XU Z.H. & ZHIZHIN M. (1989). – Global patternsof tectonic stress. – Nature, 341, 291-298.

Bull. Soc. géol. Fr., 2013, no 4-5

FAULTS, STRESSES AND MECHANICS OF THE UPPER CRUST 297