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Two anhydrous equilibria can be written among the components of stilpnomelane, chlorite, white mica and quartz, namely 89 daphnite+131 Fe-celadonite+190 quartz=96 stilpnomelane+71 muscovite, and amesite+Mg-celadonite=muscovite+clinochlore. We assume that the free energy change of reaction, ΔG=ΔGo+ΣRT lnaij, is approximated by ΔG=A?BT +C(P?1)+ΣRT lnaij, where ΔGo is the free energy change of the end-member components at temperature T and pressure P, ai is the activity of component i whose coefficient in the equilibrium is j, and A, B and C are constants to be determined. Values of C can be approximated by the change in volume on reaction, namely C=406.517 J/bar for the first reaction and C=0.613 J/bar for the second reaction. Constants A and B were determined by using six occurrences of the assemblage stilpnomelane–chlorite–white mica for which P–T have been otherwise estimated. Using solution models from the literature, linear regression gives for the first equation A=?6118.269 kJ, B=?4584.09 J/K, and for the second equation A=19.397 kJ, B=66.72 J/K. These values predict P–T within 0.5 kbar and 25 K for all occurrences, and appear reasonably robust relative to probable analytical errors. P–T are determined by intersection of the curves generated by given compositions in P–T space. Fine-grained and/or zoned chlorite and white mica make application of the geothermobarometer difficult in some instances, but our work in the Bathurst region of New Brunswick suggests that, with patience and care, useful analyses can be obtained, and the database for the geothermobarometer greatly expanded.  相似文献   

4.
A petrologic problem of fundamental importance is to determine whether 2 or more mineral assemblages can be related to one another by continuous or discontinuous facies changes, or whether their bulk compositions occupy non-overlapping regions of composition space. A general method is developed by which 2 regions of n-dimensional space whose vertices are defined by the phases present are tested for compositional overlap. This is accomplished by generating mass balance equations of the type:
∑i = 1m aiAi = ∑j = 1k bjBj
where Ai is the ith phase in one region and Bj is the th phase in the other. If any such equation satisfies the requirement that the sign of each ai is the same, and that the sign of each bj is the opposite for all i, j such that: k + m = n + 1 then the 2 regions overlap in phase space.By eliminating all overlapping assemblages in a given set, the bivariant fields bounded by univariant equilibria in n-dimensional systems are completely specified. All bulk compositions are considered within the space defined by the phases that participate in the bounding reactions. An extension of the method generates in sequence all bivariant fields and associated reactions about any invariant point. A further extension is applied to multi-system analysis.  相似文献   

5.
The association between constant-sum variables Xi and Xj expressed as percentages can be calculated as a product-moment correlation between Xi and Xj/(100 – Xi ) and a correlation between Xj and Xi/(100 – Xj ). An asymmetric, square matrix may be formed from these coefficients, and multivariate analysis performed by two methods: singular value decomposition and canonical decomposition. Either analysis avoids problems in the interpretation of correlation coefficients determined from closed arrays, and provides information about dependencies among the variables beyond that obtained from the usual correlation coefficient between Xi and Xj.Two examples show the canonical decomposition to have the greater usefulness.  相似文献   

6.
Computation of the seismic stability of rock wedges   总被引：1，自引：0，他引：1  
Summary Newmark's concept of computing the permanent displacement under seismic loads has been combined with the conventional limit equilibrium analysis to compute the displacements of a rock wedge. The rock wedge formed by the intersecting planes may or may not have a tension crack in the upper slope surface. As the static analysis of a rock wedge is available from the literature, only the seismic problem is treated theoretically in more details.A computer program has been developed to compute the displacements from the digitised input data of the acceleration-time-history. The program can take into account the water pressure on the intersecting planes and on the planes of the tension crack. The effect of rock anchors if present is also taken care of in addition to static surcharge loads. The program calculates the conventional static factor of safety, remaining resistance against sliding, the critical acceleration, exciting force, relative velocity with time and the cumulative displacements.Two model examples are presented: one with simple sinusoidal acceleration and the other one with actual earthquake data considering the different systems of forces acting on the wedge. The results are critically discussed with respect to the different parameters e. g. anchor forces, water pressure and cohesion influencing the magnitude of displacements under seismic loads. It is shown that the critical acceleration is a better index for the seismic stability than the conventional factor of safety.The critical acceleration presented in this paper serves as a very handy tool for a site engineer to get the first hand information about the stability of the wedge for a given acceleration-time-history without going into the details of dynamic analysis.Notations A, B Inclined intersecting planes - C, D Geometric points on the intersection ofA andB - a cr Critical acceleration - a h Horizontal acceleration - a v Vertical acceleration - a r Relative acceleration of the wedge - DF Driving force - DF dyn Dynamic driving force - DF st Static driving force - FS Factor of safety - g Acceleration due to gravity - m Mass of the wedge - RF Resisting force - RF dyn Dynamic resisting force - RF st Static resisting force - RS Remaining resisting force against sliding - RS dyn Total seismic induced force - RS st Remaining static resisting force against sliding - s r Cumulative relative displacement of the wedge - TRS Total remaining resisting force against sliding - v r Relative velocity of the wedge - W Weight of the wedge - W A ,W B Weight of the wedge in the planeA andB - Dip of line of intersection of the planesA andB - Average friction angle - A , B Friction angle of planeA andB - I, II, III, IV Points in the curve shown in Fig. 6  相似文献   

7.
The hazard rate, the number of fracture occurrences per unit time, which has been obtained from laboratory experiments of rock fracture, is obtained for the earth's crust by analysing the statistical distribution of geodetically-observed ultimate strain. The associated hazard function has two coefficients, A and B, to be determined. Comparison of the coefficients obtained by the results of rock-fracture experiments with the geodetically determined ones discloses that B is independent of the size-effect. It is therefore concluded that, if A is estimated from the statistics of the geodetically observed ultimate strain and B is obtained from fracture experiments of rock forming a local part of the crust, the probability of a local large-scale earthquake occurrence can be estimated.  相似文献   

8.
Phase transitions in MgGeO3 and ZnGeO3 were examined up to 26 GPa and 2,073 K to determine ilmenite–perovskite transition boundaries. In both systems, the perovskite phases were converted to lithium niobate structure on release of pressure. The ilmenite–perovskite boundaries have negative slopes and are expressed as P(GPa)=38.4–0.0082T(K) and P(GPa)=27.4−0.0032T(K), respectively, for MgGeO3 and ZnGeO3. Enthalpies of SrGeO3 polymorphs were measured by high-temperature calorimetry. The enthalpies of SrGeO3 pseudowollasonite–walstromite and walstromite–perovskite transitions at 298 K were determined to be 6.0±8.6 and 48.9±5.8 kJ/mol, respectively. The calculated transition boundaries of SrGeO3, using the measured enthalpy data, were consistent with the boundaries determined by previous high-pressure experiments. Enthalpy of formation (ΔH f°) of SrGeO3 perovskite from the constituent oxides at 298 K was determined to be −73.6±5.6 kJ/mol by calorimetric measurements. Thermodynamic analysis of the ilmenite–perovskite transition boundaries in MgGeO3 and ZnGeO3 and the boundary of formation of SrSiO3 perovskite provided transition enthalpies that were used to estimate enthalpies of formation of the perovskites. The ΔH f° of MgGeO3, ZnGeO3 and SrSiO3 perovskites from constituent oxides were 10.2±4.5, 33.8±7.2 and −3.0±2.2 kJ/mol, respectively. The present data on enthalpies of formation of the above high-pressure perovskites were combined with published data for A2+B4+O3 perovskites stable at both atmospheric and high pressures to explore the relationship between ΔH f° and ionic radii of eightfold coordinated A2+ (R A) and sixfold coordinated B4+ (R B) cations. The results show that enthalpy of formation of A2+B4+O3 perovskite increases with decreasing R A and R B. The relationship between the enthalpy of formation and tolerance factor ( R o: O2− radius) is not straightforward; however, a linear relationship was found between the enthalpy of formation and the sum of squares of deviations of A2+ and B4+ radii from ideal sizes in the perovskite structure. A diagram showing enthalpy of formation of perovskite as a function of A2+ and B4+ radii indicates a systematic change with equienthalpy curves. These relationships of ΔH f° with R A and R B can be used to estimate enthalpies of formation of perovskites, which have not yet been synthesized.  相似文献   

9.
B. Py 《Mineralium Deposita》1994,29(1):281-285
One of the very few disadvantages of the mass-transfer transducer when compared with the hot-film sensor, is a slightly diminished frequency-response due to the higher Prandtl number encountered. Mass or thermal balance and transfer equations were solved first by Fortuna and Hanratty (1971) for small fluctuations of the wall shear. The solutions allow to make accurate corrections on the frequency spectra and the power of the fluctuations, but in different time. In this paper, the author deduces the frequency response of split rectangular electrodes and shows how a combination of signals improves the response at higher frequencies and makes it comparable to the thermal transducer with the same size, in the same fluid. Two experimental devices are described and compared. With these devices, the measurement of the wall shear fluctuations is improved in real time. Accurate determinations of turbulent power fluctuations and probability density spectra are feasible and illustrate the subject.List of Symbols A total area of the electrode - A j area of the partj of the electrode - a coefficient - C concentration - C bulk concentration - c fluctuation of concentration - D diffusion coefficient - F Faraday's constant - f(n +) transfer function - g gain of the differential electrode - I j electrolysis current on the partj of the electrode - K transfert coefficient - k fluctuation ofK - l electrode length - n frequency - P r Prandtl number - S wall shear - s fluctuation of the wall-shear - t time - x direction of the flow - y direction normal to the wall - phase delay - kinematic viscosity A version of this paper was presented at the 11th Symposium on Turbulence, University of Missouri-Rolla, 17–19 October 1988  相似文献   

10.
Metagabbro bodies in SW Grenville Province display a variety of disequilibrium corona textures between spinel-clouded plagioclase and primary olivine or opaque oxide. Textural evidence favours a single-stage, subsolidus origin for the olivine coronas and diffusive mass transfer is believed to have been the rate-controlling process. Irreversible thermodynamics have been used to model two different garnet symplectite-bearing corona sequences in terms of steady state diffusion. In the models the flux of each component is related to the chemical potential gradients of all diffusing species by the Onsager or L-coefficients for diffusion. These coefficients are analogous to experimentally determined diffusion coefficients (d), but relate the flux of components to chemical potential rather than concentration gradients.The major constraint on the relative values of Onsager coefficients comes from the observed mole fraction, X, of garnet in the symplectites; in (amph-gt) symplectites X Gt Sym 0.80, compared with 0.75 in (cpx-gt) symplectites. Several models using simple oxide components, and two different modifications of the reactant plagioclase composition, give the following qualitative results: the very low mobility of aluminium appears to control the rate of corona formation. Mg and Fe have similar mobility, and Mg can be up to 6–8 times more mobile than sodium. Determination of calcium mobility is problematical because of a proposed interaction with cross-coefficient terms reflecting uphill Ca-diffusion, i.e., calcium diffusing up its own chemical potential gradient. If these terms are not introduced, it is difficult to generate the required proportions of garnet in the symplectite. However, at moderate values of the cross-coefficient ratios, Mg can be up to 4–6 times more mobile than calcium (L MgMg/LCaCa<4–6) and="" calcium="" must="" be="" 3–4="" times="" more="" mobile="" than="" aluminium="">L CaCa/LAlAl>3).  相似文献   

11.
Total mass-to-light ratio M/L B for S0 — Irr galaxies, whereM is the dynamical mass within the optical radius R 25 (corresponding to 25 m /sq. arcsec in the B band), increases systematically with (B-V)0 color, but slower than that is predicted by stellar population evolution models without dark halo. It shows that the mean ratio between dark halo and stellar masses is higher for more “blue“ galaxies. However some galaxies don’t follow this general trend. The properties of galaxies with extremely high and extremely low values of M/L B ratios are compared, and different factors, accounting for the extremes, are analyzed. The conclusion is that in some cases too high or too low M/L B ratios are associated with observational errors, in other cases—with non-typical dark halo mass fraction, and in some cases — with peculiarities of disc stellar population. Particularly, discs of some galaxies with low M/L B ratios turn out to be unusually “light” for their luminosity and colors, which indicates a substantial deficit of low mass stars as the most probable cause of low M/L B .  相似文献   

12.
Samples of monomineralic quartz veins from the Simplon Fault Zone in southwest Switzerland and north Italy generally have asymmetric, single girdle c-axis patterns similar to textures measured from many other regions. Several samples have characteristically different textures, however, with a strong single c-axis maximum near the intermediate specimen axis Y (the direction within the foliation perpendicular to the lineation X) and a tendency for the other crystal directions to be weakly constrained in their orientation about this dominant c-axis maximum. This results in ‘streaked’ pole figure patterns, with an axis of rotation parallel to the c-axis maximum. These atypical samples also have a distinctive optical microstructure, with advanced recrystallization and grain growth resulting in a strong shape fabric (SB) oblique to the dominant regional foliation (SA), whereas typical samples have a strong SA fabric outlined by very elongate, only partially recrystallized, ribbon grains. The recrystallized grains of the atypical samples are themselves deformed and show strong undulose extinction and a core-mantle recrystallization structure. The streaked texture is likely to be a direct consequence of lattice bending and kinking during heterogeneous slip on the favoured first-order prism (10 0) (a) system, the heterogeneity itself being due to problems in maintaining coherence across grain boundaries when insufficient independent easy-slip systems are available for homogeneous strain by dislocation glide. Such bending would be particularly prevalent in very elongate, thin ribbon grains, resulting in high internal strain energy and promoting recrystallization. Thus both the texture and the microstructure could be significantly modified by later strain increments affecting quartz grains with an already developed, nearly single-crystal texture.  相似文献   

13.
G. Ramadass 《地学学报》1990,2(2):160-166
Regional gravity, magnetic and radiometric surveys were conducted in the Sunkalagaripalle–Rekhalakunta area of the Cuddapah basin, Andhra Pradesh, India. Since the Geophysical anomalies of this area are of very low amplitude, a new filter Mj, was generated, using the Hilbert Transform in order to enhance the signal from its noisy background. Filter Mj is the summation of the multiplied values of the horizontal derivative of the anomaly and its corresponding Hilbert Transform (or vertical gradient), computed three at a time (three point data window) starting from one end of the profile. The process was repeated by sliding the data window along the entire profile, the Filter Mj was convolved with the first horizontal derivative (Mj×A) and with its Hilbert Transform (Mj, ×H). Resolved gravimagnetic and radiometric signals were then correlated with contacts and faults etc. Such studies are shown to be of value for the qualitative interpretation of noisy geophysical data.  相似文献   

14.
A study of the lithogeochemistry of metavolcanics in the Ben Nevis area of Ontario, Canada has shown that factor analysis methods can distinguish lithogeochemical trends related to different geological processes, most notably, the principal compositional variation related to the volcanic stratigraphy and zones of carbonate alteration associated with the presence of sulphides and gold. Auto- and cross-correlation functions have been estimated for the two-dimensional distribution of various elements in the area. These functions allow computation of spatial factors in which patterns of multivariate relationships are dependent upon the spatial auto- and cross-correlation of the components. Because of the anisotropy of primary compositions of the volcanics, some spatial factor patterns are difficult to interpret. Isotropically distributed variables such as CO 2 are delineated clearly in spatial factor maps. For anisotropically distributed variables (SiO 2 ), as the neighborhood becomes smaller, the spacial factor maps becomes better. Interpretation of spatial factors requires computation of the corresponding amplitude vectors from the eigenvalue solution. This vector reflects relative amplitudes by which the variables follow the spatial factors. Instability of some eigenvalue solutions requires that caution be used in interpreting the resulting factor patterns. A measure of the predictive power of the spatial factors can be determined from autocorrelation coefficients and squared multiple correlation coefficients that indicate which variables are significant in any given factor. The spatial factor approach utilizes spatial relationships of variables in conjunction with systematic variation of variables representing geological processes. This approach can yield potential exploration targets based on the spatial continuity of alteration haloes that reflect mineralization.List of symbols c i Scalar factor that minimizes the discrepancy between andU i - D Radius of circular neighborhood used for estimating auto- and cross-correlation coefficients - d Distance for which transition matrixU is estimated - d ij Distance between observed valuesi andj - E Expected value - E i Row vector of residuals in the standardized model - F(d ij) Quadratic function of distanced ij F(d ij)=a+bd ij+cd ij 2 - L Diagonal matrix of the eigenvalues ofU - i Eigenvalue of the matrixU;ith diagonal element ofL - N Number of observations - p Number of variables - Q Total predictive power ofU - R Correlation matrix of the variables - R 0j Variance-covariance signal matrix of the standardized variables at origin;j is the index related tod andD (e.g.,j=1 ford=500 m,D=1000 m) - R 1j Matrix of auto- and cross-correlation coefficients evaluated at a given distance within the neighborhood - R m 2 Multiple correlation coefficient squared for themth variable - S i Column vectori of the signal values - s k 2 Residual variance for variablek - T i Amplitude vector corresponding toV i;ith row ofT=V –1 - T Total variation in the system - U Nonsymmetric transition matrix formed by post-multiplyingR 01 –1 byR ij - U i Componenti of the matrixU, corresponding to theith eigenvectorV i;U i= iViTi - U* i ComponentU i multiplied byc i - U ij Sum of componentsU i+U j - V i Eigenvector of the matrixU;ith column ofV withUV=VL - w Weighting factor; equal to the ratio of two eigenvalues - X i Random variable at pointi - x i Value of random variable at pointi - y i Residual ofx i - Z i Row vectori for the standardized variables - z i Standardized value of variable  相似文献   

15.
We consider kinematic inhomogeneities (stellar groups) in the corona of the Ursa Major flow. We show that the orientation of the major axis of the error ellipse for each star is defined by its position relative to its own apex. We apply the AD-diagram method suggested by us earlier; a statistical analysis confirms the existence of stellar groups in the corona of the Ursa Major flow.  相似文献   

16.
In this paper, a new generator algorithm and a computer program PG2D is introduced for 2D numerical simulation of packing configuration in a granular material composed of elliptical particles of different a/b aspect ratios. Each elliptical particle is approximated by four connected arcs. The centre co-ordinates and radius of each arc and co-ordinates of connecting points can be determined from the formulae derived by entering the major axis length, 2a, and the eccentricity. The domain to be filled with particles can be a polygon of any shape. Given the size of the packing domain, geometrical information and numbers of particles to be generated, the packing location of each particle and the co-ordinates of contact points along with contact normal rose diagram can be generated as outputs. Simulation results show that this new algorithm can provide quite a reasonable packing model in accordance with the initial input required for the analysis of the mechanics of granular material. This generation scheme has the potential to cover packing generation and behaviour analysis of 3D sphere or ellipsoidal shaped granular materials. © 1997 by John Wiley & Sons, Ltd.  相似文献   

17.
A technique for IR spectroscopic determination of the total nitrogen content N S in the form of A-and B 1-defects is suggested. It provides for the computer processing and decomposition of IR spectra into constituent bands, calculation of the total absorption band area S N and individual areas S A and S B1 and their normalization with respect to the total area of the diamond intrinsic absorption S 0, with the normalization coefficients K S , K A , and K B1 being calculated. Based on the analysis of the IR spectra of 60 octahedral diamond crystals from the Mir and Yubileinaya pipes (Sakha-Yakutiya), the empirical functions N S = 911.85 K S 0.9919 ppm (R 2 = 0.9859), N A = 1185.6 K A 1.1511 ppm (R 2 = 0.8703), and N B1 = 911.85 K S 0.9919 ? 1185.6 K A 1.1511 ppm have been defined.  相似文献   

18.
Zusammenfassung Zusammenfassend ergibt sich aus der Untersuchung der Profile einer podsolierten Para-Braunerde and Para-Rendsina auf eihem kalkig gebundenen, feldspatreichen Sandstein des unteren Stubensandsteins folgender Verlauf der Verwitterung:Zunächst wird das kalkige Bindemittel herausgelöst. Dadurch entsteht ein hochporöses, hochdurchässiges Gerüst.Die Verwitterung zeigt sick im wesentlichen in einer Veränderung der Feldspite und einer Tonrnineralumbildung: Die Feldspäte warden aufgelöst, verbunden mit einern Kornzerfall in den Horizonten f (A1), Bfe und Ahe. Der primäre Illit verliert irn Verlauf der Verwitterung K+-Ionen und billet lurch Einlagerung von H3O+-Ionen quellfähige Schichten. Rises Entwicklung zeichnet sich vorwiegend im Oberboden ab. Dutch Einlagerung von Aluminiumhydroxid in die Zwischenschichten entsteht ein 14 Å-Mineral, vorwiegend im Bfe-Horizont.In dem wegen der Entkalkung hochporösen, hochdurchlässigen laden werden feinstkörnige Tonanteile durch herabsickerndes Wasser inechanisch verlagert. Dabei komInt es zu einer bevorzugten Anreicherung des feinerkörnigen Illits und des Mixed-Layer Illit-Montmorillonit im B t -Horizont, zurückbleibt das 14 Å-Mineral im Bfe-Horizont. Die Anreicherung im B t -Horizont führt zur Bildung eines auffallend plastischen Sandes (Honigsand).
Soil formation on calcite-cemented sandstone of the Middle Keuper (Stubensarldstein) is, studied in two profiles (Podsolierte Para-Braunerde and Para-Rendsina).The main results of weathering are: dissolution of calcite, alteration of feldspars and changes in the clay mineral composition.Solution of feldspars along cleavages and subsequent mechanical desintegration have caused a concentration of fine sand and silt in the top soil.Of the clay minerals in the soils, kaolinite, illite and part of the mixed layer illite-montmorillonite are inherited from the parent material.A. 14 Å mineral is restricted to the Bfe- and f(A1)-horizons of the podsolic profile. Ionic complexes of aluminium and hydroxyl released during feldspar alteration were fixed between the montmorillonite layers of the mixed layer mineral. This process, plus continuing supply of montmorillonite layers by the depletion of illite layers, resulted in the 14 Å mineral.The illite and the mixed layer mineral were found to be finer grained than the 14 Å mineral. Thus, the latter remained in the Bfe- and f(A1)-horizons, whereas the former minerals were washed down in the highly porous soil and concentrated in the Bt-horizon.
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19.
We have used 2-D finite element modelling to investigate the influence of a permanent low-viscosity layer between matrix and inclusion on matrix flow and inclusion rotation under viscous simple shear flow. Rigid inclusions of different shape (circle, square, ellipse, lozenge, rectangle and skewed rectangles) and aspect ratio (R) were used. The calculated matrix flow pattern is neither bow tie nor eye-shaped. It is a new flow pattern that we call cat eyes-shaped, which is characterized by: (i) straight streamlines that slightly bend inwards at the inclusion's crests; (ii) elongate eye-shaped streamlines on each side of the inclusion; (iii) stagnation points in the centre of the eyes; (iv) absence of closed streamlines surrounding the inclusion; (v) changes in flow configuration with inclusion orientation; the lines of flow reversal bend and tilt, closed streamline circuits may disappear, and streamlines may bend outwards at the inclusion's crests.Concerning inclusion rotation, the numerical results show that: (i) a low-viscosity layer (LVL) makes inclusions with R = 1 rotate synthetically, but the rotation rate depends upon shape (circle or square) and orientation. Therefore, shape matters in the slipping mode. (ii) All studied shapes with R > 1 rotate antithetically when starting with the greatest principal axis (e1) parallel to the shear direction ( = 0°); (iii) rotation is limited because there is a stable equilibrium orientation (se) for all studied shapes with R > 1. (iii) There is also an unstable equilibrium orientation (ue), and both se and ue depend upon inclusion's R and shape.The present numerical results closely agree with previous results of analogue experiments with a permanent low viscosity interface. Only minor deviations related with small shape differences were detected.  相似文献   

20.
We investigated moment tensors (MTs) of 70 events of the earthquake swarm which occurred in January 1997 in NW Bohemia. A refined location using the master-event procedure shows that all the foci clustered in a volume of less than 0.5 km3 comprising two compact clusters—the southern and northern ones. The results of single-source, absolute-moment tensor inversion of the P- and SH-peak amplitudes reveal two types of the source mechanisms, A and B in our denotation, which dominated in the swarm. Type A implies an oblique normal faulting with a nearly pure double-couple (DC) source. For the B type, an oblique-thrust faulting and a combined source [double-couple combined with the isotropic (ISO) and compensated linear-vector dipole (CLVD) components] are typical. Magnitudes of the non-double-couple components of MT appear unrelated to the ML magnitude of the event. The proximity of hypocentres of A and B events guarantees the non-double-couple source mechanisms of the B events not to be an artefact of a mismodelling of the medium. To exclude finiteness of the focus or station-site effects as possible causes of spurious non-double-couple components of MTs of the B events, the residuals of the peak amplitudes across the set of the B events were analysed and the jack-knife test was applied. The A and B events separate in time and space. Consequently, three major phases of swarm activity can be distinguished. In the first, only the southern cluster was active and A events prevailed, while B events dominated in the northern cluster in the third phase. Both A and B events occurred (the former in the southern cluster, the latter in the northern one) during the second phase. The initiation of the B events in the northern cluster are reflected in a pronounced increase in the non-double-couple components of the MTs, which points to tensile-source mechanisms as a consequence of a hypothesised fluid injection.  相似文献   

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