Sagy, A., Cohen G., Z. Reches, and J. Fineberg, 2006Dynamic fracture of granular material under quasi-static loading. J. Geophy. Res. (in press). Full text (PDF)

Katz O., and Reches Z., 2005, Reverse drag: post-failure deformation along existing faults. Submitted  to Israel J Earth Sciences  Full text (PDF)

Sagy A. and Z. Reches, 2005. Joint intensity in sedimentary rocks: The unsaturated, saturated, supersaturated, and clustered classes. Submitted  to Israel J Earth Sciences Full text (PDF)

Wilson B., T.A. Dewers, Z. Reches, and J. Brune, 2004, Texture and Energetics of Gouge Powder from Earthquake Rupture Zones . Nature (in revision). Full text (PDF)

Reches Z. and T.A. Dewers, 2004, Gouge Formation by Dynamic Pulverization During Earthquakes. (Submitted to EPSL).
Full text (PDF)

Sagy A., Fineberg J.,and Reches Z., 2004, Shatter Cones: Branched, Rapid Fractures Formed by Shock Impact. (J. Geoph. Res., in press)  Full text (PDF)

Katz O., and Reches Z., 2004, Microfracturing, damage and failure of brittle granites. J. Geophy. Res. 109 (B1), pp. 1206.  Full text (PDF)  

Muhuri, S. K., T. A. Dewers, T.E. Scott (Jr), and Z. Reches, 2003, Interseismic fault strengthening and earthquake slip
instability: friction or cohesion?. Geology, 31, 881–884. Full text (PDF)

Sagy, A., Z. Reches, and A. Agnon, 2003, Hierarchic three-dimensional structure and slip partitioning in the western Dead Sea pull-apart. Tectonics, v. 22 (1).  Full text (PDF)  

Katz O., Reches Z. and Baer G., 2003, Faults and their associated host rock deformation: Structure of small faults in a quartz-syenite body, southern Israel. (J Structural Geology, 25, 1675-1689). Full text (PDF)  

Katz O., and Reches Z, 2002, Pre-failure damage, time-dependent creep and strength variations of a brittle granite. Proceedings 5th Int. Conf. on Analysis of Discontinuous Deformation, Ben-Gurion Univ., Balkema, Rotterdam Full text (PDF)

Sagy A., Reches Z. and Fineberg J., 2002, Dynamic fracture by large extraterrestrial impacts as the origin of shatter-cones. (Nature, 418, 310-313). For this paper Amir Sagy received the Ramsay Medal, 2003, by The Tectonic Study Group, UK (best publication arising directly from a PhD project in the field of tectonics and structural geology). Full text (PDF)

Bartov Y., M. Stein, Y. Enzel, A. Agnon and Z. Reches, 2002, Lake Levels and Sequence Stratigraphy of Lake Lisan, the Late Pleistocene Precursor of the Dead Sea, Quaternary Research, v. 57, 9-21. Full text (PDF)

Dor, O., Z. Reches, & G. van Aswagen, 2001, Fault zones associated with the Matjhabeng earthquake, 1999, South Africa. Rockburst and Seismicity in Mines, RaSiM5 (Proceedings), South African Inst. Of Mining and Metallurgy, pp. 109-112.  Full text (PDF)

Sagy, A., Z. Reches, and I Roman, 2001, Dynamic Fracturing: Field and Experimental Observations, J. of Structural Geology, 23 1223-1239. Full text(PDF)

Katz, O., Reches, Z., and J-C. Roegiers, 2000, Evaluation of mechanical rock properties using a Schmidt Hammer, Int. J. of Rock Mech. & Min. Sci., 37, 723-728. Full text(html)

 Reches, Z., 1999, Mechanisms of slip nucleation during earthquakes, Earth & Palnetary Science Letters, 170, 475-486.  Full text

 
Lioubashevski, O., Hamiel, Y., Agnon, A. Reches, Z., and J. Fineberg, 1999, Oscillons and propagating solitary waves in a vertically vibrated colloidal suspension, Phy. Rev. Lett., E, 83, 3190-3193.  Full text (.pdf)

 
Reches, Z., 1998, Tensile fracturing of stiff rock layers under triaxial compressive stress states 3rd NARMS, Mexcio, June, 1998, Int. J. of Rock Mech. & Min. Sci. 35: 4-5, Paper No. 70.  Full text(html)

 
Reches, Z., and Eidelman A., 1995, Drag along faults, Tectonophysics, v. 247, 145-156.  Abstract

Reches, Z., Baer, G. and Hatzor Y., 1992, Constraints on the strength of the upper crust from stress inversion of fault slip measurements, J. Geophysical Res., 97, 12,481-12,493.  Abstract

Reches, Z., Erez, Y. and Garfunkel Z., 1987, Sedimentary and tectonic features in the northwestern Gulf of Elat, Israel, Tectonophysics, 141, 169-180. 

Reches, Z., 1987, Mechanical aspects of pull-apart basins and push-up swells with applications to the Dead Sea transform, Tectonophysics, 141, 75-88. 

Baer, G. and Z. Reches, 1987, Flow patterns of magma in dikes, Makhtesh Ramon, Israel, Geology, 15, 569-572. 

Reches, Z., 1986, The development of a fracture network by shear: Experimental results, Proc. of 27 U.S. Symp. on Rock Mechanics, June, 1986, Alabama, 141-145. 

Reches, Z., 1986, Networks of shear faults in the field and in experiments, in Jaeger Z. and Engelman B. (editors), Proc. of 3F conf., Neve Ilan, Jan. 1986, Ann. of Israel Physics Soc., 42- 52. 

Fink, J. and Z. Reches, 1985, Diagenetic density inversions and the deformation of hallow marine chert beds in Israel (reply). Sedimentology, 32, 461-464. 

Eyal, Y. and Z. Reches, 1983, Tectonic analysis of the Dead Sea Rift region since the Late-Cretaceous based on mesostructures, Tectonics, 2, 167-185. 

Fink, J. and Z. Reches, 1983, Diagenetic density inversions and the deformation of shallow marine chert beds in Israel, Sedimentology, 30, 261-271. 

Reches, Z., 1983, Faulting of rocks in three dimensional strain fields II. Theoretical analysis, Tectonophysics, 95, 133-156. 

Reches, Z. and J. H. Dieterich, 1983, Faulting of rocks in three dimensional strain fields, I. Failure of rocks in polyaxial, servo-control experiments, Tectonophysics, 95, 11-132. 

Aydin, A. and Z. Reches, 1982, Number and orientation of fault sets in the field and in experiments, Geology, 10, 107-112. 

Reches, Z., D.F. Hoexter and F. Hirsch, 1981, The structure of a monocline in the Syrian Arc system, Middle East-surface and subsurface analysis, J. Petroleum Geol., 3, 413-425. 

Reches, Z. and D. F. Hoexter, 1981, Holocene seismic and tectonic activity in the Dead Sea area, Tectonophysics, 80, 235-254. 

Reches, Z., 1979, Deformation of a foliated medium, Tectonophysics., 57, 119-129. 

Reches, Z., 1978, Analysis of faulting in three dimensional strain field, Tectonophysics, 47, 109-129. 

Reches, Z. and A. M. Johnson, 1978, The development of monoclines, Part II: Mechanical analysis of monoclines. in Laramide Folding Associated with Basement Block Faulting in the Rocky Mountains Region, edited by V. Matthews, Geol. Soc. Am. Mem. 151, 278-311. 

Reches, Z., 1978, The development of monoclines,Part I: Structure of the Palisades Creek branch of the east Kaibab monocline, Grand Canyon, Arizona, in Laramide Folding Associated with Basement Block Faulting in the Rocky Mountain Region, edited by V. Matthews, Geol. Soc. Am. Mem.151, 235-278. 

Reches, Z. and A. M. Johnson, 1976, A theory of concentric, kink, and sinusoidal folding and of monoclinal flexuring of compressible elastic multilayers, VI. Asymmetric folding and monoclinal kinking, Tectonophysics, 35, 295-334. 

Reches, Z., 1976, Analysis of joints in two monoclines in Israel, Geol. Soc. Am. Bull., 8,-1662. 

Slip nucleation during earthquakes is apparently analogous to rupture nucleation within an intact rock sample subjected to triaxial loading. The observations indicate that both these nucleation processes initiate within a relatively small volume and in both the slip propagates unstably along a quasi-planar surface. In both processes a single, pre-existing, shear fracture cannot nucleate the large-scale slip, and in both a "process zone" that includes several interacting fractures in a small volume are required to initiate the unstable slip. Both processes require rupture of intact rocks, generate complex fracture geometry, and are associated with intense energy-release-rate during slip. Recent observations and analyses are used to correlate rupture nucleation in laboratory tests with nucleation events of large earthquakes. It is proposed that earthquake nucleation occurs by the interaction among multiple fractures within a small volume that develops into unstable yielding of the healed fault zone. Keywords: earthquake, nucleation, instability, friction, rock mechanics

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Somefeatures odeformation accompanying the 1989 Loma Prieta earthquake resemble that associated with earthquakes along deep-seated reverse faults. These featinclude ground breakage, surfacedeformation, aftershock distribution, and a component of reverse slip deduced from geodetic and strong ground motion data. To explore these deformational features of the earthquake, we derive an analytical model for the deformation of a layered sequence due to slip along a deep-seated fault. Our model includes horizontal elastic layers, using configurations withas many as nine layers of different shear moduli. We applied this layered model to the Loma Prieta region and found that the better solutions are for five-layer sequences in which the shear moduli of the layers increase downward. The model predicts the distribution of aftershocks in the upper 5 km better than a model with uniform rheology. The model also accurately predicts the location of the horizontal extension zone in the Summit Road area and the horizontal-compression zone in the northeastern foothills of the Santa Cruz Mountains.

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The bending of lines at the proximity of faults, known as fault-drag, is examined here by analytical and numerical (finite-elements) models. Frequently, the bent lines are convex toward the direction of the fault motion, and this convexity is known as "normal-drag", whereas an inverted sense of convexity is known as "reverse-drag". We first analyze the slip along a short fault embedded in a large elastic or elastic-plastic plate. The analysis indicates that reverse-drag is the expected drag along the short fault, and that the normal-drag reflects continuous deformation which preceded the faulting. Models with faults of high friction coefficient display smaller drag than frictionless faults; this suggests that the drag intensity is not simply related to the frictional resistance. We also model the drag along a normal fault with curved, "anti-listric" surface embedded in an elastic-plastic medium; this model also indicates that the reverse-drag is the prevailing one. The predictions of the present models agree well with previous experimental results of slip along short faults in wax and plasticene samples. Finally, we show that the normal-drag observed in association with long faults reflects prefaulting deformation which is concentrated within a narrow shear zone.

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We analyze the cycle of great earthquakes along the San Andreas fault with a finite element numerical model of deformation in a crust with a nonlinear viscoelastic rheology. The viscous component of deformation has an effective viscosity that depends exponentially on the inverse absolute temperature and nonlinearly on the shear stress; the elastic deformation is linear. Crustal thickness and temperature are constrained by seismic and heat flow data for California. The models are for anti-plane strain in a 25-km-thick crustal layer having a very long, vertical strike- slip fault; the crustal block extends 250 km to either side of the fault. During the earthquake cycle that lasts 160 years, a constant plate velocity Vp/2=17.5 mm/yr is applied to the base of the crust and to the vertical end of the crustal block 250 km away from the fault. The upper half of the fault is locked during the interseismic period, while its lower half slips at the constant plate velocity. The locked part of the fault is moved abruptly 2.8 m every 160 yr to simulate great earthquakes. The results are sensitive to crustal rheology. Models with quartzite-like rheology display profound transient stages in the velocity, displacement and stress fields. The predicted transient zone extends about 3-4 times the crustal thickness on each side of the fault, significantly wider than the zone of deformation in elastic models. Models with diabase-like rheology behave similarly to elastic models and exhibit no transient stages. The model predictions are compared with geodetic observations of fault-parallel velocities in northern and central California and local rates of shear strain along the San Andreas fault. The observations are best fit by models which are 10 to 100 times less viscous than a quartzite-like rheology. Since the lower crust in California is composed of intermediate to mafic rocks, then the present result suggests that the in-situ viscosity of the crustal rock is orders of magnitude less the rock viscosity determined in the laboratory.<br)

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We present a model for the nucleation and growth of faults in intact brittle rocks. The model is based on recent experiments that utilize acoustic emission events to monitor faulting processes in Westerly granite. In these experiments a fault initiated at one site without significant preceding damage. The fault propagated in its own plane with a leading zone of intense microcracking. We propose here that faults in granites nucleate and propagate by the interaction of tensile microcracks in the following style. During early loading tensile microcracking occurs randomly, with no significant crack interaction, and with no relation to the location or inclination of the future fault. As the load reaches the ultimate strength, nucleation initiates when a few tensile microcracks interact and enhance the dilation of each other. They create a process zone that is a region with closely spaced microcracks. In highly loaded rock, the stress field associated with microcrack dilation forces crack interaction to spread in an unstable manner and recursive geometry. Thus the process zone propagates unstably into the intact rock. As the process zone lengthens its central part yields by shear and a fault nucleus forms. The fault nucleus grows in the wake of the propagating process zone. The stress fields associated with shear along the fault further enhances the microcrack dilation in the process zone. The analysis shows that faultsprin their own plane, making an angle of 20ø-30ø with the maximum compression axis. This model provides a physical basis to "internal friction", the empirical parameter of the Coulomb criterion.
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The strength and elastic properties of three sedimentary rocks were measured with a four- point beam device. The device was placed inside a pressure vessel and the beam samples were deformed by combined application of bending moment and confining pressure. The tensile and compressive stresses within the beams were determined from the measured loads and the axial strains at the top and bottom of the beam; for the stress calculations we used the formulation of Yokoyama (1988). The experiments were conducted with Tennessee sandstone (8 tests), Indiana limestone (8 tests), and Berea sandstone (4 tests). The compressive Young modulus for Tennessee sandstone ranges from ÷ 19,000 MPa in tests without confinement t40,000 MPa for a test under 50 MPa confining pressure. The compressive Young modulus is 26,600 MPa to 34,900 MPa for Indiana limestone, and 10,000 MPa to 27,000 MPa for Berea sandstone (with some dependence on the confining pressure). The tensile Young modulus is nonlinear and best represented by st = A etB, where st , et are the tensile stress and tensile strain anA, B are co. ranges from 0.56 for tests without confinement to 0.85-0.9 for tests with confinement of 10 MPa or more. The tensile strength depeonly slightly on the confining pressuand it is -8.8 ñ 3.1 MPa for Tennessee sandstone, -5.1 ñ 2.5 MPa for Indiana limestone and -6.9 ñ 2.4 MPa for Berea sandstone (tensile stress is negative). The yileding envelope for the tensile regime appears in good agreement with Griffith's envelope .
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The coefficient of friction of small faults in the field are estimated here by stress inversion of fault slip data. The small faults that were measured in Israel and the Grand Canyon, Arizona, are considered as representing natural friction experiments. The stresses associated with the faulting are determined by a stress inversion method which incorporates the Coulomb failure criterion [Reches, 1987]. The coefficients of friction determined for 27 fault clusters in limestone, sandstone, and basalt range from 0.0 to 1.3 with mean value of 0.58 ñ 0.37. These values are in general agreement with the friction of 0.6-0.85 determined from laboratory experiments. The magnitudes of the calculated principal stresses are compared with in situ stress measurements in similar tectonic environments.
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