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Salvi S. Quattrocchi F. Brunori C. A. Doumaz F. Angelone M. Billi A. Buongiorno F. Funiciello R. Guerra M. Mele G. Pizzino L. Salvini F. 《Natural Hazards》1999,20(2-3):255-278
A priority task for correct environmental planningis to evaluate Natural Hazards, especially inhighly populated areas. In particular, thoroughinvestigations based on different Earth Sciencetechniques must be addressed for the Seismic HazardAssessment (SHA) in tectonically active areas. Notonly the management but also the multidisciplinaryanalysis of all the SHA-related data sets is bestperformed using a Geographic Information System. In this paper we show how a research-oriented GIS isbuilt and used in a practical case. The GeochemicalGeographic Information System (G2IS) wasdeveloped and applied to the Gargano promontory(southern Italy) in the framework of an EC researchproject, the Geochemical Seismic Zonation (GSZ)Project. This multidisciplinary – multiscalingpowerful tool is described in its structure, updatingprocedures and manipulation techniques. Preliminaryresults are presented on the detection of geochemically active fault zones and theircorrelation with remote sensing data and otherevidences of seismogenic structures. 相似文献
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Field data on Cenozoic faults and the McMurdo dyke arrays in the Reeves Glacier–Mawson Glacier area, Victoria Land, Antarctica, allow us to support noncoaxial transtensional tectonics along the N–S-trending western shoulder of the Ross Sea. Dyke injection within a crustal-scale right-lateral strike-slip shear zone is testified by magma filled, tension gash-like arrangements within some master fault zones, and by the left-stepping arrangements of dykes in the intrafault zones. The noncoaxiality of deformation is shown by the re-activation of many dyke walls as right-lateral strike-slip faults. This suggests an increase in the strike-slip component over time along the western shoulder of the Ross Sea. Our data support the relevance of transtensional to strike-slip tectonics for triggering melting and controlling the geometry and modes of magma emplacement. 相似文献
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Fault tip regions, relay ramps and accommodation zones in between major segments of extensional fault systems provide zones of additional structural and stratigraphic complexities and also significantly affect their hydraulic behaviour. The great interest for both academic and industrial purposes encouraged specific studies of fault tip regions that, in some cases, produced controversial results. We approached the study of fault tip regions by integrating structural, AMS and stratigraphic analyses of the tip of an extensional growth fault system in the Tarquinia basin, on the Tyrrhenian side of the Northern Apennines. Detailed structural mapping indicates the occurrence of systematic relationships between the orientation of the main subsidiary fault zones, the orientation and position of the two main joint sets developed in the fault damage zones, and the overprinting relationships between the two main joint sets themselves. Microstructural analysis of fault core rocks indicates a progression of deformation from soft-sediment to brittle conditions. The AMS study supports the evolution of deformation under a constantly oriented stress field. By combining this multidisciplinary information we propose an evolutionary model for the tip of the extensional growth fault system that accounts for the progressively changing sediment rheological properties, and for the time dependent subsidiary deformation pattern by invoking the interplay between the regional stress field and the local, kinematically-derived one by fault activity. We also speculate on the overall implications for fluid flow of the proposed evolutionary model. 相似文献
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The Bonarelli Horizon is an important regional marker level in the Umbria-Marche Apennines. It is characterized by consisting of black bituminous shales that yield a distinctive radiolarian fauna. Black shales referable to the Bonarelli Horizon are also present in the Southern Alps. The horizon is of uniform lithology and contains radiolarian assemblages of late Cenomanian-early Turonian age throughout both the Umbria-Marche Apennines and Southern Alps. Several new radiolarian taxa have been recognised and described from the Bonarelli Horizon of both areas. Two new species are defined in this paper, namelySethocapsa bossoensisandXitus picenus. 相似文献
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Disjunctive, spaced solution cleavage in carbonate rocks is genetically associated with the propagation of the left-lateral, strike-slip Mattinata Fault in the Gargano Promontory, Italy. Typical cleavage development is restricted within the 200–300-m wide fault zone, which is bounded by virtually unfractured wall rocks. The cleavage consists of sub-parallel solution surfaces, which are often reactivated as sheared solution planes. Geometrical and kinematic relationships exist between the fault and the associated cleavage planes, thus: (1) cleavage–fault intersection lines lie parallel to the fault and the sheared cleavage rotational axes and (2) the cleavage–fault angle is almost constantly equal to 40°. A model for the development of the Mattinata Fault is proposed in which the cleavage surfaces are interpreted as fault-propagation deformations. Cleavage nucleates as solution planes at the front of the advancing fault as the result of stress concentration in this region. Two distinct, time-sequential processes are shown to operate during the fault propagation: (1) typical millimetre- to centimetre-spaced solution surfaces form in the distal tip zone of the advancing fault plane; (2) as the tip advances, the fault plane breaks through the cleavage as minor shear displacements reactivate some of these nascent surfaces. These observations may prove useful in understanding mechanisms for fault-controlled enhanced/reduced permeability and fluid pathways. 相似文献
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A fundamental yet still unresolved puzzle provided by cataclasis is whether particle size reduction mostly progresses through time by the same fragmentation mechanism or not. Available field, laboratory and numerical modelling results on the evolution of cataclastic rocks are still controversial. The evidence that cataclastic rocks exert a primary control on the frictional strength, stability, seismic velocity and permeability properties of fault zones encourages further research on cataclasis. Here, we report data on particle shape from natural cataclastic rocks in poorly layered carbonates in the Apulian foreland of the Southern Apennines of Italy. Particle shape analyses show that particle angularity decreases with increasing size and, for a given size class, it decreases with increasing fractal dimension of the particle size distribution. These results offer support to the temporally and spatially variable nature of rock comminution. 相似文献
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ABSTRACT Laboratory experiments on rock faulting show that processes of particle comminution in fault rocks are influenced by several parameters, including fault strike and normal stress across faults. In nature, normal stress across faults increases with increasing transpressional strike of faults. Accordingly, different structural fabrics and particle size distributions are expected for cataclastic rocks that have developed along faults with different transpressional orientations and comparable displacements within regional-scale strike-slip fault zones. Adjacent bands of cataclastic gouge and breccia were analysed from four small-scale fault zones. All have comparable displacements and very similar protolith (i.e. shallow-water limestone), structure, kinematics, size, and tectonic environment, but different transpressional strikes within the regional-scale left-lateral Mattinata strike-slip fault, Italy. An inverse linear relationship is found between fault transpressional angles and fractal dimensions of particle size distributions from cataclastic rock samples. 相似文献
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Natural Hazards - Forests are always dangerous to fire in China’s forested regions, and forest fire hazard has long been a serious issue in China. Zhejiang province is one of the key forest... 相似文献
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DanteSalvini 《地球空间信息科学学报》2002,5(1):18-21
One type of aerial cableway consists of a continuous cable,which works at the same time as carrying cable and drawing cable.This kind of cableway is supported by many towers,which divide the total length in linear sections.even small deviations from the planed layout can increase the strain of the cable and the danger of derailments.The deviations of the position of the towers from the planed layout are due to local sliding or sinking of the foundation or other mechanical movements.Up to now the axis of the cableways were periodically measured by traditional methods. The goal of this project is to demonstrate the possibility of measuring the axis of a cableway with GPS techniques,while the cable is moving.The results show that the proposed measuring device provides precise results in a simple and reliable way. 相似文献