The inception and growth of the active Carpino-Le Piane Basin Fault System (CLPBFS; central-southern Apennines, Italy) was analysed with respect to the neighbouring Isernia and Surrounding (ISFS) and Boiano Basin (BBFS) extensional Fault Systems. 39Ar–40Ar dating showed that the BBFS was already active 649 ± 21 ka bp and that the ISFS was active at least 476 ±10 ka bp , whereas the activity of the CLPBFS started certainly later than 253 ± 22 ka bp , and very probably as recently as <28 ka bp . These ages, combined with structural data (geometry and kinematics of the fault systems), indicate that the inception and development of the CLPBFS could be strictly related to the stress changes caused by earthquakes occurring on the BBFS. 相似文献
This paper deals with Hamiltonian perturbation theory for systems which, like Euler-Poinsot (the rigid body with a fixed point and no torques), are degenerate and do not possess a global system of action-angle coordinates. It turns out that the usual methods of perturbation theory, which are essentially local being based on the construction of normal forms within the domain of a local coordinate system, are not immediately usable to study perturbations of these systems, since degeneracy makes impossible to control that the system does not fall into a singularity of the coordinates. To overcome this difficulty, we develop a global formulation of Hamiltonian perturbation theory, in which the normal forms are globally defined on the phase space manifold. The key for this study lies in the geometry of the fibration by the invariant tori of an integrable degenerate Hamiltonian system, which is described by some generalizations of the Liouville-Arnol'd theorem and is reviewed in the paper. As an application, we provide a global formulation of Nekhoroshev's theorem on the stability for exponentially long times. 相似文献
A combination of empirical and physically based hydrological models has been used to analyze historical data on rainfall and debris-flow occurrence in western Campania, to examine the correlation between rainfall and debris-flow events.
Rainfall data from major storms recorded in recent decades in western Campania were compiled, including daily series from several rain gauges located inside landslide areas, supplemented by hourly rainfall data from some of the principal storms.
A two-phase approach is proposed. During phase 1, soil moisture levels have been modelled as the hydrological balance between precipitation and evapotranspiration, on a daily scale, using the method of Thornthwaite [Geograph. Rev. 38 (1948) 55].
Phase 2 is related to the accumulation of surplus moisture from intense rainfall, leading to the development of positive pore pressures. These interactions take place on an hourly time scale by the “leaky barrel” (LB) model described by Wilson and Wiezoreck [Env. Eng. Geoscience, 1 (1995) 11]. In combination with hourly rainfall records, the LB model has been used to compare hydrological effects of different storms. The critical level of retained rain water has been fixed by the timing of debris-flow activity, related to recorded storm events.
New rainfall intensity–duration thresholds for debris-flow initiation in western Campania are proposed. These thresholds are related to individual rain gauge and assume a previously satisfied field capacity condition. The new thresholds are somewhat higher than those plotted by previous authors, but are thought to be more accurate and thus need less conservatism. 相似文献
This paper deals with the effects of thermal stresses on selected carbonate rocks used as dimension stones. They are Mesozoic calcareous and dolomitic rocks cropping out in Apulia (southern Italy) that, for their physico-mechanical and aesthetic properties, have always been finding a large application both as ornamental stones and as simple construction materials; their use is attested not only in Italy, in works of archaeological, historical and artistic interest too. The cause–effect relationships of thermal degradation were studied by means of an artificial accelerated ageing test, in order to provide a perspective about the decay of carbonate stones due to diurnal and seasonal temperature fluctuations, as well as thermal shocks during events of fire development. The stone samples were subjected to thermal cycles in a muffle furnace, ranging from 100 to 700 °C; after each cycle, several non-destructive and semi-destructive tests were carried out: mass and volume measurements, mercury intrusion porosimetry, sclerometer tests, ultrasonic tests, thin-section observations and determination of chromatic alterations through image analysis and Munsell charts method. In this way, the qualitative and quantitative modifications induced in fabric, physical and mechanical properties were discussed. The results highlight the fundamental role of depositional and diagenetic fabric that, together with mineralogical composition, represents the most significant discriminating factor in the response of the stone to thermal stresses. 相似文献
The Dachang mining district is the second largest producer of Sn in China and an important source of other metals. The known mineralizations can be divided into four groups: (1) cassiterite + Cu-Fe-Pb-Zn sulfides and sulfosalts, (2) Zn-Cu skarn, (3) Sb-W veins and (4) residual and placer concentrations of Sn and Fe oxides. Most orebodies are hosted by Upper Devonian calcareous, marly and quartzitic formations in spatial association with Cretaceous Yanshanian magmatites. A characteristic feature is the occurrence of stratiform, lens-shaped orebodies which appear to represent the root zone of overlying stockwork mineralizations. The metallogeny of the district may be interpreted in terms of an Upper Devonian Sn and polymetallic concentration with subsequent remobilization and, possibly, the introduction of additional elements during the late stages of the Yanshanian magmatism. 相似文献
Land subsidence severely threatens most of the coastal plains around the world where high productive industrial and agricultural activities and urban centers are concentrated. Coastal subsidence damages infrastructures and exacerbates the effect of the sea-level rise at regional scale. Although it is a well-known process, there is still much more to be improved on the monitoring, mapping and modeling of ground movements, as well as the understanding of controlling mechanisms. The International G... 相似文献