排序方式： 共有131条查询结果，搜索用时 593 毫秒
41.
Bulletin of Earthquake Engineering - A correction to this paper has been published: https://doi.org/10.1007/s10518-021-01105-0 相似文献
42.
Mirko Carlini Alessandro Chelli Roberto Francese Serena Giacomelli Massimo Giorgi Andrea Quagliarini Andrea Carpena Claudio Tellini 《Landslides》2018,15(2):283-296
This paper investigates the role played by geomorphological and tectonic processes affecting a portion of an active mountain belt in causing the occurrence of different types of landslides developed in flysch bedrock. The adopted multidisciplinary approach (geomorphology, geology and geophysics) allowed to recognize in a portion of the Northern Apennines of Italy different types of landslides that developed in response to slope dynamics, in turn dependent on broader regional-scale tectonic processes. Sedimentary bed attitude, local tectonic discontinuities and lithology only partially influenced the type of landslides, which have been deeply affected by the activity of regional-scale antiform that controlled the hillslope geomorphic evolution in different ways. The growth of this structure and the tilting of its forelimb produced gently dipping slopes that approached the threshold angle that can cause the occurrence of (mainly) translational rockslides. Conversely, high-angle normal faulting parallel to the antiform axis (related to a later stage of activity of the antiform itself) strongly controlled the stream network evolution and caused the watercourses to deeply incise portions of their valleys. This incision produced younger steep valley slopes and caused the development of complex landslides (roto-translational slides-earth/debris flow). The results of the integrated study presented in this paper allowed to distinguish two main types of landslides whose development reflects the events that led to the geomorphological and geological evolution of the area. In this perspective, within the study area, landslides can be regarded and used as indicators of broader-scale recent tectonic processes. 相似文献
43.
44.
Temperature, salinity, meltwater percentage, water column stability, dissolved oxygen and nutrients were measured in seawater samples collected at three fixed depths (0, 20, 100 m) in 104 stations located in three different areas of the Ross Sea (Antarctica), during four Italian Antarctic surveys carried out between 1998 and 2006. Nutrient data were used to quantify the nutrient removal, which appears particularly high in 2006, especially in polynya area. The N:P and Si:N disappearance ratios were studied to estimate the dominant phytoplanktonic community. No significant differences in the nutrient drawdown ratio were observed, in fact the N:P ratio was always below the Redfield standard ratio. 相似文献
45.
This paper documents the occurrence of large amounts of talc within a continental normal fault. The talc-in reaction is deformation-enhanced
and occurs by the interaction between dolostones and silica-rich hydrothermal fluids. In the high-strain, foliated fault core,
talc forms an interconnected network of oriented (001) lamellae, 200–300 nm thick, locally associated with minor tremolite
fibres, up to 300 nm in diameter. The talc structure is affected by several strain-induced defects, among which (001) interlayer
delamination that produces talc “sublamellae” down to 10–30 nm thick. Micro/nanostructural observations definitely point to
a predominant deformation mechanism of (001) frictional sliding, further enhanced by pervasive delamination that gives rise
to an almost infinite number of possible sliding surfaces. These effects have fundamental implications in fault mechanics,
resulting in significant fault weakening. 相似文献
46.
47.
Bruno Cataletto Enrico Feoli Serena Fonda Umani Marina Monti Irene Pecchiar 《Marine Ecology》1996,17(1-3):291-307
Abstract. Multivariate techniques (cluster analysis and Principal Component Analysis) applied on phytoplankton data collected in June, July, August, and September 1990, 1991, 1992, and 1993 in the Gulf of Trieste (Northern Adriatic Sea) highlighted a clear temporal pattern from 1990 to 1993. In the summer of 1991, phytoplankton communities showed a dramatic increase in the dinoflagellatddiatom ratio. In particular, during June and July 1991 only few specimens of diatoms ( Cylindrorhecu closreriurn. Probosciu alata, Nirzschio longissimu , and Nitzschiu spp.) were collected; this confirmed the diatom scarcity in the phytoplankton communities before and during the appearance of large mucous aggregates (mucilage) in July 1991 in the Gulf of Trieste. The differences observed between the structure of the phytoplankton communities inside the aggregates and in the ambient waters suggested two hypotheses: 1) the aggregates were not produced in the gulf, but were carried ints the gulf by the eastern bordering current; 2) the aggregates were produced by a few, scarce species with a high exudate production that are capable of quickly reaching a high reproductive rate within the aggregates. 相似文献
48.
H. R. A. Jones S. Viti J. Tennyson B. Barber G. Harris J. C. Pickering R. Blackwell‐Whitehead J.‐P. Champion F. Allard P. H. Hauschildt U. G. Jorgensen P. Ehrenfreund E. Stachowska H.‐G. Ludwig E. L. MartÍn Ya. Pavlenko Yu. Lyubchik R. L. Kurucz 《Astronomische Nachrichten》2005,326(10):920-924
A full understanding of the properties of substellar objects is one of the major challenges facing astrophysics. Since their discovery in 1995, hundreds of brown dwarfs and extrasolar planets have been discovered. While these discoveries have enabled important comparisons with theory, observational progress has been much more rapid than the theoretical understanding of cool atmospheres. The reliable determination of mass, abundances, gravities and temperatures is not yet possible. The key problem is that substellar objects emit their observable radiation in the infrared region of the spectrum where our knowledge of atomic, molecular and line broadening data is poor. Here we report on the status of our PoSSO (Physics of SubStellar Objects) project. In order to understand brown dwarfs and extrasolar planets increasing more like those in our solar system, we are studying a wide range of processes. Here we give an update on the project and sketch an outline of atoms, molecules and processes requiring study. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
49.
50.