Geodynamic pattern of the West Bohemia region based on permanent GPS measurements   总被引：2，自引：2，他引：0  

Vladimir Schenk  Zdeňka Schenkova  Zuzana Jechumtálová 《Studia Geophysica et Geodaetica》2009,53(3):329-341

In West Bohemia in the period of 2003–2005 five permanent GPS stations were established to detect local movement trends. Their mutual position changes were determined from time series of GPS observations and were associated with seismic, gravity, and geo-scientific data related to the geodynamics of the West Bohemian region. Knowledge of local physical processes based on spatial and time earthquake occurrences, focal mechanisms of main events, stress and strain fields set up a tool for recent seismotectonic analyses. The permanent GPS measurements bring independent effective phenomenon, direct monitoring of site movements. The movements detected by our GPS stations evidenced WSW-ENE extension with subsiding trends in the western part of the Cheb Basin and the Smrčiny Mts. Besides, there were monitored dextral movements along the Mariánské Lázně tectonic fault zone (MLF). A comparison of results with previous data formed a presumption that an antithetic stress pattern has to exist inside the inner part of the MLF tectonic zone. This antithetic stress can explain the coexistence of dextral and sinistral movements on individual tectonic elements in the West Bohemian area.  相似文献   

Suspended particulate matter and vertical fluxes of sedimentary material in bays of the Murmansk (Barents Sea) and Karelian (White Sea) coasts     

M.?V.?MityaevEmail author  M.?V.?Gerasimova  V.?Ja.?Berger 《Oceanology》2017,57(2):306-314

Synchronous measurement of the total suspended organic and mineral particulate matter, together with vertical sedimentary matter flux, carried out in various areas of Yarnyschnaya Inlet (Murmansk coast of the Barents Sea) and Chupa Inlet (Karelian coast of the White Sea) revealed that the seston organic component plays no part in sedimentation, being almost completely utilized in the water column, while the majority of mineral matter is transported out of the bay. The total amount of suspended matter and its components in the water column is estimated, as well as the total flux of sedimentary matter to the bottom of Chupa and Yarnyschnaya inlets.  相似文献   

Expanding shells in low and high density environments     

Jan Palouš  Soňa Ehlerová  Richard Wüunsch 《Astrophysics and Space Science》2003,284(2):873-876

The gravitational instability of expanding shells evolving in a homogeneous and static medium is discussed. In the low density environment (n = 1 cm^-3), the fragmentation starts in shells with diameters of a few 100 pc and fragment masses are in the range of 5 × 10³ - 10⁶ M _⊙. In the high density environment (n = 10⁵ - 10⁷ cm^-3), shells fragment at diameters of pc producing clumps of stellar masses. The mass spectrum in both environments is approximated by a power law dN/dm ∼ m ^-2.3. This is close to the slope of the stellar IMF. To reproduce the observed mass spectrum of clouds (the spectral index close to ∼ -2.0) we have to assume, that the cloud formation time is independent of the cloud size, similarly to the Jeans unstable medium. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

On separation of major meteoroid streams from the sporadic background     

V. Porubčan  J. Svoreň  L. Neslušan 《Earth, Moon, and Planets》1995,68(1-3):471-478

The paper deals with a search for chosen photographic meteoroid streams compiled from the IAU Meteor Data Center Lund catalogue from which less than 2% of the orbits had to be removed due to internal inconsistency among the orbit parameters. Additional 35 orbits were removed due to extremely high hyperbolic velocities. The final set consists of 3411 orbits. Members of the Quadrantids, Lyrids, Perseids and Geminids were searched for, firstly, by a stream-search procedure utilizing the Southworth-HawkinsD-criterion. This choice, as a rule, represents the most abundant filament of the stream. Secondly, rate distribution histograms ofD were divided into region of shower meteors and region of sporadic background meteors. The searched database with a relatively low abundance of sporadic meteors in the analyzed periods simplified this choice, and followingly, fitting the obtained values by means of power and exponential functions, the limitingD _s for particular showers were derived. The derivedD _s appears as the optimum value, as for higherD, the number of sporadic meteors included in the stream sample increases more rapidly than the number of additional shower meteors, and for smallerD, the number of shower meteors decreases quicker than the number of omitted sporadic meteors. The following counts of shower meteorsN and limitingD _s were found: Quadrantids (39, 0.22), Lyrids (11, 0.15), Perseids (595, 0.53) and Geminids (224, 0.32). Efficiency of the procedure was tested comparing the number of sporadic meteors in the region of radiant area and the neighbouring regions of the same size.  相似文献   

Relativistic theory of the Moon's motion     

A. M. Finkelstein  V. Ja. Kreinovich 《Celestial Mechanics and Dynamical Astronomy》1976,13(2):151-176

Relativistic corrections for the elements and coordinates of the Moon have been obtained in the framework of the PPN-formalism. The influence of the coordinate conditions on the observational effects was studied.  相似文献   

First finds of Permian conodonts in eastern Iran and once again on the Guadalupian series base in Permian sections of the Tethyan realm     

E. Ja. Leven  A. N. Reimers  H. W. Kozur 《Stratigraphy and Geological Correlation》2007,15(1):57-66

Conodonts found for the first time in eastern Iran (the Bage-Vang section) are characterized. Beds with conodonts also yield fusulinids that is suitable for refining correlation of conodont and fusulinid zonations. Stratigraphic ranges of different conodont species in the Bage-Vang section are correlated with those in the Luodian section (South China), where conodonts are also accompanied by fusulinids. As a result, some previous inferences concerning position of the Guadalupian Series base in the Tethyan sections are refined.  相似文献   

M 2 amphidrome in the northeast pacific     

Ja mes Irish  Walter Munk  Frank Snodgrass 《地球物理与天体物理流体动力学》2013,107(1):355-360

Abstract

A previously proposed amphidrome between San Diego and Hawaii is confirmed by offshore measurements of tides across the amphidrome, showing opposite phases and opposite sense of current rotation.  相似文献   

The Method of Selection of Major-Shower Meteors Revisited     

L. Neslušan  J. Svoreň  V. Porubčan 《Earth, Moon, and Planets》2013,110(1-2):41-66

We apply so-called break-point method to select the dense cores of 10 major meteor showers from the photographic, video, and radio-meteor databases. The major showers can well be selected from photographic and video data, in a lesser degree from radio data. The obtained mean characteristics of Quadrantids, Lyrids, η-Aquarids, α-Capricornids, δ-Aquarids N, δ-Aquarids S, Perseids, Orionids, Leonids, and Geminids are presented. A test to indicate the existence of a suspected shower in radio database is suggested.  相似文献   

Origin of higher fusulinids of the order eoschwagerinida Minato et Honjo, 1966     

E. Ja. Leven 《Stratigraphy and Geological Correlation》2010,18(3):290-297

As is argued in this work, genera Zarodella Sosnina, 1981, and Grovesella Davydov et Arefifard, 2007, could be ancestors of the genus Pamirina Leven, 1970, which gave birth to all higher fusulinids. Two former genera similar to each other are distinguished conventionally to a certain extent in a large flexible taxon of small primitive polymorphic fusulinids close to the Bashkirian genera Eostaffella, Plectostaffella, and Semistaffella. Without essential changes, this taxon existed for a long time from the Bashkirian Age of the Late Carboniferous to the Bolorian Age of the Permian. The genus Pamirina branched off that taxon in the Yakhtashian Age. Along with Zarodella and Grovesella, the genus Pamirina is attributed to the order Ozawainellida.  相似文献   

Geochemistry of the Drahotín and Mutěnín intrusions, West Bohemian shear zone, Bohemian massif: contrasting evolution of mantle-derived melts     

Lukáš Ackerman  Martina Krňanská  Wolfgang Siebel  Ladislav Strnad 《Mineralogy and Petrology》2010,99(3-4):185-199

In western Bohemia, the Drahotín (gabbro-diorite) and Mutěnín (gabbronorite-diorite-syenite) intrusions show different origins and patterns of geochemical evolution. Parental magmas of the Drahotín intrusion were derived predominantly from enriched mantle sources, and the melts have undergone a significant degree of assimilation-fractional crystallization (AFC) during their ascent and/or emplacement into the crust. In contrast, the compositional variation of the complex Mutěnín intrusion cannot be explained by simple AFC processes, but more likely reflects the involvement of several parental magmas. The gabbronorite was derived from a depleted mantle source, whereas the diorite/syenite stem from a mixed mantle-crust reservoir. The contrasting evolution of the Drahotín and Mutěnín intrusions may be due to their melt derivation and magma emplacement under different tectonothermal regimes at different times.  相似文献