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111.
Peak acceleration attenuation relations for horizontal and vertical components are presented for the Dinarides region, based on 145 3-component accelerograms related to 46 earthquakes with local magnitudes of 4.5 or greater and with epicentral distances of less than 200 km as recorded on 39 recording sites in the greater Dinarides region. The attenuation functions were obtained by two-stage stratified regression on the local magnitude and epicentral distance as independent variables. The predicted peak acceleration values within the distance range covered by the data are comparable to the ones obtained for stiff-soil or rock sites when selected reference relations are used. The rather large average residuals are caused mostly by the lack of information on local site conditions and by the use of epicentral distance instead of fault distance. 相似文献
112.
113.
Ivan Kimák Karel Kudela P. V. Vakulov Reviewer S. Fischer 《Studia Geophysica et Geodaetica》1982,26(2):207-211
Summary Data obtained from apparatus detecting energetic particles on low altitude polar orbiting satellite Intercosmos-13 show enhancement of quiasitrapped proton flux (Ep=1–11 MeV) near L=4 in comparison with both and lower L. This phenomenon persists during intervals with low level of geomagnetic activity. Possibility of influence of false pulses on the result is discussed. 相似文献
114.
Erik W. Grafarend Ivan I. Mueller Haim B. Papo Burghard Richter 《Journal of Geodesy》1979,53(3):195-213
Modern high accuracy measurements of the non-rigid earth are to be referred to four-dimensional, i.e., time- and space-dependent
reference frames. Geodynamic phenomena derived from these measurements are to be described in a terrestrial reference frame
in which both space- and time-like variations can be monitored. Existing conventional terrestrial reference frames (e.g. CIO,
BIH) are no longer suitable for such purposes.
The ultimate goal of this study is the establishment of a reference frame, moving with the earth in some average sense, in
which the geometric and dynamic behavior of the earth can be monitored, and whose motion with respect to inertial space can
also be determined.
The study is conducted in several parts. In the first part problems related to reference directions are investigated, while
subsequent parts deal with positions, i.e., with reference origins and scale. Only the first part is treated in this paper.
The approach is based on the fact that reference directions at an observation point on the earth surface are defined by fundamental
vectors (gravity, earth rotation, etc.), both space and time variant. These reference directions are interrelated by angular
parameters, also derived from the fundamental vectors. The interrelationships between these space- and time-variant angular
parameters are illustrated in a commutative diagram, tower of triads, which makes the derivation of the various relationships
convenient. In order to determine the above parameters from observations using least squares techniques, a model tower of
triads is also presented to allow the formation of linear observation equations. Although the model tower is also space and
time variant, its variations are described by adopted parameters representing our current knowledge of the earth. 相似文献
115.
Vlastislav Červený Ivan Pšenčík Reviewer J. Vaněk 《Studia Geophysica et Geodaetica》1972,16(4):356-366
Summary A method for computing certain types of diffracted rays and corresponding travel-time curves in laterally inhomogeneous media with slightly curved interfaces is suggested. Numerical examples are presented.Dedicated to Academician Alois Zátopek on His 65th Birthday 相似文献
116.
The determination of baseline lengths from certain space techniques is based on the derived coordinates of the terminal stations.
As such, the estimated baselines are susceptible to systematic errors that affect the relative coordinates. One source of
error is in the set of parameters which describes the continuously changing relative orientation of the Conventional Terrestrial
(CTS) and Inertial (CIS) Reference frames. Due to these errors, the coordinates of each terminal station may in fact refer
to a slightly different coordinate svstem, and, therefore, when used for computing the length between the stations, errors
will result. The expected magnitudes of such errors and their possible presence in current solutions are investigated.
In conclusion, we find that the present level of accuracy and stability of the available parameters connecting the CTS and
CIS (e.g., the ERP series) is unsatisfactory for centimeter level baseline length determinations. The available options are
either the use of strictly simultaneous SLR data sets (similar to the VLBI data sets) or the improvement of the parameters
connecting the CTS and the CIS. The first long-range step in the latter direction is the support of the IAG/IAU Joint Working
Group COTES proposal [CSTG Bulletin, 1982], endorsed by both the IAG and IAU in various resolutions [IAU, 1983; IAG, 1982].
Presented at the Annual Fall Meeting of the American Geophysical Union, San Francisco, December 7–15, 1982, and at the Fifth
Annual NASA Geodynamics Program Conference and Crustal Dynamics Project Review, Washington, D.C., January 24–28, 1983. 相似文献
117.
This work presents results from numerical modelling studies on the hydrodynamics and sediments and passive particles transport properties in Ria de Aveiro, a shallow lagoon located on the Portuguese Northwest Atlantic coast. The hydrodynamic of the lagoon was systematically studied, from both the Eulerian and Lagragian point of view, in order to understand the overall circulation in the lagoon, characterize the dynamics of its different channels and assess the transport of suspended cohesive sediments.Responsible Editor: Hans Burchard 相似文献
118.
119.
120.
Ivan J. Townshend 《GeoJournal》2006,66(1-2):103-120
The privatization of urban space, as represented in the trend towards a wide variety of common interest developments and increasing
prevalence of gated communities, is an international phenomenon. Recent research has not systematically explored the ways
in which these types of developments are collectively re-shaping the public and private realms of the city at large. This
empirical study of community areas in a Canadian city describes a number of historical private neighbourhood development trends
and their convergence in space and time. Based on the empirical generalizations, a conceptual model is developed to illustrate
how the trends may have combined to produce a new geography or ecology of space privatization within the city, one in which
the older public city is being circumscribed and bounded by new territories of multi-tiered privatization. 相似文献