HVSR of ambient noise in Ston (Croatia): comparison with theoretical spectra and with the damage distribution after the 1996 Ston-Slano earthquake     

Marijan Herak  Ivo Allegretti  Davorka Herak  Krešimir Kuk  Vlado Kuk  Krešimir Marić  Snježana Markušić  Josip Stipčević 《Bulletin of Earthquake Engineering》2010,8(3):483-499

Horizontal-to-vertical spectral ratios (HVSR) of ambient vibrations measured in the ancient town of Ston (Croatia) on 99 locations, are shown to be well matched to the theoretical ones computed for body-waves as well as for the surface waves. This match is poorer for sites on the slopes of nearby hills. The ratios of measured peak horizontal ground acceleration during the damaging earthquake in 1996 (M _L = 6.0) and the ones obtained using empirical attenuation laws is approximately equal to the mapped value of the dynamic amplification factor determined on the basis of observed HVSR in the vicinity of the accelerometric station. The HVSR of the accelerogram is very similar to the HVSR of the ambient noise. The damage to the building stock in the old town centre caused by the earthquake series of 1996 is closely related to the estimated soil amplification and its fundamental frequency. More measurements in buildings are needed to arrive at confident conclusions about possible soil-structure resonance.  相似文献   

Rotation axes of asteroids: Results for 14 objects     

V. Zappalà  Z. Knežević 《Icarus》1984,59(3):436-455

In this paper results of determinations of the rotation axis direction (as given by ecliptic coordinates of its intersection with geocentric celestial sphere) for 14 asteroids are presented for which a sufficient number of good observations are available. The calculation is performed by using the improved amplitude-magnitude method developed by V. Zappalà, M. Di Martino, P. Farinella, and P. Paolicchi (1983, In Asteroids, Comets, Meteors, pp. 73–76). Additionally, an improvement of the method is described regarding a weighting procedure. Whenever possible, the results are compared with already existing data, coming from other methods (mainly from photometric astrometry). In general, very good agreement was found, which can be considered as strongly encouraging for further application of the adopted procedure. Some preliminary approaches for a statistical investigation are given.  相似文献   

Editor's note     

Dr. Ivan Crkvenčić 《GeoJournal》1996,38(4):379-379

  相似文献   

A model of light-curve synthesizing for dwarf novae and the analysis of the OY Car observations by application of the inverse-problem method     

Gojko Djurašević 《Astrophysics and Space Science》1996,240(2):317-329

The paper contains a model synthesizing the light curves of novae and novae-like stars, as well as of active close binaries (CB) in the phase of an intensive matter exchange between the components with accretion onto a white dwarf. The model considers the radial and azimuthal temperature distributions in the disk enabling a successful interpretation of asymmetrically deformed light curves characteristic for these systems. The analysis of the observed light curves is performed by using the inverse-problem method (Djuraevi, 1992b) adapted to this model. In the particular case the parameters for the dwarf-novaOY Car are estimated on the basis of the U and B observations (Woodet al., 1989).The synthetic light curves obtained through the inverse-problem solving, as a whole, fit the observations well which indicates that it is possible to estimate the system parameters on the basis of the model proposed here.The obtained results indicate a complex hot-spot structure approximated in the model with two components—a central part and a surrounding spot larger in size. The central hot-spot part (temperature about 10000 K is surrounded asymmetrically by the larger spot lower in temperature (about 7000 K). The radiation of the central hot spot is beamed forward by about 20°. The angular size of the hot-spot central part is about 5°, the centre longitude is 322°, whereas for the surrounding spot the size is about 33° and the longitude of the centre about 300°.For the mass ratio of the componentsq=0.102 one finds for the orbit inclination about 83°.8. The analysis shows that the disk radius is about 51% of the corresponding Roche lobe radius.Based on the U and B light curves the quiescent disk-edge temperature is estimated to about 5500 K (U), i.e. 4400 K (B). The disk-radial-temperature profile is much flatter than in the steady-state-approximation case. Beginning from the edge towards the disk centre the temperature slowly increases attaining about 7200 K (U), i.e. 5700 K (B) near the white dwarf. The differences in the solutions for the U and B light curves can be due to deviations in the disk radiation from the black-body approximation assumed in the present model. Expressed in the units of the distance between the component centres [D=1] the disk size is estimated to about 0.304 [D=1], its thickness to 0.014 [D=1], and the white-dwarf radius to about 0.02 [D=1]. The white-dwarf temperature is about 15000 K.The obtained results are in a relatively good agreement with the system parameters estimated earlier (Woodet al., 1989). This indicates that the proposed model of the system and the corresponding inverse-problem method briefly presented here are fully applicable to the analysis of active CB light curves in this evolutionary phase. Though the model given here includes a number of approximations, it enables an independent procedure in the observational-material analysis based on the light-curve synthesis and on the application of the inverse-problem method. Results obtained by applying such an independent method can also serve as a reasonable way in testing the solutions obtained by utilising the earlier approaches.  相似文献   

Gylden-Meščerskii problem     

L. M. Berković 《Celestial Mechanics and Dynamical Astronomy》1981,24(4):407-429

Classical non-stationary two-body problem, described by the equation of the form $$\ddot r = - \mu (t)\frac{r}{{r^3 }}$$ is investigated using differential equation transformation methods developed by the author. All laws of mass variation for which Gylden-Me??erskii problem is reduced to autonomous form are stated. The problem symmetry properties are investigated and reviews of integrable cases from the group point of view are made.  相似文献   

Modelled sulphur depositions over Croatia     

Z. Bencetić Klaić  S. Beširević 《Meteorology and Atmospheric Physics》1998,65(1-2):133-138

Summary A Lagrangian receptor-oriented long-range transport model has been applied in order to estimate the relative contribution of domestic, Austrian, Hungarian, Italian and Slovenian emissions to the long-term deposition of airborne sulphur in Croatia. During the November 1, 1991 to April 30, 1992 period 163.31 thousands of tonnes of sulphur were deposited over Croatia., where 90.9% originated from transboundary emission sources. Relative contribution of domestic sources was the biggest (9.1%), while Austrian contribution was the smallest (0.4%).With 1 Figure  相似文献   

The Relationship Between the Sava River Basin Annual Precipitation, its Discharge and the Large-Scale Atmospheric Circulation     

K. Pandžić  D. Trninić 《Theoretical and Applied Climatology》1998,61(1-2):69-76

Summary The Sava river annual precipitation field and the discharge anomalies in the Sava river catchment are compared to each other and to mean sea-level pressure anomalies over Europe. In addition to a correlation analysis a clustering technique is used for the time series from 1901–1990. Discharge data are available only for the period 1931–1990. As expected, a high correlation exists between the Sava river discharge and precipitation, but also, remarkable correlation is found between air pressure anomalies and Sava river precipitation. Grouping the years into four classes, the correlation is shown to be especially high for extreme events. A possible application of these results might be for the downscaling of long-lead climate anomaly forecasts. Received November 30, 1995 Revised May 21, 1998  相似文献   

Rural diversification and socio-economic transformation in Croatia     

Dražen Njegać  Aleksandar Toskić 《GeoJournal》1998,46(3):263-269

Rural diversification in Croatia is well advanced because many rural families have been able to find work in secondary and tertiary activities without the need to migrate to the towns. Many rural settlements have now attained an urban character although there are regional variations, including a contrast between the continental zone with a relatively high level of commitment to agriculture and the coastal areas, with pronounced ‘deagrarisation’ where the ports and tourist resorts are well developed and the natural resource conditions for agriculture are poor. These variations are examined at the municipality level with reference to two key indicators: the share of nonagricultural population and the share of workers in the total active population. Four categories of socio-economic transformation are recognised: more urbanised, urbanised, less urbanised and rural. The main regional differences between the continental and coastal areas are confirmed with the latter showing a relatively high level of socio-economic transformation through the prominence of more highly urbanised municipalities. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Protection of karst aquifers in the Dinarides in Croatia     

B. Biondić  R. Biondić  F. Dukarić 《Environmental Geology》1998,34(4):309-319

 This paper presents karst water protection measures being introduced in the Dinarides of Croatia. The spring sites for the water supply of the town of Rijeka, for its 200 000 inhabitants and the largest harbor of the northeastern side of the Adriatic Sea, have been used as a pilot research area. The European research project was used, and protection of water was generally divided into three phases. A categorization of springs has been made, and five basic protection zones have been distinguished. The rules of behavior in protected zones have been outlined. For the first time, the term water-supply "reserve" has been introduced, referring to the parts of the mountainous region where karst groundwater is recharged. Received: 26 March 1997 · Accepted: 22 July 1997  相似文献   

Time profiles of solar irradiance dips     

B. Vršnak  V. Ruždjak  Ž. Ružić 《Solar physics》1990,125(1):13-24

ACRIM data have been analyzed to study the time profiles of simple irradiance dips caused by single active regions. Comparison of the average characteristics of the dips appearing in the minimum and maximum of the solar cycle shows that there are no significant differences. In both periods we disclosed the facular irradiance excess in the profile wings having typical duration of two to three days and an amplitude of about 20% of the dip amplitude. The profiles were asymmetric, with a stronger and longer excess in the trailing wing. We determined an average profile which was attributed to an idealized active region, and we calculated the luminosity perturbation caused by it. Excess radiation in the wings of the profile compensates about 1/3 of the deficit in the dip. In the most simple case from our sample we compared the profile based on ACRIM measurements and the proxy profile estimated using sunspot and plage areas published in Solar Geophysical Data catalogues. The comparison indicates that the facular excess was compensating instantaneously about 2/3 of the luminosity deficit caused by sunspots.  相似文献