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A bibliography of papers, reports and books authored by Stjepan Mohorovičić is compiled and is presented in this paper. The bibliography contains 440 entries grouped into five categories: scientific papers (89 entries), professional and popular papers (87 entries), data reports (69 entries), literature reports (189 entries), and monographs and books (6 entries). A significant fraction of the papers and reports were published in international journals. The list reveals that Stjepan Mohorovičić was one of the most versatile and productive scientists working in Croatia in the twentieth century, whereas a brief overview of the impact of his publications, also presented in this paper, shows that he was one of the most creative Croatian scientists as well. It is stressed that Stjepan Mohorovičić's output merits an in-depth evaluation and the bibliography is offered as the starting point for such an endeavor. [ABSTRACT FROM AUTHOR]

This document is a compilation of various research papers and abstracts related to seismic activity and earthquake research in Croatia and Hungary. The papers cover topics such as seismic site amplification, site response analysis, local site effects, lithosphere structure, gravity anomaly models, and seismic performance assessment of buildings. The research provides valuable insights into earthquake risk and mitigation strategies in the region. The document also includes links to additional information and resources for further exploration. [Extracted from the article]

This paper examines the expected future heat load in five Croatian cities: Dubrovnik, Zadar, Rijeka, Zagreb, and Osijek. The heat load is estimated by temperature-related climate indices and mean, maximum and minimum daily temperatures obtained by climate simulations using two different regional climate models (DHMZ-RegCM4 and SMHI-RCA4) with a horizontal resolution of 12.5 km, forced with two global climate models (EC-EARTH and MPI-ESMMR/LR) for two different greenhouse gas concentration scenarios (RCP4.5 and RCP8.5). By comparing these variables for the period 2041-2070 with respect to the current climate (defined as that of the period 1991-2020), a significant increase in mean, maximum and minimum temperatures was observed in all analysed combinations of regional and global climate models for all analysed cities. Although there is a difference in results depending on the combination of regional and global models, the largest increase is mainly found in the warm part of the year (April-October), with the strongest warming of Dubrovnik and Rijeka. Due to similar trends in minimum and maximum temperatures, the trend in the daily temperature range is weak. Under warmer climate conditions, the number of days with a maximum air temperature above 25 ℃ increases in all considered cities (especially in Dubrovnik), as does the number of days with a minimum air temperature exceeding 20 ℃ (especially in Rijeka and Zadar). Furthermore, a reduction in the number of days with maximum and minimum temperatures below 0 ℃ is projected for all cities. Nevertheless, some differences are found between coastal and inland cities caused by local factors. [ABSTRACT FROM AUTHOR]

This paper presents two novel spectral soil area indices to identify bare soil area and distinguish it more accurately from the urban impervious surface area (ISA). This study designs these indices based on medium spatial resolution remote sensing data from Landsat 8 OLI dataset. Extracting bare soil or urban ISA is more challenging than extracting water bodies or vegetation in multispectral Remote Sensing (RS). Bare soil and the urban ISA area often were mixed because of their spectral similarity in multispectral sensors. This study proposes Normalized Soil Area Index 1 (NSAI1) and Normalized Soil Area Index 2 (NSAI2) using typical multispectral bands. Experiments show that these two indices have an overall accuracy of around 90%. The spectral similarity index (SDI) shows these two indices have higher separability between soil area and ISA than previous indices. The result shows that percentile thresholds can effectively classify bare soil areas from the background. The combined use of both indices measured the soil area of the study area over 71 km2. Most importantly, proposed soil indices can refine urban ISA measurement accuracy in spatiotemporal studies. [ABSTRACT FROM AUTHOR]

Soil erosion is one of the most prominent geomorphological hazards threatening environmental sustainability in the coastal region of western Syria. The current war conditions in Syria has led to a lack of field data and measurements related to assessing soil erosion. Mapping the spatial distribution of potential soil erosion is a basic step in implementing soil preservation procedures mainly in the river catchments. The present paper aims to conduct a comprehensive assessment of soil erosion severity using revised universal soil loss equation (RUSLE) and remote sensing (RS) data in geographic information system (GIS) environment across the whole Al-Qshish river basin. Quantitatively, the annual rate of soil erosion in the study basin was 81.1 t ha-1 year-1 with a spatial average reaching 55.2 t ha-1 year-1. Spatially, the soil erosion risk map was produced with classification into five susceptible-zones: very low (41 %), low (40.5%), moderate (8.9%), high (5.4%) and very high (4.2%). The current study presented a reliable assessment of soil loss rates and classification of erosionsusceptible areas within the study basin. These outputs can be relied upon to create measures for maintaining areas with high and very high soil erosion susceptibility under the current war conditions. [ABSTRACT FROM AUTHOR]

The procedures and interpretation of the magnetic data measured over the Mid-Atlantic Ocean Ridge by Swarm-A satellite is discussed in this paper. The data processing procedure has four phases after the data format conversion. The first phase is the selecting data whose Kp index is lower than 1. Secondly, the main magnetic field should be subtracted from the measured data for example through the IGRF model. This step is followed by removing trend, related to the satellite trajectory. The final step is eliminating the dipole nature of the magnetic field via Reduction to the Pole (RTP). Nonetheless, the RTP process might cause misinterpretation over the large study area and lower latitudes. Therefore, the amplitude of the analytic signal (AS) is used as an alternative to the RTP. The qualitative interpretation of the magnetic anomaly is conducted via AS anomaly, bathymetry, heat flow and tectonic map. Quantitatively correlation coefficients of bathymetry and heat flow with respect to AS are interpreted. [ABSTRACT FROM AUTHOR]

This paper is devoted to applications of the "Extremum" loss simulation system to two damaging earthquakes which occurred in Croatia in 2020. We provide a calibration procedure of mathematical models used for shaking intensity simulation. The regional macroseismic field parameters, such as the coefficients in the macroseismic field equation; the ratio between the longer (b) and the shorter (a) axes of the higher elliptical isoseismals (the flattening ratio k); the angle that specifies the orientation of the macroseismic field, in particular, the azimuth of the longer axis in the isoseismal ellipse, were all based on extensive macroseismic data acquired for the Balkan region and on the data for an analogous area with similar seismotectonic parameters in the Caucasus. We obtained a fairly good consistency between the results of simulation applied to the impact of the 2020 Croatia earthquakes and observations, confirming that the calibration of the macroseismic model by the Extremum system was both reasonable and effective for enhancing reliability for real time loss estimation. [ABSTRACT FROM AUTHOR]

Analyses of available data (newspaper reports, historical and church chronicles, chronical earthquake overviews, travel books, monographies, research papers, etc.) on effects of the earthquakes that shook the greater Ormož area at the Slovenian-Croatian border in the 1838 and 1839 revealed that one of them, recorded in a number of regional and global catalogues, is in fact a fake - the earthquake of 26 August 1838 never happened. This error creeped into various reports and studies, and then into many relevant catalogues, so this event should by systematically erased from the catalogues used to estimate seismicity rates in the neighbourhoods of north-western Croatia, north-eastern Slovenia, and south-western Hungary. Regarding the earthquake of 31 July 1838, we used important new sources of information that have not been consulted in any previous study. This made inversion of macroseismic parameters more robust. Our estimates of the macroseismic moment magnitude (Mwm = 4.8) is mostly higher than the values reported in the available catalogues. Reliable information on the effects of the smaller event of 22 March 1839 were found for two localities only, so its epicentre was placed into the town of Ormož where the maximum intensity was observed. Its estimated moment magnitude (Mwm = 4.4) is close to the median of values found in the six consulted catalogues that listed this event. The macroseismic epicentre of the 1838 earthquake lies close to the junction of surface traces of the Donat strike-slip fault and the reverse Čakovec fault. Based on their assumed geometry and the location of the macroseismic hypocentre, we give slight preference to the Donat fault as the seismogenic source. [ABSTRACT FROM AUTHOR]

A combination of different statistical methods and flow duration curves was used to examine hydraulic connection between the Plitvica stream and the surrounding piezometers that capture the groundwater of the Varaždin alluvial aquifer. Also, rainfall quantities over a wider study area were considered to examine the effect of precipitation on Plitvica water levels and groundwater levels. The following statistical methods were used in this paper: the correlation method, the auto-correlation method, and the cross-correlation method. Correlation analysis show that there is generally a significant correlation between the Plitvica water levels and groundwater levels, with positive direction of the correlation. The analysis of auto-correlograms for groundwater and surface water shows that the correlation coefficient value drops below 0.2 after a longer period, which indicates a long-term memory of the system that can be explained by the slow flow and thus slow pressure transfer. Cross-correlation analyses of the time series of the Plitvica water levels and groundwater levels showed a time lag of 1-2 days with a fairly significant cross-correlation coefficient. For precipitation and groundwater levels, the relationship is much weaker, with a lag time of 4-5 days with a weak cross-correlation coefficient. The least time lag, within a day, was established between precipitation and Plitvica water levels. Analyses of the flow duration curves revealed that Plitvica almost completely drains groundwater, except in the vicinity of the piezometer 2178 where Plitvica recharges the aquifer about a quarter of the time. [ABSTRACT FROM AUTHOR]

Renewable energy is one of the most important factors for developed and sustainable societies. However, its utilization in electrical power grid systems can be very challenging regarding rates predictably. Renewable energy depends mainly on environmental conditions such as rainfall-runoff ratios and temperature. Because of that, the expected power production heavily fluctuates, which makes the prediction and calculation of feed-in into the power grid very challenging. The accurate forecasting of energy production is a very crucial issue for power management process. This paper presents the results of deploying Machine Learning Techniques in short-term forecasting of the amount of energy produced of General Circulation Models (GCMs) Data by Almus Dam and Hydroelectric Power Plant in Tokat, Turkey. The study demonstrates the use of modeling techniques in hydropower forecasting process using the predicted monthly hydroelectric power generation data of GCMs from 2018 to 2080. Decision Tree, Deep Learning, Generalized Linear, Gradient Boosted Trees and Random Forest models are utilized to forecast the hydropower production. The results show that the correlation value of the gradient boosted trees model equals 0.717, which means that the gradient boosted trees model is the most successful model for the present data. The gradient boosted trees model used in the prediction process for each GCM in each scenario is 4.5 and 8.5. The results show that there are small differences between the models, which means that the predictions are going in similar directions for all these models. [ABSTRACT FROM AUTHOR]

Satellite gravity data are widely used in the field of geophysics to study deep structures at the regional and global scales. These data comprise free-air gravity anomaly data, which usually need to be corrected to a Bouguer gravity anomaly for practical application. Bouguer reduction approaches can be divided into two methods based on the coordinate system: the spherical coordinates method (SBG) and the Cartesian coordinates method; the latter is further divided into the CEBG and CBG methods, which do and do not include the Earth's curvature correction. In this paper, free-air gravity anomaly data from the eastern Tibetan Plateau and its adjacent areas were used as the basic data to compare the CBG, CEBG, and SBG Bouguer gravity correction methods. The comparison of these three Bouguer gravity correction methods shows that the effect of the Earth's curvature on the gravitational effect increases with increasing elevation in the study area. We want to understand the inversion accuracy for the data obtained by different Bouguer gravity reduction approaches. The depth distributions of the Moho were obtained by the interface inversion of the Bouguer gravity anomalies obtained by the CBG, CEBG, and SBG, and active seismic profiles were used as references for comparison and evaluation. The results show that the depths of the Moho obtained by the SBG inversion are more consistent with the measured seismic profile depths. Therefore, the SBG method is recommended as the most realistic approach in the process of global or regional research employing gravity data. [ABSTRACT FROM AUTHOR]

This paper presents a nature-based algorithm, titled multivariable teaching-learning-based optimization (MTLBO) algorithm. MTLBO algorithm during an iterative process can estimates the best values of the buried structure (model) parameters in a multi-objective problem. The algorithm works in two computa-tional phases: the teacher phase and the learner phase. The major purpose of the MTLBO algorithm is to modify the value of the learners and thus, improving the value of the model parameters which leads to the optimal solution. The variables of each learner (model) are the depth (z), amplitude coefficient (k), shape factor (q), angle of effective magnetization (Î,) and axis location (x0) parameters. We employ MTLBO method for the magnetic anomalies caused by the buried structures with a simple geometric shape such as sphere and horizontal cylinder. The efficiency of the MTLBO is also studied by noise corruption synthetic data, as the acceptable results were obtained. We have applied the MTLBO for the interpretation of the four magnetic anomaly profiles from Iran, Brazil and India. [ABSTRACT FROM AUTHOR]

Global flood hazard is gradually increasing. Though it is impossible to avoid them, losses and damage of hazards (e.g., floods, cyclones, and earthquakes) could be efficiently reduced by reducing household vulnerability with appropriate measures. This study aims to quantitatively measure the household vulnerability of flood hazards as a mitigation tool. It also proposed a unique approach to quantify flood-hazard household vulnerability, and shows its application in the flood prone city of Dhaka as an example case. Data were collected from both slum and non-slum areas to cover the entire urban habitat, and to compare their level of flood vulnerability. A total of 300 households were surveyed by structured questionnaire on the basis of five factors (economic, social, environmental, structural, and institutional) of flood vulnerability. The analytical hierarchy process (AHP) was applied to measure individual household vulnerability scores by using the relative weightage of variables and indicators with proper standardisation. Analytical results demonstrated that 63.06% slum and 20.02% non-slum households were highly vulnerable to floods. In addition, this paper determined and assessed responsible factors for household flood vulnerability in Dhaka. For structural vulnerability, results exhibited that 82% of slum households were highly vulnerable, and 95.3% of non-slum households were moderately vulnerable. Socially, 67.3% of slum and 78.7% of non-slum households were moderately and low-vulnerable. The majority of slum and non-slum households (84% and 59.3%, respectively) showed high and moderate vulnerability with respect to economic vulnerability. Moreover, 69.3% of slum and 65.3% of nonslum household institutional vulnerability levels were high. Of slum inhabitants, 63.3% were environmentally at high risk, and 78% of non-slum habitats were in the low-vulnerability category. However, as an effective tool to measure location-specific vulnerability, it is applicable for the measuring vulnerability of other cities in the world with proper customisation. On the basis of this study, future research could be conducted with more factors, variables, and indicators of human vulnerability to natural or artificial hazards/disasters. Future work may provide a better reflection of the vulnerability status of single/multiple hazard(s)/disaster(s). [ABSTRACT FROM AUTHOR]

In orientation and navigation using compass, reliable map's marginal information of Earth's magnetic field declination and its annual variation, namely geomagnetic information (GI), is crucial. Monitoring geomagnetic information means observing declination and its annual variation and checking the reliability of the actual GI model. A typical way of monitoring GI across a national territory involves conducting periodic geomagnetic network surveys to assess and update the model. The objective of the paper was to investigate improving the GI model reliability when an earlier model's error was raised to standard accuracy, and repeat station network surveys were not yet completed. A series of processing steps in modelling were revised to preserve the original data reliability. The partial 2008.5, 2009.5 and 2010.5 declination solutions were directly reduced to epoch 2015.0, and then to 2016.0, using the IGRF-12 model. The next step was to use 2016 and 2017 quiet daily declination means to estimate corresponding annual variations at surrounding observatories and repeat stations. Normal declination annual variation models were then built for further reductions to epoch 2017.0, and 2018.0, and for forward extrapolations. The quiet days observatory data were analysed to estimate the effect of the input time series length and linear extrapolated time span on forward extrapolation error. Thus, the reliability decline of the initial GI model slowed down in the sequence of models presented. The final GI2018v2 model, valid for 2018.0-2019.0, proved reliable in comparison to the repeat station declination observations of 2018. [ABSTRACT FROM AUTHOR]

This paper presents the empirically based ground truth criteria, or shorter GT criteria, for the estimation of the epicentral location accuracy of the seismic events recorded at network stations within 400 km around the city of Zagreb. The criteria are based only on the network coverage metrics and the GT5 level represents an absolute location error lower than 5 km. They have been developed using a bootstrap resampling method: same earthquakes have been relocated many times but with different, randomly selected seismic stations. We used 330 reference events taken from the pages of ISC (ISC Reference Event Bulletin, 2008) and showed that the location accuracy is most affected by the distance to the farthest station in the seismic network, while not at all influenced by the distance to the nearest. The developed GT criteria for GT595% level of accuracy require 10 or more network stations, all within 125 km from the epicentre, and the secondary azimuthal gap (the largest gap when any given station is removed from the network) less than 200°, or the network quality metric (the deviation between the optimal uniformly distributed network and the actual network) less than 0.41. The obtained results revealed that the global criteria are too restrictive and unsuitable for the studied area since they require more regular networks. With our criteria, it is possible to achieve higher accuracy for the networks with a bigger secondary azimuthal gap or greater network quality metric. In addition, our criteria limitations are shown for the areas with simpler geological structure. [ABSTRACT FROM AUTHOR]

This paper is dedicated to modeling extreme TEC (Total Electron Content) values at the territory of Serbia. For the extreme TEC values, we consider the maximum values from the peak of the 11-year cycle of solar activity in the years 2013, 2014 and 2015 for the days of the winter and summer solstice and autumnal and vernal equinox. The average TEC values between 10 and 12 UT (Universal Time) were treated. As the basic data for all processing, we used GNSS (Global Navigation Satellite System) observation obtained by three permanent stations located in the territory of Serbia. Those data, we accept as actual, i.e. as a "true TEC values". The main objectives of this research were to examine the possibility to use two machine learning techniques: neural networks and support vector machine. In order to emphasize the quality of applied techniques, all results are adequately compared to the TEC values obtained by using International Reference Ionosphere global model. In addition, we separately analyzed the quality of techniques throughout temporal and spatial-temporal approach. [ABSTRACT FROM AUTHOR]

The use of unsaturated hydraulic conductivity can help to define soil permeability, i.e. can contribute to the estimation of water percolation through unsaturated zone. The goal of this paper was the estimation of soil permeability at the location of case study profile Kosnica, situated in the alluvial plain of the Zagreb aquifer, Croatia, based on the variation in soil water content. Zagreb aquifer represents the only source of potable water for inhabitants of the City of Zagreb and Zagreb County. The thickness of unsaturated zone of the Zagreb aquifer varies from 8 meters in NW part to 2 meters in SE part. The unsaturated hydraulic conductivity values were calculated according to the granulometric composition of soil horizons and with optimized soil parameters. Variation in unsaturated hydraulic conductivity showed that the upper part of the soil profile was generally permeable throughout the 2011/2012 hydrologic year. The unsaturated hydraulic conductivity calculated with optimized soil parameters gave the highest values, always greater than 1E-9 m/s. Even though the estimation of soil profile permeability would be more precise with measurements of water content and pressure head in each soil horizon, calculation performed in this manner can give the first insight in general estimation of the unsaturated hydraulic conductivity variability and related soil permeability. [ABSTRACT FROM AUTHOR]

The paper presents the empirical use of height movement kinematic model of Earth's crust created for territory of the Croatia, Slovenia and Bosnia and Herzegovina, in order to determine the relative height displacements of crust discrete points between different epochs. Also, presents the use of this model for the purpose of direct levelling measurement reductions determination, from surveying epoch to another unambiguously selected epoch, i.e. in purpose of height movement effects elimination from levelling network node benchmarks. For Croatian territory the quality of the kinematic model is indirectly tested, founded on the comparison of levelling measurement accuracy criteria related to the state II order levelling networks constituted with original and reduced levelling measurements. Levelling lines of two levelling networks of the II order, on the area of two deliberately selected and representative levelling loops of the Croatian state levelling network of I order, were analyzed. An accuracy criterion, using the original measurements and comparatively using the reduced measurements from their survey epoch to the I order network surveying epoch, is determined. Comparative comparison of the original and reduced measurement accuracy criteria is not clearly and unequivocally confirmed, nor completely rejected, the adequacy of the kinematic model quality for measurement reductions determination. However, comparison points to the fact that the quality of the kinematic model enables reliable determination of the relative height displacements at the centimeter level. [ABSTRACT FROM AUTHOR]

Persistence and evolution of trends of mean and high river flows from six hydrological stations on watercourses of the Kupa River (Kupari, Kamanje), tributary Čabranka (Zamost 2), Dobra River (Stative donje, Trošmarija), Mrežnica River (Mrzlo polje) and annual precipitation on three meteorological stations (Parg, Ogulin and Karlovac) were analysed. The paper focuses on seven indicators: annual mean flow, seasonal mean flows (winter and summer mean flows), instantaneous annual maximum flow, annual and seasonal precipitation. Analysed time series range from 1951 to 2013, and the fixed period ranges from 1984 to 2013. Time series of each indicator was scaled to standardized flow anomaly and was analysed using the Mann-Kendall Z test for monotonic trend, after which it is smoothed using LOESS algorithm. The analysis was conducted for each indicator for full record, e.g. 1951-2013, then 1952-2013 and so on until 1984-2013. Thus, the sample size varies from 63 to 30 years. The smoothed standardized flow anomaly is easily comparable among different hydrologic stations. The standardized flow anomaly on all analysed stations for all analysed indicators shows lower mean value than long-time average after mid-1980's, when fixed period starts. Further analysis of summer and winter seasonal mean flows revealed different deviation from long-term annual flow average. Trend evolution of certain indicators was proven using Mann-Kendall Z test, by plotting Z values for each iteration of start year (1951 to 1984). [ABSTRACT FROM AUTHOR]

Persistence and evolution of trends of mean and high river flows from six hydrological stations on watercourses of the Kupa River (Kupari, Kamanje), tributary Čabranka (Zamost 2), Dobra River (Stative donje, Trošmarija), Mrežnica River (Mrzlo polje) and annual precipitation on three meteorological stations (Parg, Ogulin and Karlovac) were analysed. The paper focuses on seven indicators: annual mean flow, seasonal mean flows (winter and summer mean flows), instantaneous annual maximum flow, annual and seasonal precipitation. Analysed time series range from 1951 to 2013, and the fixed period ranges from 1984 to 2013. Time series of each indicator was scaled to standardized flow anomaly and was analysed using the Mann-Kendall Z test for monotonic trend, after which it is smoothed using LOESS algorithm. The analysis was conducted for each indicator for full record, e.g. 1951-2013, then 1952-2013 and so on until 1984-2013. Thus, the sample size varies from 63 to 30 years. The smoothed standardized flow anomaly is easily comparable among different hydrologic stations. The standardized flow anomaly on all analysed stations for all analysed indicators shows lower mean value than long-time average after mid-1980's, when fixed period starts. Further analysis of summer and winter seasonal mean flows revealed different deviation from long-term annual flow average. Trend evolution of certain indicators was proven using Mann-Kendall Z test, by plotting Z values for each iteration of start year (1951 to 1984). [ABSTRACT FROM AUTHOR]

The use of unsaturated hydraulic conductivity can help to define soil permeability, i.e. can contribute to the estimation of water percolation through unsaturated zone. The goal of this paper was the estimation of soil permeability at the location of case study profile Kosnica, situated in the alluvial plain of the Zagreb aquifer, Croatia, based on the variation in soil water content. Zagreb aquifer represents the only source of potable water for inhabitants of the City of Zagreb and Zagreb County. The thickness of unsaturated zone of the Zagreb aquifer varies from 8 meters in NW part to 2 meters in SE part. The unsaturated hydraulic conductivity values were calculated according to the granulometric composition of soil horizons and with optimized soil parameters. Variation in unsaturated hydraulic conductivity showed that the upper part of the soil profile was generally permeable throughout the 2011/2012 hydrologic year. The unsaturated hydraulic conductivity calculated with optimized soil parameters gave the highest values, always greater than 1E-9 m/s. Even though the estimation of soil profile permeability would be more precise with measurements of water content and pressure head in each soil horizon, calculation performed in this manner can give the first insight in general estimation of the unsaturated hydraulic conductivity variability and related soil permeability. [ABSTRACT FROM AUTHOR]

The paper presents the empirical use of height movement kinematic model of Earth's crust created for territory of the Croatia, Slovenia and Bosnia and Herzegovina, in order to determine the relative height displacements of crust discrete points between different epochs. Also, presents the use of this model for the purpose of direct levelling measurement reductions determination, from surveying epoch to another unambiguously selected epoch, i.e. in purpose of height movement effects elimination from levelling network node benchmarks. For Croatian territory the quality of the kinematic model is indirectly tested, founded on the comparison of levelling measurement accuracy criteria related to the state II order levelling networks constituted with original and reduced levelling measurements. Levelling lines of two levelling networks of the II order, on the area of two deliberately selected and representative levelling loops of the Croatian state levelling network of I order, were analyzed. An accuracy criterion, using the original measurements and comparatively using the reduced measurements from their survey epoch to the I order network surveying epoch, is determined. Comparative comparison of the original and reduced measurement accuracy criteria is not clearly and unequivocally confirmed, nor completely rejected, the adequacy of the kinematic model quality for measurement reductions determination. However, comparison points to the fact that the quality of the kinematic model enables reliable determination of the relative height displacements at the centimeter level. [ABSTRACT FROM AUTHOR]

The first part of this paper is an overview of various methodologies for seismic-geotechnical hazard zonation that conform to the recommendations of International Society for Soil Mechanics and Geotechnical Engineering (ISSMGE, 1999). The purpose of this review is to illustrate the variety of methodologies currently in use for preparation of seismic hazard maps and to evaluate basic principles of zonation for different purposes and at different scales. In the second part of the paper, input data for seismic microzonation are discussed. Promulgated seismic regulations are a prerequisite for delineation of seismic hazard zones. Guidelines and recommendations for seismic microzonation should be incorporated into seismic regulations. There are two principal approaches to earthquake loss mitigation; one relates to land use management, and the other deals with the design and construction of individual buildings. Both approaches must be considered as components of urban planning and building design, and the application and use of these approaches should be required and enforced by municipal authorities. [ABSTRACT FROM AUTHOR]

This paper describes how a geotechnical database may be generated from the information system (IS) of a geotechnical consulting company established in compliance with the ISO 9001, ISO 17025 QMS standards and Eurocode 7. The application of these principles is illustrated using a geotechnical consulting company Geokon of Zagreb, Croatia as an example. An overview of Geokon's geotechnical data management system is presented by describing the procedures for data input, maintenance, use, expansion and upgrade. Included in this paper are relevant flow charts and a hierarchy of both geotechnical databases and other databases. [ABSTRACT FROM AUTHOR]

This paper concerns the structural identification of historical masonry buildings with reference to a case study, which is discussed in detail. The building is located in Southern Italy (Lecce). It has an ancient vaulted roof that is complex and commonly found in old masonry structures. This study takes advantage of extensive historical and structural investigations of the building. Preliminary activities have been conducted to obtain information about the current state of the structure including the geometry, morphology, structural details, material properties, prior interventions, and existing damage. This process was supported by an historical investigation into the conceptual background and construction methods used to build the structure. After the historical investigation, a series of experiments, including dynamic tests, were conducted on a number of the vaults to determine their dynamic response characteristics under operational conditions. A numerical model was also determined. In this paper, the primary dynamic test results and modeling assumptions are reported. Comparisons between numerical and experimental results are discussed. [ABSTRACT FROM AUTHOR]

On the occasion of 300th anniversary of the birth of Josip Ruđer Bošković, a Jesuit, versatile scientist, philosopher, diplomat and poet - originally from Dubrovnik, who worked in the 18th century - this paper presents a contribution of his importance. This is a review of one of his first papers which has recently been translated from Latin into Croatian and which explains the appearance of northern lights. Bošković was the first Croatian scientist who dealt with the explanation of this atmospheric phenomenon, and some of his conclusions are close to modern ideas. This paper also presents a recently discovered memorial poem which his younger fellow brother p. Petar Perica wrote on the occasion of the 200th anniversary of Bošković's birth and which was hitherto unknown. [ABSTRACT FROM AUTHOR]

There is an operational requirement to formulate an objective procedure to handle operational cyclone forecasting work in a more efficient and effective way. In this paper we propose a four-step statistical-dynamical scheme for the real time application in cyclone forecasting work. The four-step scheme consists of (a) Analysis of Genesis Potential Parameter (GPP), (b) Estimation of Maximum Potential Intensity (MPI), (c) 72 hours Intensity Prediction and (d) Prediction of decaying intensity after the landfall. In November 2007, a very severe cyclonic storm 'SIDR' formed over the Bay of Bengal and hit the Bangladesh coast. In this paper, a four-step procedure is demonstrated for real time forecasting this cyclone. The results show that the GPP analysis at early stages of development can strongly indicate that the cyclone »SIDR« had enough potential to reach its cyclone stage. The MPI of the cyclone based on the SST (Sea Surface Temperature) values along the cyclone track is estimated to be 146 knots. The observed maximum intensity of the cyclone is found to be 79 % of its MPI. The 72 hours intensity prediction based on 00 UTC on 12 November could reproduce the intensity value of 109 knots, an underestimation of 6 knots. The subsequent updated forecasts are found to be realistic and useful. The 6-hourly decaying intensity forecast after the landfall shows an underestimation of 10 knots at 12 hours forecast and a significant improvement is noticed with the incorporation of correction factor. The study has documented the potentiality of the procedure for operational application. [ABSTRACT FROM AUTHOR]

This paper is primarily devoted to general discussion of HRID (High resolution isentropic diagnosis) model developed by Glasnović (1983) and its vertical time cross-sections used operationally on direct output of forecasting model ALADIN (Aire Limitee Adaptation Dynamique et Development International). HRID is based on polynomial hydrostatic adjustment technique making use of reciprocal value of thermal stability parameter and its higher order derivatives. Since these relations are applied in local points of vertical interpolation, the problem is considered analytically, eliminating the finite difference approximation procedure in layers with different isentropic thicknesses. This paper presents a local 72 hourly ALADIN/HRID forecast for the city of Split, Croatia, at the eastern Adriatic coast, with detailed vertical atmospheric structure indicating the characteristic features of a frontal passage on 2 January 2007. [ABSTRACT FROM AUTHOR]

Atmospheric drought in lowlands in Slovakia is analyzed on the bases of Standardised Precipitation Index (SPI) and Standardised Precipitation Evapotranspiration Index (SPEI). This paper gives information about the dynamic, intensity, seasonal and territorial differences in occurrence of drought with various intensity: mild (near to normal), moderate, severe and extreme for the period 1961-2011. Future changes in occurrence of drought are determined on the basis of model data (regional circulation models KNMI and MPI) for temperature and precipitation for two periods: 2001-2050 and 2051-2100. The results show that temperature has an important role for occurrence of moderate and severe drought at monthly level and precipitation is the main factor for occurrence of extreme drought. There are an increasing number of cases with severe or extreme drought in summer for most of the investigated stations. Future projection of drought shows general tendency to increasing frequency of severe dry events in 2001-2050 and 2051-2100 while there will be a little decreasing of extremely dry months in comparison to 1961-2010. [ABSTRACT FROM AUTHOR]

Height (altitude) determination in geodesy is faced with problems that are directly attributed to the method of measurements and used geoid solutions. Due to the reliability of CROPOS as well as growing progress in geoid determination (increase of their external and internal accuracy), GNSS observations using CROPOS_VRS_HTRS96 VPPS service became most commonly used method of height determination in Croatian every day geodetic practice. This paper describes establishment of 33 GNSS/levelling points using CROPOS_VRS_HTRS96 VPPS service and geometric levelling at the area of the City of Zagreb. It also gives the analysis of the quality of performed GNSS observations, analysis and comparison of the geoid undulations from official geoid solutions of the Republic of Croatia, HRG2000 and HRG2009 with undulations obtained by GNSS/levelling for established GNSS/levelling points and brief overview of current state of vertical network of the City of Zagreb. [ABSTRACT FROM AUTHOR]

This paper presents fast and effective filtering techniques for image enhancement from remote sensing Indian remote sensing satellite P6 Liss IV remotely sensed data like Near-Infrared band. There are four filtering techniques used for image enhancement based on spatial domain filters and frequency domain filters such as median filter, wiener filter, bilateral filter and Gaussian homomorphic filter and selected noises salt and pepper and Gaussian noise used with filter. Selected images tested with each filter and based on PSNR performance metric value and best filtering technique identified from these filters. Finally, Gaussian homomorphic filtering technique is suitable for image enhancement of the Liss IV remotely sensed Near-Infrared band. Image enhancement technique is preprocessing for future work such as edge detection and image segmentation. [ABSTRACT FROM AUTHOR]

This paper presents the effects of geometry of sediment bedrock interface (GSBI) of 3D basins with a circular outcropping free surface on the characteristics and the focusing of the basin-generated surface (BGS) waves and associated spatial variations of the average spectral amplification (ASA) and average aggravation factor (AAF). An increase of ASA towards the centre of the semispherical (SS-) basin as compared to the 2D basin revealed the focusing of the BGS-waves in the SS-basin. The obtained 2.8 times larger ASA at the centre of the SS-basin to that of 2D basin calls for a special attention in predicting the seismic hazard in such basins for earthquake engineering purposes. The analysis of the simulated results revealed that the amplitude amplification due to the focusing of the BGS-waves was highly affected by the GSBI. For example, the ASA at the centre of a trapezoidal basin with edge slope 20° was 50% larger than that at the centre of a trapezoidal basin with edge slope 45°. It is recommended to compute the AAF using the same components of ground motion as that of the incident wave to conservatively aggravate the ground motion to incorporate the 3D basin-effects in the seismic microzonation where it is over based on the 1D response of sediment column. [ABSTRACT FROM AUTHOR]

This paper reports the estimated response of hourly mean concentrations of selected air pollutants, namely carbon monoxide (CO), sulphur dioxide (SO2), nitrogen dioxide (NO2) and particulate matter with an aerodynamic diameter of up to 10 μm (PM10), to local scale meteorology in Zagreb, Croatia for the period 2006-2012. A new method is applied here for the urban area of Zagreb. In a general model, a logarithm of hourly mean air pollutant concentrations is expressed as the sum of the nonlinear functions of meteorological and several time variables, with the latter included accounting for temporal variation in emissions. The model can be formulated within the framework of generalized additive models (GAMs) and is additive on the logarithmic scale, which results in multiplicative effects on the original scale. Although the model is nonlinear, it is simple and easy to interpret. It quantifies the impact of meteorological conditions and emissions on air pollution. A measure of the relative importance of each predictor, partial effects and statistical evaluation of the model are also presented. Overall, the results show that the most important predictors are those related to emissions. The aggregate impact of meteorological variables in the model explained 45% of variance in CO, 14% in SO2, 25% in NO2 and 24% in PM10. This indicates that meteorology, at least on a local scale, is a noticeable driver of air quality in Zagreb. Stable atmospheric conditions in the urban area favour the occurrence of higher concentrations of air pollutants. Convection processes dominate under unstable conditions, resulting in the dilution of pollutant concentrations within the boundary layer. [ABSTRACT FROM AUTHOR]

This paper analyses current precipitation rates (PRs) and trends over the Mediterranean Sea region and their response to global climate change scenarios. The analysis uses 0.25° gridded PRs dataset over a 13-year period (1998-2010) based on remote sensing data from the Tropical Rainfall Measuring Mission. Future scenarios use the results of six global climate models (GCMs) under four representative concentration pathway scenarios (i.e., RCP26, RCP45, RCP60, and RCP85). Results indicate that the Mediterranean Sea region displays a seasonally significant (insignificant) wetter trend during cold (hot) seasons, and exhibits annual spatial variation ranging from under 15 to over 100 mm month -1 over the period 1998-2010. Sea level pressure has two different effects on precipitation over the northern (inversely related to precipitation) versus southern (directly related to precipitation) Mediterranean Sea. However, sea surface temperature is anti-correlated with precipitation. The GCMs that describe the current Mediterranean Sea precipitation most realistically are GFDL-CM3-1, MIROC-ESM-CHEM, and HadGEM2-AO, which are used to calculate the ensemble mean for each representative concentration pathway scenario. The ensemble means realizations indicate that the study area will experience substantial drought in the 21st century. Uncertainty in the projected precipitation over the Mediterranean Sea was partitioned into four sources, of which the used scenario dominates. [ABSTRACT FROM AUTHOR]

In this paper we explore the impact of vegetation cover and soil moisture coupling on climate simulations over the Europe. For this purpose, the International Centre for Theoretical Physics (ICTP) atmospheric general circulation model (AGCM) is used. The analysis is based on three targeted simulations for the period 1981-2010: a control experiment (with a simple land-surface model that mimics interaction of soil and atmosphere); an experiment with land-surface temperature and soil moisture coupling, and an experiment with both soil moisture and interactive vegetation coupling. The amplitude and interannual variability of surface air temperature, precipitation and evaporation for summer and winter seasons are examined. Compared to the control experiment, increasing of surface temperature over the continental Europe is found for the experiment with soil-moisture model for both, winter and summer seasons. However, when ICTP AGCM is coupled with the dynamic vegetation model, increasing of surface temperature is simulated only during the summer, while it is reduced during the winter. Generally, the dynamic vegetation model reduces total precipitation over the observed domain, and areas with the most pronounced decrease of the total precipitation coincide with areas of reduced evaporation. The results indicate substantial impact of soil moisture and vegetation coupling on amplitudes of simulated surface air temperature, precipitation and evaporation with predominant contribution of the soil moisture coupling. Contrary, the impact on the interannual variability of analyzed variables is rather weak. [ABSTRACT FROM AUTHOR]

An analysis of Bošković's early paper concerned with the polar light (aurora borealis) gives an insight into the validity of the mathematical method which the young Bošković applied to significant geophysical phenomena in order to comprehend their nature. Based on the given data, we have examined numerical results about the height of atmosphere and the heights of the auroras which were observed over Europe in 1726 and in 1737. In his text there is not a single mathematical formula. Following his instructions we have derived a formula which may be used to determine the distance of an aurora by observing it from one station. For the assumed aurora model, his method is applicable. We find that described ideas on the physical cause of aurora, conceived in a fluid coming from the sun, have elements of modern knowledge. [ABSTRACT FROM AUTHOR]

The rapid development of the radio communications system, especially in developed countries, has drawn the attention of telecommunication systems engineers to explore the frequency band above the Ku band. Because radio communication systems operating in the frequency band above the Ku band (10 GHz) suffer from rain attenuation during rainy conditions, prediction of rain attenuation using a 1-min rainfall rate distribution is indeed vital. However, a 1-min rainfall rate distribution is not widely available compared to rainfall rate distributions with longer integration times. Therefore, a suitable conversion method is required to predict 1-min rainfall rate distributions of distinct integration times. This paper presents several conversion methods such as Segal, Burgueno et al., Chebil and Rahman, Joo et al., EXCELL RSC and LG. The Segal method provides an overall Root Mean Square (RMS) error below 5% at different integration times and is suitable to be used in malaysia. [ABSTRACT FROM AUTHOR]

A precision/round-off error has been discovered in the tidal analysis routines used in the paper "North Adriatic tides: observations, variational data assimilation modeling, and linear tide dynamics" by J. W. Book, H. Perkins, and M. Wimbush (2009, Geofizika, 26, 115-143). Tidal elevation phases for 12 of the 15 stations are, on average, too low by 3.9° for the diurnal constituents and 7.9° for the semidiurnal constituents in Tabs. 4 and 5. These tables have been corrected and are republished here. The error also had an effect on the input data used for the linear variational data assimilation model, and combined with a nearest neighbor interpolation scheme produced an approximate 15 minute forward shift in time for 6 of the 43 synthesized tidal records. The error produced final model solutions that had tidal elevation phases 3.5° too high for M2, 1.6° too high for K1, and similar matching phase shifts for other semidiurnal and diurnal constituents. The errors in the input data have been corrected, the interpolation scheme has been changed to a piecewise cubic spline method, and the model runs have all been redone. The new model results suggest a minor change in optimal friction parameter, which in turn alters model Q factors and dissipation. However, the original finding that these values are not well determined by this methodology remains true. Model and observational results originally shown in Figs. 5-7 and Figs. 13-14 have slightly changed and are republished here. The main conclusions from the original work regarding Kelvin waves and TRW dynamics for the North Adriatic basin remain unaltered by these corrections. [ABSTRACT FROM AUTHOR]

In this paper a Multi-Model Ensemble (MME) technique is experimented for improving day to day rainfall forecast over India in short to medium range time scale during summer monsoon of 2010. Four operational global Numerical Weather Prediction (NWP) models namely, ECMWF, JMA, NCEP GFS and UKMO available on real time basis at India meteorological Department (IMD), New Delhi are used simultaneously with appropriate weights to obtain the MME Technique. In this technique, weights for each NWP model at each grid point is assigned on the basis of the correlation coefficient (CC) between model forecasts and observed daily rainfall time series of south west monsoon (JJAS) season. Apart from MME, a simple ensemble mean (ENSM) forecast are also generated and experimented. The rainfall prediction skill of the weighted MME is examined against ENSM and member models. The inter-comparison reveals that the weighted MME is able to provide more accurate forecast of rainfall over Indian monsoon region by taking the strength of each constituent member model. It has been further found that the rainfall prediction skill of MME is higher as compared to ENSM and member models in the short range time scale. The rainfall prediction skill of weighted MME technique improved significantly over India. [ABSTRACT FROM AUTHOR]

This paper analyses the present Egyptian Mediterranean coast (EMC) climate and the response of its climate variables to global changes. First, the accuracy of the ERA-Interim dataset (1979-2010) for the studied region is examined by comparing these data with available independent observations. Second, the qualities of six global climate models (GCMs), together with the ensemble mean of multiple model realisations of the A1B scenario, are examined by comparing these with the ERA-Interim dataset. Finally, GCM simulations are used to describe the uncertainties in future climate change along the EMC. The results indicate that the observations are in good agreement with the ERA-Interim data. The data for the EMC, 1979-2000, display a significant positive trend for 2-m air temperature together with significant negative trends for total precipitation and sea level pressure. The climate model that best describes the present EMC climate is the CGCM 3.1 model, which is used to describe the future climate of the study area. The CGCM 3.1 model indicates that the EMC area will experience significant warming, substantial droughts, and a weak decrease in sea level pressure in the end of the current century. [ABSTRACT FROM AUTHOR]

Ground-level ozone (O3) has been a serious air pollution problem for several decades and in many metropolitan areas, due to its adverse impact on the human respiratory system. Therefore, to reduce the risks of O3 related damages, developing, maintaining and improving short term ozone forecasting models is needed. This paper presents the results of two prognostic models including gene expression programming (GEP), which is a variant of genetic programming (GP), and multiple linear regression (MLR) to forecast ozone levels in real-time up to 6 hours ahead at four stations in Bilbao, Spain. The inputs to the GEP were meteorological conditions (wind speed and direction, temperature, relative humidity, pressure, solar radiation and thermal gradient), hourly ozone levels and traffic parameters (number of vehicles, occupation percentage and velocity), which were measured in the years of 1993-94. The performances of developed models were compared with observed values and were evaluated using specific performance measurements for the air quality models established in the Model Validation Kit and recommended by the US Environmental Protection Agency. It was found that the GEP in most cases gives superior predictions. Finally it can be concluded on the basis of the results of this study that gene expression programming appears to be a promising technique for the prediction of pollutant concentrations. [ABSTRACT FROM AUTHOR]

Groundwater in form of hand-dug wells and boreholes serves as the main source of drinking water to the people of south-western Nigeria. Contamination of this resource has been linked to many ambiguous pollution sources. The aim of this paper is to identify and apportion sources of pollution to groundwater in five major cities in south-western Nigeria using Principal Components Analysis (PCA). Studies on physico-chemical parameters of groundwater from Abeokuta, Ifo, Sango, Ibadan and lagos were adopted from published literatures, and evaluated using a SPSS statistical package. PCA revealed factor ranges between four and eight. Sources identified were bedrock weathering/sea water, nutrient, solids, urban/traffic runoff, industry, hardness, faecal pollution, soil leaching, nutrient, salt-water intrusion and leachate. [ABSTRACT FROM AUTHOR]

During the last years investigation of the geomagnetic field in Croatia has started and an effort to establish the geomagnetic observatory has been made. Based on the total field measured over the northern eastern part of Croatia, the suitable position for installing the geomagnetic observatory is proposed. In this paper the core field behavior from 1961 to 2002 over the entire Croatian territory was investigated by exploiting different global models. Using a regional European model the secular variation over the country was calculated. The evolution of the core field at the potential location for installing the geomagnetic observatory was analyzed in detail. The calculated field variations follow the general core field variations over Europe and there are not variations due to different induced fields or other effects at the future observatory location. This study contributes to the investigation of the potential observatory location and paves the way for better understanding of the geomagnetic field behavior over Croatia. [ABSTRACT FROM AUTHOR]

Every beginning student of geophysical fluid dynamics knows that steady--state wind-driven currents are directed to the right of the wind in the northern hemisphere. In contrast, the fact that wind-induced currents may under some specific conditions be of the opposite direction is mentioned in only a few papers. Here, a succession of simple explicit solutions is used to illustrate that the wind varying at subinertial frequencies always generates currents directed to its right, whereas at superinertial frequencies the wind rotating clockwise (counterclockwise) coincides with currents directed to its left (right). The difference is related to a dynamics differing in the two frequency bands. At subinertial frequencies, friction is primarily balanced by the Coriolis acceleration, and therefore the currents vary in phase with the wind while being directed to its right. At superinertial frequencies, the primary balance is between friction and local acceleration, implying that the currents lag behind the wind that causes them while pointing down the forcing. The former dynamic regime was originally considered by Vagn Walfrid Ekman (in 1905), the latter by Karl Jakob Zöppritz (in 1878). The destiny of the two contributions, however, was completely different: Ekman's is widely appreciated today, whereas Zöppritz's is rarely mentioned. Although Zöppritz's findings were adversely influenced by his consideration of the laminar rather than turbulent viscosity, his neglect of the Coriolis acceleration was acceptable and his solution therefore formally correct at superinertial frequencies. [ABSTRACT FROM AUTHOR]

The 2002 Molise earthquake, which was defined by seismologists as a normal event in the geodynamics of the Italian peninsula but had an international resonance due to the collapse of a primary school, triggered a series of research initiatives in earthquake engineering and significant modifications to building codes in Italy. The modifications were completed at the beginning of 2008 with the release of a new comprehensive building code for Italy. This document was mainly inspired by Eurocode, but it contains some changes and improvements. In this paper, comments are made on three specific parts of the new code: definition of seismic action, analysis of liquefaction and analysis of slope stability. For the first part, seismic action is defined based on a recent careful study of the seismic hazard in Italy. For liquefaction analysis, some developments are given, keeping the same structure used in Eurocode. Finally, for slope stability, improvements are introduced to avoid overestimation of pseudostatic forces in conventional analyses. [ABSTRACT FROM AUTHOR]

The paper presents the results of determining vertical displacements of the Earth's crust at the territory of Croatia, Slovenia, and Bosnia and Herzegovina on the basis of the data obtained in the process of establishing geometric levelling networks of the highest order of accuracy. These are the networks of the Austrian precise levelling, I. levelling of high accuracy and II. levelling of high accuracy that was established successively within the period of about 100 years (1874-1973). In accordance with the hypotheses made and the selected methodology for defining the displacements, a concrete numeric quantification of displacements has been obtained, the size and the direction of Earth's crust displacements have been determined and their characteristics and empirical parameters of behaviour indicated. It is shown that bench mark displacements are of significant amount as related to the measurement accuracy of height differences in levelling networks and that long-wave and short-wave component of their variation can be noticed in correlation with the positional distribution of bench marks. The displacements have been modelled by means of so called grid models created by the combination of the regression modelling and the minimal curvature surface modelling. Thus, on the basis of modelled vertical displacement values the speed of uniform vertical crustal movements has been determined. In spite of the fact that a very simple methodology of displacement and movement determination has been used, that is based on the absolute heights of identical bench marks positioned in various epochs - networks, the obtained results present an adequate starting point for the selection and application of more sophisticated methodologies in determining and modelling of displacements in the forthcoming research, i.e. the starting point that enables interdisciplinary explanation of geodynamic processes leading to the changes in the shape and geometry of the Earth's crust at the observed area. [ABSTRACT FROM AUTHOR]

A field load testing is an effective method for understanding the behavior and fundamental characteristics of cable-stayed bridges. This paper presents results of the behavior of the reconstructed cable-stayed bridge over river Danube in Novi Sad under test load. The bridge was built between 1976 and 1981and in 1999 was heavily damaged by two Tomahawk missiles. In 2003 process of the reconstruction began and at the end of 2005 Faculty of Civil Engineering, University of Belgrade was invited to test reconstructed bridge structure. The results of static load testing presented herein include displacements, rotations and strains of the 351 m long main span. Vibrations of the bridge were obtained by impact load produced by heavy truck passing the bridge and the time history response of vertical accelerations was recorded. The frequency content of the signals was determined using Fourier transformation and five flexural natural periods were extracted. The geological structure and engineering properties of the soil are also given. A finite element model of the bridge was made and a good agreement is achieved between the experimental and analytical results. These results have shown that the bridge is in the elastic state under the code-specified serviceability load, which indicates that the bridge has adequate load-carrying capacity and can be put safely into service. [ABSTRACT FROM AUTHOR]

One of the challenging tasks for Croatian accession to the European Union is the completion of the National Annex to Eurocode 8 (EC8) that calls for the development of national seismic hazard maps. These maps need to be developed for several return periods (probabilities of exceedance) and should consider both bedrock and soil conditions. The latter is especially challenging as it calls for site characterization at a microzonation level, i.e., site characterization based upon Vs,30, SPT blow counts, and undrained shear strength, information available only in the departments of Public Works of major cities. In this paper, the authors discuss several shortcomings associated with the EC8 ground type definitions and propose their revision. The authors also present the ongoing work for preparation of the Croatian National Annex to EC8 and explain the rationale for the improvement of EC8 ground type definitions. [ABSTRACT FROM AUTHOR]

The paper describes some recent applications of the measurements of ambient vibrations (micro seismic noise) in Croatia. They include free-field measurements, as well as those done within buildings. Data obtained in the field at the studied localities are consistent with the properties of shallow geological structures known to exist there. In Zagreb, Horizontal-to-Vertical Spectral Ratios (HVSR) indicate thick alluvial cover (over 100 m) that gradually gets thinner towards the slopes of the Mt. Medvednica. A similar situation-on a smaller scale-is also encountered in Ston, where HVSR profiles reveal several tens of meters thick sedimentary cover over the bedrock which gets exposed at the Bartolomija hill. Analyses of records from Ston and Dubrovnik suggest that soil-building resonance must be seriously considered. Measurements in the buildings were analyzed by a newly developed software package FREDA-a suite of Matlab routines. Based on tests on synthetic and real data it is concluded that spectral methods are in general more robust and less dependent on parameters of the algorithm employed, than time-domain analyses. Spectral algorithms are also better in resolving higher modes. Applications to real buildings proved that analyses of shaking induced by ambient vibrations in most cases lead to well constrained, reliable, and time independent estimates of frequencies and damping of the buildings' vibrational modes for small excitation levels. [ABSTRACT FROM AUTHOR]

The implementation of VGR-stress imaging technique, as a free surface boundary condition, in a (2, 4) staggered grid P-SV wave finite difference (FD) algorithm with a variable size of a grid cell is presented in this paper. VGR is acronym for 'vertical grid-size reduction'. The qualitative and quantitative results confirmed that the effective thickness (ETH) of the first soil layer become less by one-half of the vertical size of a grid cell than the assigned thickness (ATH), if stress imaging technique is used as a free surface boundary condition. The results of various numerical experiments revealed that the stress imaging technique causes significant numerical dispersion of Rayleigh waves and the VGR-stress imaging technique is efficient enough to avoid the same. So, superiority associated with the VGR-stress imaging technique over the well stress imaging technique is that it avoids both the significant numerical dispersion of Rayleigh waves in homogeneous medium and the soil thickness discrepancy. The maximum grid spacing ratio (ratio of largest to smallest size of a grid cell) up to 6.0 did not affect the accuracy of FD algorithm with a variable size of a grid cell. In case of a variable size of a grid cell, the required computational memory and time for a particular basin-edge model was 6.43 and 16.62 times lesser than that required in case of uniform grid. [ABSTRACT FROM AUTHOR]