Martin Banov, Venera Tsolova, Georgi Zhelezov – BASIC METHODOLOGY AND MODERN TECHNOLOGICAL SOLUTIONS FOR RECLAMATION OF DISTURBED LANDS AND SOILS

Restoration of disturbed terrains is a complex problem, determined by a number of factors: geo-climatic, mining and technical conditions, mechanical and agrochemical properties of soil and geological materials to be seized. The main objective of the article is to propose a methodology for the study of disturbed lands and soils and to present the existing methods of technical and biological recultivation of these lands.

Keywords: recultivation, disturbed lands, soils

Emil Oynakov, Irena Aleksandrova – SEISMIC CHARACTERISTICS OF THE EARTHQUAKE OF 28.10.2018, GENERATED IN THE SEISMOGENIC AREA OF VRANCA, ROMANIA

On October 28th 2018, in the Focsani depression – the seismogenic zone of Vrancea, Romania, another earthquake occurred, with a large area of influence on the territory of Bulgaria. Based on an analysis if received reports, describing the feeling and other effects, an intensive map of the seismic impact on people and the environment on the territory of the country was built.The maximum intensity (I_max) with which the earthquake was felt in our country is from the 5th grade on the Medvedev–Sponheuer–Karnik scale (MSK-64). The seismic forecast properties of the microseismic noise in the minute range (i.e., half a minute report), recorded in seismic stations, located on the territory of the Balkan Peninsula were examined. It has been applied a methodology, developed by Lyubushin, A.A. (1998, 2007, 2009), corresponding to the specificity of the studied region. All calculations are done in MATLAB. Characteristic changes of the statistical parameters of the background seismic noise were determined a few days before the earthquake, expressed by the relative reduction of the parameters singular spectrum width (Δα, α*) and increase of the Hearst index (H).The effect of synchronization of ground seismic noise in the earthquake preparation stage
was sought. On the basis of the study, characteristic changes of the statistical parameters of the background seismic noise were established several days before the Vrancea earthquake (28.10.2018) with M_w = 5.5, which represents a relative decrease of the parameters Δα, α* and an increase of the parameter H. A method is presented in the study of the dynamics of the seismic noise before the event with the use of continuous time series of the statistical
parameters Δα, α* and H. The effect of synchronization of the seismic noise in the earthquake preparation stage was discovered near the epicenter and within a distance of 250 km from it.

Keywords: earthquake, seismogenic zone, macroseismic intensity, seismic noise, prognostic

Plamena Raykova, Dimcho Solakov, Stela Simeonova – SEISMIC MOMENT, STRESS DROP AND SOURCE RADIUS FOR THE SEISMIC CLUSTER OF THE 2009 EARTHQUAKE IN VALANDOVO SEISMOGENIC ZONE

In this study are presented the spectra of P- and S-waves for earthquakes from the seismic cluster (foreshock – main earthquake – aftershock) of the May 24, 2009 earthquake with moment magnitude M_w=5.3, occurred in Valandovo seismogenic zone (situated in FYR of Macedonia close to Bulgaria-Greece border region). Earthquake parameters (seismic moment, source radius, stress drop) are estimated applying Brune model. The model has been used extensively and it has been shown that it gives a good agreement with observations from many different tectonic regions and for a large range of magnitudes. The seismic moment (M0) is a direct measure of the tectonic size (product of rupture area, average static displacementand share module). Stress drop (Δσ) is the average difference between initial and final stress
along a fault before and after an earthquake. It is an important physical parameter associated with the rupture along the fault.

Earthquake occurrence is well described with the Poisson process if earthquake sequences or clusters are excluded. Such groups (or clusters) of earthquakes are foreshocks and aftershock sequences. Foreshocks are one of the few well-documented precursors to large earthquakes. Foreshocks are those earthquakes that occur before (months, days, hours) the main event in the same area. Aftershocks occur after the main shock and their frequency decays through time with approximately reciprocal of elapsed time since the main earthquake. The database is compiled using digital data from the Bulgarian Seismological Network – NOTSSI (National Operative Telemetric System for Seismological Information). Displacement spectra are generated for P- and S- waves to estimate some source parameters, such as seismic moment, stress drop, source radius and moment magnitude. The source parameters are estimated for 11 earthquakes: for five foreshocks with magnitude М_p in interval 2.8 ÷ 4.3, for the main event with magnitude М_w=5.3 and for five aftershocks with magnitude Мp in interval 4.1 ÷ 5.0. The estimated stress drop values for the main event is within the expected range for moderate earthquakes. The stress drop values for the foreshocks are lower than stress drop value for the main event. The strongest aftershocks are characterized with higher stress drop values than stress drop value for the main event.

Keywords: spectral characteristics, stress drop, seismic moment

Georgi Zhelezov, Aleksander Todorov – PRODUCTIVITY OF THE MEADOW LANDSCAPES IN THE REGION OF KRAISTE BETWEEN RIVERS KONSKA AND BISTRITSA

The research observes two main directions. The first level is related with determination and differentiation of the landscape diversity. The second part consists estimation of the productivity of the landscape based on the plant productivity of the meadow landscape unites.

Keywords: landscape, potential, meadow

Janusz Rewucki – IMPACT OF AIR TRAFFIC ON ECONOMIC DEVELOPMENT IN STUTTGART

This paper analyses the impact of air traffic in Stuttgart, trends and business environment of the European air traffic. Globalization and integration processes are characteristic of new strategies of the greater number of industries, which directly impacts economic development in Stuttgart. From a long term and global perspective, air traffic is one of the economic branches that has a large acceleration in technological development in Stuttgart. Elements that support such development are seen primarily in development of information and telecommunication systems, and in development of modern aircraft engines that lower fuel consumption
but increase flight speed as the flight itself. Considering the social and economic interest of Stuttgart in creation of development politics of air traffic, it is necessary to pay attention development of all factors in air traffic when making strategic plans. In the past, air traffic was developed with national support. Besides the funding of procurement of or renewal of the fleet of air transporters, through direct investment into capital investments, Germany has financed
construction of airport infrastructure and control towers in Stuttgart (Černe, 1991).

Keywords: air traffic, economic development, Stuttgart, Germany

Stela Stefanova – TRANSFORMING THE ROMAN ARCHAEOLOGICAL HERITAGE INTO A TOURIST ATTRACTION (CASE STUDIES OF ARCHAEOLOGICAL COMPLEX “KALETO” IN THE CITY OF MEZDRA AND ANCIENT FORTRESS “KALETO” IN THE CITY OF MONTANA)

The archaeological sites from the Roman era are an integral part of the world cultural heritage. A large part of them are among the most famous tourist attractions in theworld. Their international popularity, their wide recognition and the considerable interest towards them, provoke actions aimed at their targeted integration for the purposes of tourism in our country as well. On the other hand, the significant number of Roman archaeological sites, preserved in the country, presents a favourable opportunity for their development and positioning on the tourist market. In this sense, the current report raises the question about
the transformation of the archaeological heritage into a tourist attraction by analyzing the necessary prerequisites, conditions and motives. The actual process of socialization is traced by examining the case studies of two Roman sites – the Archaeological Complex “Kaleto” in the city of Mezdra and the Ancient Fortress “Kaleto” in the city of Montana. An analysis is made of the activities carried out in the context of the attempts at their positioning on the tourist market and the popularization of the respective destination.

Keywords: Roman archaeological heritage, tourist attraction, Archaeological Complex “Kaleto” in the city of Mezdra, Ancient Fortress “Kaleto” in the city of Montana