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Models of 2D horizontal semi-infinite in length thin-beds and their discontinuities, like a break or a fault, are under analysis. Magnetic anomalies caused by respective geologic structures appear to be created by an equivalent magnetic source of limited size in the frame of a disjunctive structure. Suppose the vertical and/or horizontal parameters of such source would be taken small with respect to the depth of the thin-bed structure. In that case, the result reaches just the expression of a 2D line-of-dipoles magnetic anomaly. Such patterns are often observed in real case studies of sedimentary basins cut by faults оr by breaks of different sizes due to possible earthquakes or river runways along plain terrain or in canyons. They are commonly associated with subtle linear features in high-resolution magnetic maps caused by the tectonic juxtaposition of sedimentary layers with different magnetic properties., XI National Geophysical Conference, 9th June 2023

Magnetic variations shows different records at each observatory. They depend mainly on the latitude of the observatory and the local time. This paper reports the definitive geomagnetic data obtained at Panagjurishte Observatory in 2016, prepared in the form of local geomagnetic indices and absolute time-series of daily mean values plots. The Solar cycle 24 was a slowly rising one having moderate amplitude (https:// www.swpc.noaa.gov/products/solar-cycle-progression). It had a “double-peaked” solar maximum, with the first peak reaching sunspot number of 99 in 2011 and the second peak in April 2014 with 101. Calculated indices show that 2016 had 62 days with “storm” level conditions of the geomagnetic field but only moderate levels have been reached. Only one day, 25.10.2016 picked at K-index 7. This is reasonable due to the fact that the sunspot numbers that year continue to decline. Verification of data quality is performed according to “IAGA guide for magnetic measurements and observatory practice”., Bulgarian Geophysical Journal, vol. 44, p. 75-91

Националният геоинформационен център (НГИЦ) е национална научна инфраструктура, чиято основна цел е интегрирането на първичните данни за геосредата и обвързването им в единна, динамична ИКТ базирана мрежа. НГИЦ обединява мониторингови мрежи, обсерватории, наблюдателни станции, лаборатории, изчислителни центрове и друго специализирано оборудване на участващите партньори, разпределени в три модула: Мониторинг и изучаване на Земята и околоземното пространство; Хидрометеорологичен мониторинг и Национален център по сеизмично инженерство. Инструменталните единици на първия модул включват уникални съоръжения като например сеизмични, акселерометрични, геодезични, метеорологични и океанографски станции, научно оборудване в няколко лаборатории (геотехническа, палеомагнитна, химична, биологична) и компютърни системи за иновативни пресмятания и обработка на данни. Чрез тях партньорите в консорциума осигуряват наблюдение на явленията, засягащи твърдата Земя (земетресения, свлачища и срутища, почви), въздуха (замърсяване, UV радиация, магнитни бури) и водите (речни, подземни и морски). Извършва се непрекъснат мониторинг на територията на цялата страна, който осигурява над 1 ТВ месечно сеизмологични, геофизични, геодезични, геоложки и океанографски данни, които са ценен материал за извършване на научни изследвания, свързани с вътрешния строеж на Земята и протичащите процеси в нейните недра, явленията, случващи се в околоземното пространство, климатичните промени и екологията., X National Geophysical Conference, 4th June 2021, p. 147-152

The NATIONAL GEOINFORMATION CENTER (NGIC) is a newly established scientific infrastructure for integration of data, data products, and facilities from all Earth observation research institutions in Bulgaria. NGIC will bring together scientists, research infrastructures and ICT (Information & Communication Technology) experts, to develop new concepts and tools for accurate, durable, and sustainable products and services concerning geo-hazards and geo-resources which are relevant to the environment and human welfare. Our vision is that integration of the existing research infrastructures will increase access and use of the multi¬disciplinary data from the Earth monitoring networks and laboratory experiments. NGIC mission is to build on new e-science opportunities to monitor and understand the dynamic and complex Earth System, to provide permanent access to geo information, to deliver reliable data and services and to support the effective prevention from natural and anthropogenic disasters and industrial accidents. NGIC has federated organization model, which means that the sources of data are owned by their independent entities and there is no absolute authority that may imperatively force rules. The center has adopted conceptual model of system architecture that uses both service and microservice concepts and may be altered according to the specifics of the organization environment and development goals of particular information system. The sustainable result of the work of NGIC will be a solid basis for conducting research on Earth and the processes associated with it, as well as an indispensable tool for managing the risk of natural disasters and accidents., Bulgarian Geophysical Journal, vol. 42, p. 37-45

Exposure means people, property, systems, or other elements present in hazard zones that are thereby subject to potential losses. Present research analyses the human exposure at one of the most dangerous earthquake zones in Bulgaria-Blagoevgrad region as one of the main parameters of the seismic risk. Seismic hazard is modelled using GIS and overlaid with one square kilometre grid of population distribution in order to determine the population exposure. We define a parameter called “population exposure index” (PEI) which has five classes: Minor, Low, Moderate, High and Major. As was expected, the seismic hazard levels of Blagoevgrad region are in the upper part of the classification scale. The Krupnik- Kresna area is fully covered with the highest 5th level and the remaining part falls within the interval limits of level 4. The total population in the Blagoevgrad region (NUTS II) is around 138 000 people. Results show that more than 45 000 people are exposed to the highest level of seismic hazard. More than 50 settlements (towns and villages) are classified with Major (5) PEI., Proceeding of 1st International Conference on Environmental Protection and Disaster RISKs, 2020, p. 353-360

Geomagnetic observatory data are used for investigation of internal Earth structure and processes occurring in the deep interior. In addition, long series of data allow extracting signals related to the Sun, Moon, Earth’s motion, etc. To obtain a 60-years long record of the hourly mean values of the geomagnetic field component a lot of efforts have been performed including scan of the old magnetic yearbooks, digitalization of the images and verification of data. As a result, geomagnetic database is created and made available through the institutional web-page and WDC Edinburgh providing basis for scientific research and analysis., Bulgarian Geophysical Journal, vol. 42, p. 46-61

Presently, in the era of Internet communication the preliminary time series (INTERMAGNET’s reported data) acquired in geomagnetic observatories are available in near-real time, while the final absolute time series (definitive data) are disseminated with many months delay, being subject to many checks. This paper reports the definitive geomagnetic data obtained in Panagyurishte observatory in 2014, prepared in the form of local geomagnetic indices and absolute time-series of daily mean values plots. Verification of data quality is performed according to “IAGA guide for magnetic measurements and observatory practice”., Bulgarian Geophysical Journal, vol. 42, p. 62-76

Presently, in the era of Internet communication the preliminary time series (INTERMAGNET’s reported data) acquired in geomagnetic observatories are available in near-real time, while the final absolute time series (definitive data) are disseminated with many months delay, being subject to many checks. This paper reports the definitive geomagnetic data obtained in Panagjurishte observatory in 2013, prepared in the form of local geomagnetic indices and absolute time-series of daily mean values plots. Verification of data quality is performed according to “IAGA guide for magnetic measurements and observatory practice”., Bulgarian Geophysical Journal, vol. 41, p. 65-82

Presently, in the era of Internet communication the preliminary time series (INTERMAGNET’s reported data) acquired in geomagnetic observatories are available in near-real time, while the final absolute time series (definitive data) are disseminated with many months delay, being subject to many checks. This paper reports the quasi-definitive geomagnetic data obtained in Panagyurishte observatory in 2012, prepared in the form of local geomagnetic indices and absolute time-series of hourly mean values plots. Verification of data quality is performed according to “IAGA guide for magnetic measurements and observatory practice”., Bulgarian Geophysical Journal, vol. 38, p. 51-78

ESNET project is working in the frame of the Joint Operational Programme “Black Sea Basin 2007-2013” financed by EU and national co-financing. The project objective is to contribute to the prevention of natural disasters generated by earthquakes in Black Sea basin by developing a joint monitoring and intervention concept between the partner countries (Romania, Bulgaria, Moldova and Turkey, see Fig. 1). Its duration is 24 months starting in March 2012 and has five major groups of activities. In the end of project implementation the disaster potential, with accent on the seismic risk degree and the earthquakes effects in the intervention area will be assessed, an integrated seismic monitoring and intervention concept will be developed and the capacity of local emergency intervention units for joint response activities in case of disasters will be increased. The present paper describes the expected crossborder impact of the action, its methodology and final results and outputs for the project’s beneficiaries., Bulgarian Geophysical Journal, vol. 38, p. 44-50

Although the modern electronic devices are used as a primary direction indicators for aircrafts, magnetic compasses remain important back-up systems on airplanes. Airports infrastructure must include special sites which allow an aircraft check to be performed, and to calibrate onboard compasses. There are certain requirements towards those sites and the most important one is the geomagnetic declination homogeneity. The present paper describes methodology and results of the geomagnetic survey performed at the Sofia airport investigating the suitability of the north deicing pad to be used as a calibration site for aircraft compass systems. The total intensity of the geomagnetic field and geomagnetic declination were measured and analyzed. As a result, major magnetic disturbers were delineated and the suitable for compass calibration area was determined., Bulgarian Geophysical Journal, vol. 37, p. 105-112