Basic principles for building seismic monitoring systems in rockburst-hazardous coal seam mining

The main directions of development of seismic monitoring systems in underground mineral mining are analyzed. The expediency of passive registration of natural seismic activity is proved, which provides prediction of geodynamic phenomena by locating the centers of seismic events and determining their energy level. The methods of active seismic monitoring (seismic tomography, cross-borehole survey, recording of seismic signal from a rock-breaking tool) are technically more difficult to implement. The promising methods for processing seismic information are geolocation, neural network technology, cluster analysis, and integration with numerical stress–strain analysis of and changes in acoustic properties of rock mass. The configuration of the platform developed at VNIMI and the GITS seismic monitoring system, which includes from 6 to 12 three-component seismic sensors installed permanently in wells or on pedestals, is described. The detailed layouts of seismic sensors at recording points and in gateways in extraction panels are presented. The main technical characteristics of GITS are given: the signal frequency range is 0.1–1000 Hz, the minimum recorded signal level is 0.01 mV. The main test data of GITS in Komsomolskaya mine of Vorkutaugol are described: the average annual levels of seismic activity and energy of seismic events are found to be relatively stable; the relationship between seismic event with the maximum total energy and the alternating increment in the relative criterion is defined, and the local increase in the average energy of a single event in time from the moment the main roof caving is identified. Aimed to substantiate the regional and local prediction criteria of probability of geodynamic events caused by confining pressure, VNIMI implements integrated research in mines in different regions.

The processing results of the vibration records from the dams and coastal slopes of the Charvak and Andijan water reservoirs of Uzbekistan during the weak earthquakes

The article discusses the processing results of the vibration records from the dams and coastal slopes of the Charvak and Andijan water reservoirs of Uzbekistan during the weak earthquakes. It is shown, that the seismic monitoring systems were upgraded at the investigated objects. Analyzing seismic estimates, revealed, that the construction of the Charvak reservoir dam has a non-linear behavior, and it is manifested in the differences of the frequency range and transmission coefficient of the dam elements. According to the analysis of seismic data, obtained during the registration of weak earthquakes at the several measuring points of dams and coastal slopes of the Charvak and Andijan reservoirs, the vibration frequencies and the ratio of the vibration velocity amplitudes to the vibration velocity amplitudes of the reference station are varies greatly depending on the azimuth to the epicenter

Seismic Monitoring System of Baixo Sabor and Feiticeiro Dams

In the last decade Portugal made a significant set of investments in new hydroelectric projects. According the Portuguese Dam Safety Regulation and Supporting Technical Documents, and the seismic risk for the regions where the dams were built, several seismic monitoring systems were implemented. One of the most important projects was the Baixo Sabor hydroelectric scheme which includes two large dams, namely the Baixo Sabor and Feiticeiro dams. These dams are located at northeast of Portugal and are very close to a major geological fault that crosses the Portuguese territory. Considering the seismic risk of the dam’s construction area, a seismic monitoring system was provided. That system incorporates stations in the dam’s galleries and remote stations along the reservoirs to detect eventual induced reservoir seismicity. This system has been in continuous operation and the data of the recorded earthquakes records has been analyzed and processed. This paper presents some aspects of the Portuguese legislation, refers the main studies that were used, presents a brief description of the regional Baixo Sabor geological and tectonic settings, describes the main features of the seismic monitoring system and presents some of the main results obtained during the first period of operation of the dams. Doi: 10.28991/cej-2020-03091603 Full Text: PDF

GEODYNAMICS

The basic directions of the Action Plan to assess seismic hazard and seismic check of existing nuclear power plants, approved SNRCU and NNEGC "Energoatom", which is the basis for work on seismic monitoring systems of nuclear power plant in Ukraine are represented. The experience of expert of IGPH NAS in this field is explined. The basic principles, their aims and objectives are explined too. The spesification for the Rivne NPP is represented as an example. The situation for each of NPP is outlined for short term.