scholarly journals Seismic activity in the focus of the Uglegorsk earthquakes, Sakhalin Island in relevance to intensive development of coal deposits

2021 ◽  
Author(s):  
Dmitry Kostylev ◽  
Natalya Boginskaya ◽  
Alexander Zakupin
Keyword(s):  
Brown Coal ◽  
Coal Mine ◽  
Seismic Activity ◽  
Large Scale ◽  
Slope Angle ◽  
Sakhalin Island ◽  
Corner Frequency ◽  
Seismic Events ◽  
Velocity Spectrum ◽  
Human Engineering

Abstract Induced seismicity is an increase in seismic activity caused by the human engineering. An example of such activity is the mineral exploration, large water reservoirs construction, exploitation of underground oil and gas storages, etc. The authors studied the seismicity in the Uglegorsky district of Sakhalin region, where the Solntsevskoye brown coal field is located, which is the most promising in the island. Its area is over 100 sq. km, and productive strata of the Verkhneduiskaya formation with a thickness of up to 600 m contains 12 coal seams, 8 of which are working. Active mining of brown coal is carried out at the Solntsevsky coal mine, and blasting operations are performed on a large scale, that, as a result, does not exclude the relation of the seismic process to technogenic seismicity. The earthquake recurrence curves for two decades beginning from 2000 to the present were constructed in the work to compare the characteristics of the seismic regime in the studied area. The difference in the slope angle of recurrence graph during the period of 2011-2020 (the period of the most active development of the Solntsevsky coal mine) from the previous decade is quite significant. The maps of spatiotemporal distribution of seismic events epicenters in the vicinity of Solntsevsky coal mine are constructed. The contraction of zones of seismic events concentration to the mining areas, first of all to the Solntsevsky coal mine, have been found. Such a combination allows us to talk about an increase in seismicity of the region during the last years and change in its character from the natural to a mixed natural and technogenic. The focal mechanisms of the largest earthquakes occurred in the Uglegorsky district have been constructed in order to prove the change in seismicity character and reasons for the earthquake occurrence in the studied area. The mechanisms of seismic events of 2020 are classified as strike-slip faults, that is not character for the most earthquakes on the territory of Sakhalin Island. The authors made an attempt to determine the regularities of the parameters of the produced blasts and earthquakes through dynamic parameters of the seismic events foci by means of studying the frequency content of earthquakes and blasts in order to determine a corner frequency from the focal velocity spectrum.

scholarly journals The first results of the seismic monitoring system of the Solntsevsky open pit coal mine area (on Sakhalin Island)

2021 ◽  
Vol 946 (1) ◽  
pp. 012002
Author(s):  
D V Kostylev ◽  
N V Boginskaya
Keyword(s):  
Real Time ◽  
Monitoring System ◽  
Coal Mine ◽  
Seismic Monitoring ◽  
Sakhalin Island ◽  
Open Pit ◽  
Seismic Events ◽  
Time Data ◽  
Active Coal ◽  
First Results

Abstract In 2021, work began as a part of the implementation of the decision of the protocol of the Sakhalin branch of the Russian Expert Council on earthquake prediction, seismic hazard and risk assessment dated October 6, 2020 on detailed monitoring in the area of active coal mining at the Solntsevsky open pit coal mine (Sakhalin Island). New points of seismic monitoring were installed directly in the area of the open pit coal mine. Integration of real-time data received from the points in real time into a unified seismic monitoring system in the Sakhalin Region was ensured. The results of registration of seismic events of various origins since the commissioning of the stations are presented. A significant increase in the accuracy of the determined epicenters and the possibilities of determining earthquakes and industrial explosions has been noted. The results of the monitoring system for studying the landslide process in the area of the open pit coal mine, as well as the probable factors that caused the landslide, are shown. The developed monitoring system allows for representative registration of seismic events with ML ≥ 0.8 in the immediate vicinity of open pit coal mine, which makes it possible to control blasting operations with increased accuracy, as well as weak and possible induced seismicity formed as a result of a constant technogenic impact on the subsoil.

scholarly journals Directional Hydraulic Fracturing (DHF) of the Roof, as an Element of Rock Burst Prevention in the Light of Underground Observations and Numerical Modelling

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 562
Author(s):  
Marek Jendryś ◽  
Andrzej Hadam ◽  
Mateusz Ćwiękała
Keyword(s):  
Rock Mass ◽  
Hydraulic Fracturing ◽  
Coal Mining ◽  
Rock Burst ◽  
Coal Mine ◽  
Seismic Activity ◽  
Black Coal ◽  
Directional Hydraulic Fracturing ◽  
Before And After ◽  
The Face

The following article analyzes the effectiveness of directional hydraulic fracturing (DHF) as a method of rock burst prevention, used in black coal mining with a longwall system. In order to define changes in seismic activity due to DHF at the “Rydułtowy” Black Coal Mine (Upper Silesia, Poland), observations were made regarding the seismic activity of the rock mass during coal mining with a longwall system using roof layers collapse. The seismic activity was recorded in the area of the longwall itself, where, on a part of the runway, the rock mass was expanded before the face of the wall by interrupting the continuity of the rock layers using DHF. The following article presents measurements in the form of the number and the shock energy in the area of the observed longwall, which took place before and after the use of DHF. The second part of the article unveils the results of numerical modeling using the discrete element method, allowing to track the formation of goafs for the variant that does not take DHF into consideration, as well as with modeled fractures tracing DHF carried out in accordance with the technology used at “Rydułtowy” coal mine.

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

2021 ◽  
pp. 8-12
Author(s):  
E. E. Razumov ◽  
◽  
S. M. Prostov ◽  
G. D. Rukavishnikov ◽  
S. N. Mulev ◽  
...  
Keyword(s):  
Seismic Activity ◽  
Average Energy ◽  
Seismic Monitoring ◽  
Acoustic Properties ◽  
Signal Frequency ◽  
Monitoring Systems ◽  
Seismic Events ◽  
Seismic Monitoring Systems ◽  
Seismic Sensors ◽  
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.

scholarly journals Efectos ergonómicos inmediatos de un apoyo isquiático en la sedestación. Herramienta preventiva para la información en salud = Immediate ergonomic effects of an ischial support in the sitting position. Preventive tool for health information

2017 ◽  
Vol 8 (2) ◽  
pp. 228
Author(s):  
Luis Ceballos-Laita ◽  
Teresa Mingo-Gómez ◽  
Sandra García-Lázaro ◽  
Sandra Jiménez-del Barrio
Keyword(s):  
Slope Angle ◽  
Cross Sectional Study ◽  
Head Position ◽  
Individual Characteristics ◽  
Sitting Position ◽  
Human Engineering ◽  
Cross Sectional ◽  
Lumbar Flexion ◽  
Upper Cervical ◽  
The Individual

Resumen: Introducción: La información sobre la correcta ergonomía se ha incrementado para disminuir la prevalencia de síntomas lumbares y/o cervicales en la población. Sin embargo, el acondicionamiento y el mobiliario de las instituciones universitarias no se adecuan a las características individuales de los sujetos, lo cual dificulta el proceso. Objetivo: analizar los cambios en la postura, al incorporar un apoyo isquiático en sujetos jóvenes. Material: Estudio transversal comparativo sobre 76 sujetos universitarios voluntarios (24 varones y 52 mujeres, edad media de 20,7; DT ± 2,64). Se registró la postura mediante fotogrametría sagital con un software 2D, en posición de sedestación y en sedestación corregida mediante la colocación de un apoyo isquiático de 5 centímetros de altura. Posteriormente se analizaron los ángulos cráneo-vertebral (CV), cervical superior (CS), cervical inferior (CI), lumbar (AL). Resultados: Se encontraron diferencias estadísticamente significativas entre la posición sedente y la sedente corregida en todos los ángulos analizados (p<0,01). Consiguiendo la disminución de la flexión lumbar y de la posición de cabeza adelantada. Conclusión: La utilización de un apoyo isquiático de 5 centímetros de altura en la posición de sedestación, disminuye la flexión lumbar y la posición de cabeza adelantada en comparación con una sedestación sin apoyo en sujetos jóvenes.Palabras clave: postura, columna, comunicación, ingeniería humana, educación para la salud.Abstract: Introduction: Information about correct ergonomics is increasing in order to avoid cervical and lumbar symptoms. However, the furniture of the colleges does not fit the individual characteristics, which make difficult the process. Objective: Analyse the posture change, when an ischial support is incorporated in young population. Methods: Cross sectional study. 76 volunteers students were included (24 men and 53 women, average age 20,7 SD ± 2,64). Posture was registered with sagittal photogrammetry and analysed by 2D software, in sitting position and corrected sitting position by 5-centimeters-isquial-support. Then, Neck Slope angle (NS), Upper Cervical angle (UP) Lower cervical angle (LC) and lumbar spine angle (LS) were analysed. Results: Statistical differences were found between the sitting position and corrected sitting position in all analysed angles (p<0,01). This means less lumbar flexion and forward head position. Conclusion: A 5-centimeter-isquial-support decrease lumbar flexion and forward head position compared to sitting position without ischial support in young adults.Keywords: posture, spine, communication, human engineering, health education.

scholarly journals VÝJIMEČNÉ ZEMĚTŘESENÍ JV. OD POZNANĚ (POLSKO) ZAZNAMENANÉ 6. 1. 2012

2012 ◽  
Vol 19 (1-2) ◽  
Author(s):  
Josef Havíř ◽  
Jana Pazdírková ◽  
Zdeňka Sýkorová
Keyword(s):  
Seismic Activity ◽  
Historical Earthquakes ◽  
Seismic Events ◽  
Local Magnitude ◽  
Sequence Of Events ◽  
The Earth ◽  
Moderate Earthquake ◽  
South Moravia

On January 6, 2012, a moderate earthquake was observed in a region SE of Poznań (local magnitude ML = 3.6 according to Institute of Physics of the Earth, IPE). In this region, there haven‘t been known any historical earthquakes so far, and no natural seismic activity has been observed up to present. Similar rare occurrences of weak and moderate earthquakes were observed in a region near Kaliningrad in 2004 (sequence of events, local magnitude of strongest event being 5.0) and in south Moravia region near Znojmo in 2000 (local magnitude ML = 2.5). These facts show that even in seismically quiet regions occurence of weak to moderate seismic events (with value of magnitude ranging from 3 to 5) could be expected.

scholarly journals Brown Coal in Victoria, Australia and Maddingley Brown Coal Open Cut Mine Batter Stability

2020 ◽  
Vol 9 (3) ◽  
pp. 109-118
Author(s):  
Lei Zhao ◽  
Greg You
Keyword(s):  
Coal Seam ◽  
Brown Coal ◽  
Large Scale ◽  
Low Cost ◽  
Three Dimensional ◽  
Open Pit ◽  
Open Pit Mining ◽  
Mining Operations ◽  
Power Generators ◽  
Three Dimensional Finite Element

Brown coal is young, shallowly deposited, and widely distributed in the world. It is a fuel commonly used to generate electricity. This paper first reviews the resources and characteristics of brown coal in Victoria, Australia, and its exploitation and contribution to the economy or power supply in Victoria. Due to the shallow depth of the brown coal seam, e.g. very favorable stripping ratio, open pit mining is the only mining method used to extract the coal at low cost for power generators. With the large-scale mining operations, cases of batter failure were not rare in the area. From the comprehensive review of past failures, overburden batter tends to fail by circular sliding, coal batter tends to fail by block sliding after the overburden is stripped due to a weak water-bearing layer underneath the coal seam and tension cracks developed at the rear of the batter, and batter failure is typically coincided with peak raining seasons. Secondly, the paper reviews the case study of Maddingley Brown Coal (MBC) Open Cut Mine batter stability, including geology, hydrogeology, and hydro-mechanically coupled numerical modelling. The modelling employs three-dimensional finite element method to simulate the MBC northern batter where cracks were observed in November 2013. The comprehensive simulation covers an overburden batter, a brown coal batter, two rainfall models, and a buttressed batter. The simulated results agree well with observed data, and it is found that the rainfall at the intensity of 21mm substantially lowered the factor of safety of the coal batter.

How is the marine atmospheric boundary layer turbulence organized in the trades ?

2021 ◽  
Author(s):  
Pierre-Etienne Brilouet ◽  
Marie Lothon ◽  
Sandrine Bony
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Vertical Velocity ◽  
Large Scale ◽  
Layer Structure ◽  
Potential Temperature ◽  
Surface Wind ◽  
Cloud Amount ◽  
Velocity Spectrum ◽  
Marine Atmospheric Boundary Layer

&lt;p&gt;Tradewind clouds can exhibit a wide diversity of mesoscale organizations, and the turbulence of marine atmospheric boundary layer (MABL) can exhibit coherent structures and mesoscale circulations. One of the objectives of the EUREC4A (Elucidating the role of cloud-circulation coupling in climate) field experiment was to better understand the tight interplay between the mesoscale organization of clouds, boundary-layer processes, and the large-scale environment.&lt;/p&gt;&lt;p&gt;During the experiment, that took place East of Barbados over the Western Tropical Atlantic Ocean in Jan-Feb 2020, the French ATR-42 research aircraft was devoted to the characterization of the cloud amount and of the subcoud layer structure. &lt;span&gt;During its 17 research flights, &lt;/span&gt;&lt;span&gt;it&lt;/span&gt; &lt;span&gt;sampled a &lt;/span&gt;&lt;span&gt;large diversity of large scale conditions and &lt;/span&gt;&lt;span&gt;cloud patterns&lt;/span&gt;&lt;span&gt;. &lt;/span&gt;Multiple sensors onboard t&lt;span&gt;he aircraft measure&lt;/span&gt;&lt;span&gt;d&lt;/span&gt; &lt;span&gt;high-frequency &lt;/span&gt;&lt;span&gt;fluctuations of potential temperature, water vapour mixing ratio and wind , allowing &lt;/span&gt;&lt;span&gt;for &lt;/span&gt;&lt;span&gt;an extensive characterization &lt;/span&gt;&lt;span&gt; of&lt;/span&gt;&lt;span&gt; the turbulence &lt;/span&gt;&lt;span&gt;within&lt;/span&gt;&lt;span&gt; the subcloud layer. &lt;/span&gt; &lt;span&gt;A &lt;/span&gt;&lt;span&gt;quality-controled and calibrated turbulence data&lt;/span&gt;&lt;span&gt;set&lt;/span&gt;&lt;span&gt; was produced &lt;/span&gt;&lt;span&gt;on the basis of these measurements&lt;/span&gt;&lt;span&gt;, which is now &lt;/span&gt;&lt;span&gt; available on the EUREC4A AERIS data portal.&lt;/span&gt;&lt;/p&gt;&lt;p&gt;&lt;span&gt;The &lt;/span&gt;&lt;span&gt;MABL &lt;/span&gt;&lt;span&gt;turbulent &lt;/span&gt;&lt;span&gt;structure i&lt;/span&gt;&lt;span&gt;s&lt;/span&gt;&lt;span&gt; studied &lt;/span&gt;&lt;span&gt;using this dataset, &lt;/span&gt;&lt;span&gt;through a spectral analysis &lt;/span&gt;&lt;span&gt;of the vertical velocity&lt;/span&gt;&lt;span&gt;. Vertical profiles of characteristic length scales reveal a non-isotropic structure with a stretching of the eddies along the mean wind. The organization strength of the turbulent field is also explored &lt;/span&gt;&lt;span&gt;by defining&lt;/span&gt;&lt;span&gt; a diagnostic based on the shape of the vertical velocity spectrum. &lt;/span&gt;&lt;span&gt;The &lt;/span&gt;&lt;span&gt;structure and the degree of organization of the &lt;/span&gt;&lt;span&gt;subcloud layer &lt;/span&gt;&lt;span&gt;are&lt;/span&gt;&lt;span&gt; characterized for &lt;/span&gt;&lt;span&gt; different type&lt;/span&gt;&lt;span&gt;s&lt;/span&gt;&lt;span&gt; of mesoscale &lt;/span&gt;&lt;span&gt;convective &lt;/span&gt;&lt;span&gt;pattern &lt;/span&gt;&lt;span&gt;and &lt;/span&gt;&lt;span&gt;as a function of&lt;/span&gt;&lt;span&gt; the large-scale environment, &lt;/span&gt;&lt;span&gt;including&lt;/span&gt; &lt;span&gt;near-&lt;/span&gt;&lt;span&gt;surface wind &lt;/span&gt;&lt;span&gt;and&lt;/span&gt; &lt;span&gt;lower-&lt;/span&gt;&lt;span&gt;tropospheric&lt;/span&gt;&lt;span&gt; stability conditions.&lt;/span&gt;&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;

scholarly journals Variations of seismic activity caused by the Chandler Wobble

2019 ◽  
Vol 127 ◽  
pp. 03007
Author(s):  
Elena Blagoveshchenskaya ◽  
Evgenia Lyskova ◽  
Konstantin Sannikov
Keyword(s):  
Seismic Activity ◽  
Statistical Parameter ◽  
Specific Rotation ◽  
Temporal Variations ◽  
Chandler Wobble ◽  
Seismic Events ◽  
Slow Rotation ◽  
Global Dynamic ◽  
The Earth ◽  
Rotation Of The Earth

The problem of the correlation of the global dynamic phenomenon “Chandler wobble” with the local dynamics in different parts of the Earth’s crust and lithosphere is wide of the solution. In this study, an attempt was made to approach the solution by analyzing the temporal variations of local seismic activity in the restricted geospace volumes (GSV) within the uniform seismoactive regions. The driver of Chandler wobble is the deep mantle – the most hard and most massive Earth’s layer, whose large inertia tensor value is able to keep up Chandler’s specific rotation of the Earth for a long time. We use the geocentric coordinate system where daily rotation is absent. In this system Chandler wobble is very slow rotation of the Earth around the current equatorial axis (the pole of which is denoted as EP14). Probably, this slow rotation can influence on the seismic events in the GSV. This influence is proposed to determine by the some statistical parameter EP14gsv that indicates the most typical position EP14 on equator when the most part of the earthquakes have occurred in the given GSV. For some geospace volumes the distribution indicates certain longitudes, where the number of seismic events is maximal or minimal.

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