Quarry Explosions Research Articles

Geoecological monitoring during mining operations

In recent decades environmental quality assessment has become a fundamentally important task in the operation of mining enterprises. This assessment becomes an integral part of the strategy for determining maximum permissible loads for mining regions and is aimed at reducing geoecological risk in them. Technological processes of mining and processing plants generate emissions of various pollutants into the atmospheric air, lead to violation of adjacent territories. Monitoring, primarily of atmospheric air and soils, is necessary to ensure the ecological balance of such territories. Lebedinsky Mining and Processing Plant is one of the most significant sources of gas and dust emissions from massive explosions in quarries during ore extraction, which form a large dust and gas cloud, creating a risk of deterioration of the life of the population in the surrounding area. The article examines the main pollutants in soils and in the atmospheric air during mass explosions, and determines the areole of their distribution from the work site. The forecast of an increase in the concentrations of detected harmful substances for the next 50 years is given. A methodology for conducting geoecological monitoring during mining operations is proposed. The research results may be useful in assessing geoecological risks and developing measures to reduce them.

Reducing dust pollution in the production of mass explosions in quarries

A method was developed to improve the efficiency of dust suppression and increasing of efficiency of energy of explosives in bulk blasting at quarries by using at the top of the borehole sealed shell filled soapstock (waste oil and fat plant) and water in the ratio 50:50. The intensification of the process of deposition of dust over the site of the explosion allows to reduce pollution the quarry site, which has a positive effect on the ecological situation in the region production and mining operations. It is established that with the passage of explosive gases through the shell with soapstock and water in the upper part of the borehole convective heat transfer from the gas shell and the loss of a fraction, the partial pressure on the borehole wall at the location of the shell. Due to the heat loss of the dust and gas cloud loses some of its energy, which leads to a decrease in the height of its ascent and, thus, prevents the removal of it beyond the open pit area.

Минимизация риска загрязнения селитебных зон пылью при открытой добыче руд

The sphere of activity of the mining and metallurgical complex of the Kursk Magnetic Anomaly included populated areas and agricultural objects. An air dusting zone with a radius of tens of kilometers was formed around openpit mining pits. During explosions in quarries, dust clouds are formed, from which fine mobile dust is dispersed. Therefore, the regions of the Kursk magnetic anomaly are characterized by the accumulation of chemical elements, including hazard classes 1–2. The dustiness factor in ecosystems complicates the living conditions of the population, which experiences the chemical effect of natural leaching of ore mining and processing products. Disturbance in the balance of the pro-oxidant-antioxidant system can cause a variety of diseases. A radical measure to prevent disease is to reduce the volume of mobile dust during ore mining in quarries. The parameters of rock destruction by explosion depend on the crushing energy intensity, above which the action of the charges goes into the ejection zone with the formation of mobile dust. Increasing the height of the ledge reduces the energy intensity of the explosion (by reducing the consumption of explosives) and the release of mobile dust. Both convective and diffusion processes occur in a dust cloud. Quarry emissions contain metals that form toxic compounds that cause soil degradation. The reaction of living matter to the effects of pollutants is predictable, which can be the basis for regulating the state of the environment. Improving the living conditions of the biota and population in the vicinity of mining sites can be achieved by adjusting the ore mining technology. To reduce the yield of mobile dust, a combined scheme of explosive ore breaking with differentiation of the process of destruction of the base of the ledge and the main mass is recommended.

Utilization of ambient noise seismic interferometry to retrieve P‐wave reflections at Soma coal basin, Western Turkey

AbstractFollowing ambient noise seismic interferometry principles, we retrieved virtual zero‐offset vertical seismic profile shot gather using continuous seismic records obtained simultaneously during an active‐source data acquisition study from Soma coal basin, Western Turkey. We treated the data to include pure ambient noise by eliminating earthquakes, surface sweeps and quarry explosions due to mining activities. We have implemented a series of data processing steps, including spectral normalization and filtering to increase the signal‐to‐noise ratio. We produced a zero‐offset virtual shot gather by cross‐correlation and cross‐coherence methods in a coal basin for the first time and we observed the P‐wave first arrivals and reflections from the deepest coal layer (km2). Our results demonstrate that the ambient noise seismic interferometry method can serve as an alternative approach for seismic imaging and monitoring in areas where the use of active seismic sources is limited due to field conditions, provided that there are sufficient and appropriate noise sources at the wellhead.

SEISMICITY of the EAST BALTIC REGION in 2016–2017

Information on seismic monitoring in the East Baltic region for 2016–2017 is presented. During this period of time, several tectonic earthquakes occurred, the epicenters of which are located in the north and northwest of Estonia and in the area of Lake Võrtsjärv. The territory of Estonia and the adjacent waters of the Baltic Sea are still the most seismically active parts of the East Baltic region. Attention is drawn to the inherited nature of seismicity, i.e. in the areas of modern earthquakes, earthquakes had already occurred before the instrumental period. Another feature of several earthquakes in the East Baltic region is their association with meteorite craters, which are most often found in the East Baltic region in Estonia and near it, in the Baltic Sea. As before, the bulk of seismic information is associated with man-made explosions in industrial quarries and in the Baltic Sea. The identification of earthquakes of small magnitude remains an urgent problem.

Discrimination Between Small Earthquakes and Quarry Blasts in Egypt Using Spectral Source Characteristics

Source parameters calculated from displacement spectra of both P and S waves are used to discriminate between earthquakes and quarry blasts in three regions of Egypt during the 2009–2015 period. We use vertical component seismograms from 440 earthquakes and 450 quarry explosions with MD 1.5 to 3.3 to calculate source parameters, including scalar moments and corner frequencies. The Mo(P,S) vs. fc(P,S) and P- to S-wave corner frequency fc(P)/fc(S) ratios are used to distinguish quarry blasts from earthquakes. A comparison of Mo(P,S) vs. fc(P,S) for both earthquakes and explosions in Egypt demonstrates that explosions had significantly lower corner frequencies than earthquakes, particularly for S-wave displacement spectra. In contrast to the Northern and Central regions, the Southern Egyptian region provides a perfect separation of corner frequencies of earthquakes and explosions for both P- and S-waves. The empirically derived average ratio of fc(P)/fc(S) for earthquakes is 1.28, 1.26 and 1.26 in the Northern, Central and Southern Egyptian regions, respectively. For explosions, average fc(P)/fc(S) ratios are 1.89, 1.86 and 2.0 in the three Egyptian regions, respectively. According to these findings, the average ratio of fc(P) to fc(S) for explosions is higher than those for earthquakes, implying that the differences in ratios enhance the ability of the fc(P) vs. fc(S) approach to discriminate between earthquakes and explosions. Based on the average fc(P)/fc(S) ratios vs. Mw in the whole of Egypt, the observed fc(P)/fc(S) discrimination threshold value for separating quarry explosions from earthquakes is 1.51–1.52.

The Coţofeni Discoveries on the Jidovu Mountain (Zlatna): Domestic or Ritual Context?

On the Jidovu mountain in Zlatna, the exploitation of an andesite extraction quarry recently destroyed a Coţofeni site. In 2014, from the area of the peak (952 m altitude), fragments of four ceramic vessels (a pitcher, an amphora, a mug and a cup) were recovered. Afterwards, in 2015, other fragments dispersed by the quarry explosions were also discovered. The presence of these materials is very important in the context of mountain archaeology. Two possible hypotheses were discussed, regarding the presence of certain large-capacity vessels (the 30 l pitcher, the 60 l amphora) on the mountaintop: the possible exploitation of andesite and a ritualistic deposit. The first hypothesis cannot be supported, since in the Coţofeni area, there are very few artefacts made of andesite. However, the much more plausible hypothesis is that of the existence of a ritualistic deposit, since similar associations of vessels also occurred in other places of worship, especially in the caves of the Apuseni Mountains. The possibility of the existence of a seasonal inhabitation is much smaller, given the conformation of the mountain. The Coţofeni site from Jidovu is part of a region in which many Coţofeni discoveries were made, in Zlatna and in the neighbouring areas, concentrated on the upper course of the Ampoi Valley. Unfortunately, the site was destroyed, in the absence of an archaeological survey, and no other data can be recovered.

NORTHERN CAUCASUS

In 2014 a seismic network consisting of 60 stations, 57 of which were equipped with digital equipment, operated in the region. 1695 earthquakes and 63 explosions in industrial quarries were recorded within the region boundaries. In the settlements of the Caucasus, 21 earthquakes were felt. The maximum intensity did not exceed Imax=4 on the MSK-64 (SIS-17) scale. Such intensity was observed from earthquakes in the territories of Ingushetia–Chechnya and Azerbaijan. The aftershock process of the strong East Black Sea earthquake on December 23, 2012 (Мw=5.8) off the coast of Abkhazia continued. In 2014 about a hundred earthquakes with KP=5.3–9.5 were recorded. In the central part of Azov sea, two earthquakes with KP=9.9 and 7.4 were recorded in January and December. The earthquakes with intermediate depths in the Tersko-Caspian trough (Tersko-Sunzhenskaya zone) with КР> 9.5 were not recorded. Two strong earthquakes with KP=12 and intermediate depths occurred in the Kurin Depression of Azerbaijan and in the Caspian Sea. A swarm of weak earthquakes with КР=5.7–8.8 was recorded on December 13–15 in the Black Sea near Tuapse. In 2014 the most part of the earthquakes were recorded in the Tersko-Caspian and Kurin troughs, in the eastern part of the Greater Caucasus. According to the level of energy released, the seismicity of the territory of the North Caucasus in 2014 was characterized in accordance with the “SOUS-09” seismicity scale as “background average” for the observation period from 1962 to 2014.

Assessment of the spectral component of seismic vibrations of protected objects during explosions in rock quarries

The article was awarded to the honored practitioner of the URSR graduate School, the laureate of the State Prize of Ukraine, professor Vynoslavskiy Vasiliy Mikolayovich, a stretch of 27 years dean of the faculty of mining of the Kiev Polytechnic Institute. 14 September 2020 year 100 years from the day of the birth of him. The article briefly describes his life path and achievements, his life position and scientific achievements. Purpose. The purpose of this article is to study the dissipation and energy distribution of explosive pulses as they pass through the rock massif and the foundation of protected objects, as well as to study the amplitude and energy of seismic oscillations of protected objects under the action of an explosive pulse. Methodology. To study the dissipation and energy distribution of explosive pulses and the interpretation of the results in this article used the methods of spectral analysis (study of autocovariance functions, joint covariance functions, energy autospectras and cross-spectral analysis).Findings. The amplitude of seismic oscillations of the output pulse (foundation surface) for the system "soil - foundation" is 7.35 times lower than the amplitude of soil oscillations at a distance of 70 m from the experimental object, the energy decreased by 8.23 times. This indicates that the foundation of the research object absorbed about 88% of the seismic energy that approached it. The frequency range 5-9 Hz is resonant. In this range, the oscillation frequency of the object foundation is close to the oscillation frequency of the input pulse, which leads to an increase in the energy and amplitude of seismic oscillations and the formation of microcracks in the foundation. For the system "foundation - the top of the tower" the amplitude and energy of oscillations at the top of the tower is 2 times greater than on the surface of the foundation. This fact indicates that due to the significant height of the towers (42.6 m), there is a rocking under the action of an explosive impulse. The maximum amplitude of oscillations of the top of the tower and the surface of the foundation is observed at a frequency of 5 Hz. This indicates that the foundation and towers respond to the explosive impulse as a single object. The nature and form of phase-amplitude characteristics of mutual spectra (hodographs) indicate that the experimental system "source of the explosion-soil massif-foundation-tower for cement storage" is unstable and part of the energy is spent on the formation of microcracks. Originality. The method of research of the characteristics of the rock massif and protected objects used in the article indicates the possibility of a more detailed study of the mechanism of development of microcracks and their transition to unstable destruction. Practical implications. The practical value of the results lies in the information obtained to protect research objects from the negative and destructive effects of seismic pulses, as well as the ability to influence the flow and energy dissipation of explosive pulses by changing the parameters of the explosion or other engineering solutions.

Результаты первичной обработки данных инфразвуковой группы на острове Валаам

The infrasound array VALS developed in Kola Branch GS RAS has been installed in June 2016 on the Valaam Island in addition to the continuously operating seismic station VALR. The array consists of 3 spaced low-frequency microphones. The data with a sampling rate of 100 Hz is stored continuously at the acquisition computer; the timing is carried out using GPS. In addition to the acquisition system, an infrasound signal detector is installed on the computer. It works in near real-time mode and enables us to find signals and compute their back azimuths. At the end of 2018, a new version of the detector was developed at the Kola Branch GS RAS. The detector began to work much faster, which enabled us to carry out data processing for 2.5 years in two frequency ranges in a short time. The main task of the array is acoustic monitoring, the detection of infrasound events, the determination of their parameters, and the selection of events of natural origin. The data are also used (in combination with the VALR seismic station data) to locate near seismic events, especially weak ones. The analysis of the obtained data revealed the prevailing directions to the signal sources. The change of directions to sources in time was investigated, seasonal features were revealed. Acoustic events were detected in the frequency bands 1–5 Hz and 10–20 Hz, and a significant difference was found in the azimuthal distribution of events for these ranges. A joint analysis of acoustic and seismic data showed that the part of events with both acoustic and seismic components is low – it is almost completely exhausted by career explosions. It was also noted that in addition to explosions in nearby quarries (Kuznechnoye, Pitkäranta) located at a distance of 50–60 km, according to acoustic data, events corresponding to explosions at quarries located at a distance of 100 km or more were repeatedly identified.

Automated determination of internal points of the coordinate grid of the blasted rock mass

An automated method for determining the internal points of the coordinate grid of the blasted rock mass is described. It is based on the method of determining the nodal points of the coordinate grid of the blasted rock mass, which is based on taking into account the dependencies that connect the initial parameters of the blasting rock mass with the final location of the fixed points of the blasted rock mass. The determining factors are the specific height and width of the collapse, the coefficient of loosening of the rocks. The method of analysis of experimental and industrial mass explosions in quarries, methods of analytical geometry, matrix theory and linear algebra are used. For the first time in mining, an analytical method has been developed for determining the internal points of the coordinate grid of an exploded block. It includes the established functions of the movement of nodal points, components of the vectors of movement of nodal and internal points of the coordinate grid. The established dependencies allow one to determine the displacements of any point inside the coordinate grid of the blasted block from the initial coordinates of the nodal and internal points.

NORTHERN CAUCASUS

. It is reported that 59 seismic stations operated in the region in 2013. In the western and eastern parts of the region, new stations equipped with Russian digital equipment UGRA were opened: Aibga, Fisht, Karaman. The seismic network recorded 1941 earthquakes and 34 explosions in industrial quarries. 37 earthquakes were felt in the settlements of the Caucasus. The maximum shaking intensity, equal to Imax=6 on the MSK-64 scale, was felt during earthquakes on April 16 at 12h26m with КР=11.8 in the settlements of Kichi-Gamri, Mamaul, Myurego of Dagestan. Swarms of weak earthquakes with КР=4–8 were recorded in the Greater So-chi, Krasnaya Polyana areas, in Kabardino-Balkaria, and in the adjacent territory of Georgia in the area of Kazbek volcano. The area of manifestation of earthquakes with intermediate hypocenter depths, which previously belonged only to the Terek-Caspian trough (the territory of the Chechen Republic) along the diagonal Benoy-Eldarov suture zone, expanded in 2013 to the southeast and advanced under the structures of the Dagestan wedge. According to the level of seismic energy released, seismicity of the territory of the North Caucasus in 2013 characterized in accordance with the scale of the seismicity level as “background low” for the period of observations from 1962 to 2013. The strongest earthquakes occur in the connection zones of the main tectonic structures.

Investigation of the Efficiency of the Application of Water Solution of Lexol Reagent for Preparation of Pulling

A study of the effectiveness using the aqueous solution of the surfactant "Lexol" for dust suppression during mass explosions in quarries, on technological highways and use as an anti-freezing agent during transportation of bulk cargoes. The task was solved by conducting industrial studies to determine the effectiveness of reducing dust formation during mass explosions by pre-moistening the quarry blocks with the aqueous solution of surfactant "Lexol". Anti-dust reagent is an aqueous solution of glycerin component of plant origin, intended for fixing of erosion-hazardous surfaces of poly-mineral composition. Experimental explosions on the horizon of minus 360 m with the use of this reagent were carried out in the PJSC "Ingulets mining and processing integrated plant" quarry and industrial researches of dust binding on quarry roads with their watering by the aqueous solution of "Lexol". The optimal concentrations and amounts for application of the Lexol reagent to the surface of the dust and loose material during sprayingof the reagent and watering have been determined. Also, the effectiveness of using the aqueous solution of surfactant "Lexol" as an anti-freezing agent during transportation of bulk cargoes was investigated. It is determined that the reagent is economically efficient when used in the winter period of the year. In the research, the process of binding the dust particles by the surfactant "Lexol" remaining on the surface of the quarry block after drilling operations was confirmed, and which are actively involved in the overall process of forming a dust-gas cloud. At 5 % concentration of aqueous solution of the reagent "Lexol-5", the average effectiveness of dust suppression was 21 %. It is determined that the effective time of preserving the properties of the reagent on the road surface is about 10 days, and when repeated application of the aqueous solution of the surfactant "Lexol", the time of effective dust binding will increase

ПРОСТРАНСТВЕННО-ВРЕМЕННОЙ АНАЛИЗ СЕЙСМИЧЕСКОГО ВОЛНОВОГО ПОЛЯ ОТ РАСПРЕДЕЛЕННОГО КАРЬЕРНОГО ВЗРЫВА

The article presents a space-time analysis of the seismic wave from a distributed career explosion. The method of direct measurement based on the dynamic model of the wave field is used to form an image of the seismic wave field in the field of quarry explosions. The efficiency of the proposed method is shown by the example of experimental seismic recording processing. The program "Nelumbo" is used to visualize the seismic field, which on the basis of experimental seismic records allows to form an image of the wave field in the space of the hemisphere, the center of which corresponds to the position of the seismometer (registration point). The algorithm of the program "Nelumbo" is based on the Huygens – Fresnel principle and Kirchhoff's theorem. The algorithm of the program allows to allocate from record of a seismic signal frames of a certain duration and to form the image of a wave field in space of a solid angle dimension π. This approach can be used as a tool to analyze the nature of the development of disturbances in the environment and the analysis of environmental risks in the production of blasting.

Dependence of magnitude evaluation of chemical exposure characteristics at industrial careers within the boundaries of the Ukrainian Shield

Within the boundaries of the Ukrainian Shield; the main sources of induced seismicity are numerous blasting operations at open and underground minerals mining enterprises. Seismic stations of the Main Center for Special Control of the State Space Agency of Ukraine (GTSSK DSAU) and a network of seismic stations of the Institute of Geophysics of the National Academy of Sciences of Ukraine annually record thousands of industrial explosions in open quarries and mines; whose magnitude mb exceeds 0;5. Based on the analysis of seismic signals registered by the stations of the seismological network of the Main Center for Special Control; the State Space Agency of Ukraine; the ratios of magnitudes ( M ) and capacity ( Y ) of explosions were determined on industrial quarries of Kyiv; Zhytomyr; Vinnitsa; Rivne; Khmelnytsky and Cherkasy regions. According to the analysis of the dependence M = f ( Y ) for each of the investigated quarries; the average ratio between the magnitudes and the explosive capacities was calculated. This ratio can be considered fair for the conditions of the Ukrainian Shield and further used in assessing explosive work on people and the environment.

Використання водного розчину ПАР Лексол® для зв’язування пилу на автодорогах кар’єрів i зниження пиловиділення при проведенні масових вибухів

<p><span lang="EN-US">In carrying out mass explosions in quarries, a considerable amount of dust and gases is emitted into the atmosphere, more than in other technological processes of mining. The dusty cloud formed during the explosion pollutes the atmosphere not only of quarries and their industrial sites, but also the territory adjacent to them. However, the known methods and measures to reduce dust and gas emissions into the atmosphere during mass explosions have not solved this problem yet. In addition, the implementation of most methods involves certain financial costs. Therefore, the development of new ways to moisten career blocks with solutions of modern reagents produced in Ukraine is necessary and relevant. Considering the increase in the depth of quarries and, as a consequence, the extension of the length of quarry roads, the authors proved that these factors lead to an increase in the amount of dust formation from the road surface. In this regard, the solution of the problem of reducing the dust generation on the quarry roads is an important and relevant. This work is devoted to an experimental study of the determination of the effectiveness of the use of an aqueous solution of the surfactant "Leksol" to reduce dust emission during mass explosions and dust binding on the quarry roads. The problem is solved by means of industrial research to determine the effectiveness of reducing dust formation during mass explosions by pre-wetting quarry blocks with aqueous surfactant "Leksol" and binding dust on quarry roads during their watering with proposed aqueous reagent solution. The studies have confirmed the process of binding with surfactant "Leksol" of fine dust particles remaining on the surface of the quarry block after drilling on the surface thereof, and are actively involved in the overall process of formation of dust and gas cloud. At the concentration of the aqueous solution of the anti-dust reagent "Lexol-5" 5%, the average efficiency of dust suppression was 21%.</span></p>

Chances and limits of single-station seismic event clustering by unsupervised pattern recognition

Automatic classification of local seismic events which are only recorded at single stations poses great challenges because of weak hypocentre constraints. This study investigates how single-station event clusters relate to geographic hypocentre regions and common source processes. Typical applications arise in local seismic networks where reliable ground truth by a dense temporal network precedes or follows a sparse (permanent) installation. The seismic signals for this study comprise a 3-month subset from a field campaign to map subduction below northern Chile (PISCO ’94). Due to favourable ground noise conditions in the Atacama desert, the data set contains an abundance of shallow and deeper earthquakes, and many quarry explosions. Often event signatures overlap, posing a challenge to any signal processing scheme. Pattern recognition must work on reduced seismograms to restrict parameter dimensionality. Continuous parameter extraction based on noise-adapted spectrograms was chosen instead of discrete representation by, for example, amplitudes, onset times or spectral ratios to ensure consideration of potentially hidden features. Visualization of the derived feature vectors for human inspection and template matching algorithms was hereby possible. Because event classes shall comprise earthquake regions regardless of magnitude, clustering based on amplitudes is prevented by proper normalization of feature vectors. Principal component analysis is applied to further reduce the number of features used to train a self-organizing map (SOM). The SOM will topologically arrange prototypes of each event class in a 2-D map. Overcoming the restrictions of this black-box approach, the arranged prototypes could be transformed back to spectrograms to allow for visualization and interpretation of event classes. The final step relates prototypes to ground-truth information, confirming the potential of automated, coarse-grain hypocentre clustering based on single-station seismograms. The approach was tested by a twofold cross-validation whereby multiple sets of feature vectors from half the events are compared by a one-nearest neighbour classifier in combination with an Euclidean distance measure resulting in an overall correct geographic separation rate of 80.5 per cent.

A catalogue of non-tectonic earthquakes in central-eastern Italy

<p>Quarry explosions and other non-tectonic signals can contaminate seismic catalogues, especially in areas where dense seismic networks allow to detect even low energy events. This paper presents the algorithm adopted for the discrimination of non-tectonic earthquakes in central-eastern Italy, an area with a high rate of events of this kind (4500 were recorded in the 1996-2012 period). Starting from an empirical classification based on the analysis of areas in which the ratio between daytime and nighttime events is strongly anomalous, a waveform similarity approach allows to simplify the procedure of detection making the final classification more robust. The resulting catalogue of non-tectonic earthquakes (quarry blasts and other anomalous signals) is a useful tool for anyone wanting to carry out a careful analysis of the tectonic seismicity of central-eastern Italy.</p>

Effect of industrial explosions on the stability in rock mass with cavities

The paper substantiates the conditions of seismic stability in the rock mass with cavities, on which protected objects are located, under constant seismic effects of mass explosions in quarries. Based on the ray-tracing method, a mathematical model of the interaction between longitudinal and transverse waves with a spherical cavity has been developed. An algorithm has been elaborated for determining the total static and dynamic loads along the spherical cavity perimeter from seismic explosion waves falling on the interface. The regularities of joint action of static loads have been determined, when located above the objects cavity, with allowance for the effect of the mass of cavity ceiling, the mass of the protected object above it and dynamic loads in the rock mass, and under the plane wave front fall on the cavity from different directions. The dependences of the change of total stresses referred to the incident wave stress at the interface of the rock mass and the cavity depending on the coordinate on its surface have been set. It has been established that the most dangerous points of cavity surface, in which destruction is likely to occur, are the cases when the seismic wave front falls on the cavity from the bottom directions typical for blasting operations in deep quarries. Under the arbitrary angles of the wave incidence on the cavity the stresses rearrange along the perimeter, which under different circumstances might lead to the mass breach and the fall of the protected objects, located above it, under the ground

The pattern of diurnal periodicity of weak earthquakes in Iran

The catalogue of earthquakes recorded in Iran during 2006–2010 by a dense network of digital telemetric seismic stations is analyzed. The spectrum of the time series of these earthquakes contains a sharp maximum at 24 h. The corresponding curve of diurnal periodicity constructed by the superposed epoch method has a clear double-peak maximum near noon(11 a.m.-5 p.m. local time), which exceeds the level of seismic activity observed during the rest time of the day by a factor of 3-3.5. In the same time interval, the average hourly magnitudes of seismic events sharply drop from M = 2.15 to M = 1.95. The ratio of the normalized number of earthquakes in the daytime to those at other times of the day, which was determined within a moving window half a square degree in size, has seven distinct compact spatially isolated maxima whose magnitudes attain several dozens to a hundred units. These maxima are probably caused by industrial activity, such as road building and quarry explosions. We also note the presence of the weekend effect when the daytime maximum in the weekly curve of diurnal variations in seismic activity almost completely disappears on Friday, which is the weekend in Muslim countries. At the same time, elimination of the supposed noise component from the catalogue by the approved technique changes nothing for the daytime maximum in the daily pattern of earthquakes in Iran. In order to account for this inconsistency, we suggest invoking additional information on the technogenic seismicity and considering weak earthquakes induced by quarry explosions and vibrations of industrial machines, in particular, power units of numerous hydroelectric power stations distributed over the territory of Iran.