Characterization of rock thermophysical properties and factors affecting thermal conductivity−A case study of Datong Basin,China

Rock thermal physical properties play a crucial role in understanding deep thermal conditions,modeling the thermal structure of the lithosphere,and discovering the evolutionary history of sedimentary basins.Recent advancements in geothermal exploration,particularly the identification of high-temperature geothermal resources in Datong Basin,Shanxi,China,have opened new possibilities.This study aims to characterize the thermal properties of rocks and explore factors influencing thermal conductivity in basins hosting high-temperature geothermal resources.A total of 70 groups of rock samples were collected from outcrops in and around Datong Basin,Shanxi Province.Thermal property tests were carried out to analyze the rock properties,and the influencing factors of thermal conductivity were studied through experiments at different temperature and water-filled states.The results indicate that the thermal conductivity of rocks in Datong,Shanxi Province,typically ranges from 0.690 W/(m·K)to 6.460 W/(m·K),the thermal diffusion coefficient ranges from 0.441 mm^(2)/s to 2.023 mm^(2)/s,and the specific heat capacity of the rocks ranges from 0.569 KJ/(kg·℃)to 1.117 KJ/(kg·°C).Experimental results reveal the impact of temperature and water saturation on the thermal conductivity of the rock.The thermal conductivity decreases with increasing temperature and rises with high water saturation.A temperature correction formula for the thermal conductivity of different lithologies in the area is proposed through linear fitting.The findings from this study provide essential parameters for the assessment and prediction,development,and utilization of geothermal resources in the region and other basins with typical high-temperature geothermal resource.

Environmental Investigation and Evaluation of Land Subsidence in the Datong Coalfield Based on InSAR Technology

Heavy mining of Jurassic and Carboniferous horizontal coal seams in the Datong coalfield has seriously affected the local geological environment, which is mainly manifested by such geohazards as soil avalanches, landslides, mudflows, surface subsidence, surface cracks, surface solid waste accumulation and surface deformation. More seriously, coal mining causes groundwater to leak. Overpumping of groundwater has resulted in substantial land subsidence of the urban area in Datong City. Based on the previous geo-environmental investigation in the work area, the authors used radar remote sensing techniques such as InSAR （synthetic aperture radar interferometry） and D-InSAR （differential synthetic aperture radar interferometry）, supplemented by the optical remote sensing method, for geo-environmental investigation to ascertain the geo-environmental background of the Datong Jurassic and Carboniferous-Permian coalfield and evaluate the effects of the geohazards, thus providing a basis for the geo-environmental protection, geohazard control and prevention, land improvement and optimization of the human environment. In this study 8 cog-nominal ERS-1/2 SAR data frames during 1992 to 2003 were used, but the following processing was made： （1） the multitemporal SAR magnitude images were used to interpret the geological structure, vegetation, microgeomorphology and drainage system; （2） the multi-temporal InSAR coherent images were used to make a classification of surface features and evaluate the coherence change due to coal mining; and （3） the multi-temporal cog-nominal SAR images were used to complete D-InSAR processing to remove the information of differential deformation areas （sites）. In the end, a ten-year time series of differential interferograms were obtained using the multi-temporal cog-nominal SAR images. In the tests, 84 deformed areas （sites） were obtained, belonging to those in 1993-1996, 1996-1997, 1997-1998, 1998-2001, 1998-2002 and 2001-2003 respectively. Of the 84 areas, 44 are mining subsidence ones, 23 urban subsidence ones and 17 landslide subsidence ones. They cover a total area of 1824.4 km^2, equivalent to the area of the whole Datong coalfield. Then an accurate evaluation was made on the geo-environment of the Datong coalfield. The tests show that InSAR is now the only feasible technical means for making one all-weather, real-time measurement of a coal mining land subsidence area covering up to 10,000 km^2 to subcentimeter resolution. This study is a successful application of InSAR in the investigation and evaluation of land subsidence, especially in coal mining areas.

Hydrogeochemistry of River Water in the Upper Reaches of the Datong River Basin,China:Implications of Anthropogenic Inputs and Chemical Weathering

This research investigated anthropogenic inputs and chemical weathering in the upper reaches of the Datong River Basin,a tributary of the upper Yellow River,NW China.Multiple approaches were applied to data from 52 water and 12 soil samples from the Muli,Jiangcang,and Mole basins to estimate the chemical component concentrations and to analyze hydrochemical characteristics,distribution patterns,and origins in this coal mining-affected river basin.Coal mining has enhanced the weathering of the lithosphere in the study region.The total dissolved solids in the river range from 145.4 to 701.9 mg/L,which is higher than the global average for rivers.Ion concentration spatial distributions increase around mining areas.River geochemistry is mainly controlled by coal mining activity,carbonate weathering,and silicate weathering,with variances of 33.4%,26.2%,and 21.3%,respectively.Ca^(2+),Mg^(2+),and HCO_(3)^(-)are mainly due to the dissolution of carbonate minerals(calcite>dolomite);Si and K+are mainly from potassium(sodium)feldspar weathering;and Na+and SO_(4)^(2-)mainly from coal mine production.A conceptual model of the river water ion origins from the study area is presented and management implications for improving the adverse effects of coal mining are proposed.These results provide an important standard reference for water resource and environmental management in the study region.

Did the MS 7.0 Lushan earthquake dynamically trigger earthquakes in the Datong volcanic region(Shanxi Province)?

Immediately following the Ms7.0 Lushan earthquake on April 20, 2013, using high-pass and low- pass filtering on the digital seismic stations in the Shanxi Province, located about 870-1,452 km from the earthquake epicenter, we detected some earthquakes at a time corre- sponding to the first arrival of surface waves in high-pass filtering waveform. The earthquakes were especially noticed at stations in Youyu （YUY）, Shanzizao （SZZ）, Shanghuangzhuang （SHZ）, and Zhenchuan （ZCH）, which are located in a volcanic region in the Shanxi Province,but they were not listed in the Shanxi seismic observation report. These earthquakes occurred 4-50 rain after the passage of the maximum amplitude Rayleigh wave, and the periods of the surface waves were mainly between 15 and 20 s following. The Coulomb stresses caused by the Ray- leigh waves that acted on the four stations was about 0.001 MPa, which is a little lower than the threshold value of dynamic triggering, therefore, we may conclude that the Datong volcanic region is more sensitive to the Coulomb stress change. To verify, if the similar phenomena are widespread, we used the same filtering to observecontrastively continuous waveform data before, and 5 h after, the Ms7.0 Lushan earthquake and Ms9.0 Tohoku earthquake in 2011. The results show that the similar phenomena occur before the earthquakes, but the seis- micity rates after the earthquakes are remarkably increased. Since these weak earthquakes are quite small, it is hard to get clear phase arrival time from three or more stations to locate them. In addition, the travel time differences between P waves and S waves （S-P） are all less than 4 s, that means the events should occur in 34 km around the stations in the volcanic region. The stress of initial dynamic triggering of the Ms9.0 Tohoku earthquake was about 0.09 MPa, which is much higher than the threshold value of dynamic triggering stress. The earthquakes after the Ms9.0 Tohoku earthquake are related to dynamic triggering stress, but the events before the earthquake cannot be linked to seismic events, but may be related to the back- ground seismicity or from other kinds of local sources, such as anthropogenic sources （i.e., explosions）. Using two teleseismic filtering, the small background earthquakes in the Datong volcanic region occur frequently, thus we postulate that previous catalog does not apply bandpass filter to pick out the weak earthquakes, and some of the observed weak events were not triggered by changes in the dynamic stress field.

The Datong earthquake and its anomalous tilt Field

In this paper, the similarity and the meanings of anomalous pattern of entropy for tilt tide amplitude factor, the distribution of entropy and dimension for tilt velocity, the similarity and relationships for long-period tilt deformation and earthquake migration are demonstrated. The deformation wave and its meanings have also been explained. The authors explored the relationships between distribution of similar pattern and epicenter. The possibility of prediction for next earthquake epicenter has also been explored based on the combining tilt field and earthquake activity.

The fracture characteristic of the 1989 Datong-Yanggao earthquake sequence

This paper, first, analyzed the seismic activity patterns of the Datong-Yanggao earthquake sequence by 4 stages,finding that three times earthquakes of Mis were located in a same NNE seismically active zone and two times located in 2 NWW seismically active zones. Then the focal-mechanism solutions of 12 earthquakes of M≥4 and 114 earthquakes of M≥1. 0 in various zones were obtained, a tectonic analysis was made for these data, the obtained fracture characteristic of this sequence is: the conjugate fracture combination with the NNE right lateral faults as its trunk and the two NWW left lateral faults as its branches. Finally, it is pointed out that there is an obvious difference between the seismic fracture and the tensile dip-slip tectonic activity of the main body of the seismic region.

Development of a New Yak Breed Through Utilization of Wild Yak Genetic Rsource-seral Technologies for the Development of the Datong Yak Breed

On the Datong Yak Breeding Farm of Qinghai Province(Datong farm), the scientists of the Lanzhou Institute of Animal Science and Veterinary Pharmaceutics of Chinese Academy of Agricultural Sciences, in collaboration with others,explored the possibility to cross wild yak bulls with domestic yak cows in the past 20years and a new yak breed, the Datong yak, has been developed.

DATONG MINING BUREAU——THE LARGEST COAL ENTERPRISE IN CHINA

The Datong Mining Bureau, locatedin the southwest of Datong, famousfor its history and culture, is thelargest coal enterprise in China. It has 200,000staff and workers and fixed assets of RMB9.81 billion. Its annual output of raw coal is37 million tons, and its sales income totalsRMB 4.62 billion, of which RMB 1.18 billioniS tax and profits.

1989 Datong-Yanggao Earthquake with Ms=6.1

In this paper,the basic conditions and characteristics of the Datong-Yanggao earthquake are described in detail.The type of the earthquake,the aftershock activity,the earthquake trend,the characteristics of damage are analyzed and discussed.This earthquake belongs to a sequence of earthquake swarm type and is of the concentratedly occurring characteristics of several main shocks in a time sequence,and the aftershock activity was normally attenuated.Because of the unreasonable design of buildings and repeated vibration by several destructive main shocks within a short period,the damage in the high intensity region was aggravated.The analysis and the prediction procedure of the 1991 Datong-Yanggao earthquake(Ms=5.8)are also briefly given.

The Making of an Inclusive Museum:The Example of‘General Branch Museum System’of Datong Museum,China

A museum is a not-for-profit,permanent institution in the service of society that researches,collects,conserves,interprets and exhibits tangible and intangible heritage.In order to effectively integrate public cultural resources,many museums at home and abroad have begun to explore general branch museum system.This mode develops rapidly in China and forms many models.However,the general branch museum system of each museum has its own characteristics.Based on this,this paper mainly introduced the example of“general branch museum system”of Datong Museum,China.For the time being,Datong Museum is implementing“general branch museum system”.Datong Museum is located in Shanxi Province,China.It is a comprehensive museum and now it is a national first-level museum.There are more than 170,000 cultural relics in Datong Museum.Besides the general one,the other nine branches have opened to the public.It is different from the National Museum Wales,the Smithsonian Institution,and the Cathedral Museum Complex in Toscana District.Led by theme of integration of the main,not only each of the nine branch museums bears its own specific theme and distinct characteristics,but they also link and complement each other.In future,we will further explore the exhibitions of other thematic displays to tell the complete history of Datong,and supplement the untold historical stories,as well as boost recognition of cultural identity and cultural confidence of the public.

System integration and innovation of operating 20 kt combined heavy-haul train on Datong-Qinhuangdao line

Datong-Qinhuangdao line, as the first electrified double-track heavy-haul line dedicated to coal transport in China, extends from Datong in the west, and reaches Qinhuangdao in the east, opened to traffic in December, 1992, totaling 653 km with the designed annual traffic volume of 1×108 t. In order to meet the demands of national economic development, the transport capacity of the line must be enhanced greatly. Depending on independent innovation, MOR, for the first time in the world,realizes the integration between GSM-R and Locotrol, the integration between 800 MHz digital radio and Locotrol, and the integration between a single set of Locotrol and SS4 locomotive. Meanwhile, CR develops equipment portfolio for heavy-haul through combining 2 high power locomotives of HXD series (means harmony) with controllable EOT. Relying on integration and innovation, it succeeds in operating 20 kt-level combined heavy-haul train on Datong-Qinhuangdao line, which tripled the annual traffic volume of the line from 1×108 t in 2002 to 3×108 t in 2007.

A Preliminary Study on the Datong Fault Belt

The Datong fault belt is a NE trending fault in the northern Qinghai-Xizang (Tibet) Plateau and controls the boundary of the Xining Basin and Datong Basin. It consists of the Maziying-Miaogou (F_1) fault and the Laoye Mountain-Nanmenxia fault (F_2). There is obvious displacement in vertical direction along the belt. The field investigation results show that this belt has long-term activity. There are several meters long crushed zones and veins along the fault side in the basement rock. On the fault section,the Cambria system thrusts over the red-brick-colored Quaternary Period gravel,and there is a fault gouge of several centimeters thick developed on the fault plane. The fault gouge date (ESR) on the fault plane is 610±61ka. The covering deluvial loess is not dislocated,and the OSL result is 14.6±1.5ka. So it can be concluded that the fault belt was active in the middle Pleistocene,but inactive in the late Pleistocene according to the age data and geomorphologic features. Interior formations of the Datong basin features fold with the major axis orienting northwest. According to the relation of fault and fold deformation,Datong fault is a transversal tear,which is due to uneven compression of the folds in different parts and NNE trending regional compressive stress. It is common among the NE trending faults in the northeast of Qinghai-Xizang (Tibet) Plateau. These NE trending faults aren't large,and most are located in the active plate. They are all nearly vertical to the axis of the folds and compressive basins.

Focal Fault of the 1999 Datong M_S5.6 Earthquake in Shanxi Province

Several earthquakes with M S≥5.0 occurred in the Datong seismic region in 1989, 1991 and 1999. The precise focus location of the earthquake sequence was made by the records of the remote sensing seismic station network in Datong. Using that data together with macro-intensity distribution and focal mechanism solutions, we analyze the difference among three subsequences. The results show that the focal fault of the 1999 M S5.6 earthquake was a NWW-trending left-lateral strike-slip fault. It is 16 km long and 12 km wide. It developed at the depth of 5 km and is nearly vertical in dip. The two previous earthquake subsequences, however, were generated by activity along NNE-trending right-lateral strike-slip fault. It can be found that the rupture direction of the 1999 earthquake has changed. It is generally found that a rupture zone has more than two directions and has different strength along these two directions. The complicate degree of focal circumstance is related to the type of earthquake sequences. There is the NE-trending Dawangcun fault and the NW-trending Tuanbu fault in the seismic region, but no proof indicates a connection between focal faults and these two tectonic faults. The feature that focal faults of three subsequences are strike-slip is different from that of the two tectonic faults. It is suggested that the 1999 earthquake subsequence was possibly generated by a new rupture.

Correlation Analysis of Gridding of Earthquakes in Datong and Its Surrounding Areas and Implication for Earthquake Prediction

On the basis of the earthquake ( M_L ≥3. 0 ) catalog in North China from 1970 to 2009,the pattern of temporal and spatial distribution of medium-small earthquakes in Datong and its surrounding areas is studied by correlation analysis with a focus on its anomaly before moderate and strong earthquakes. With different spatial scales,temporal scales and time steps, the spatial distribution of earthquakes is converted to a sequence, then the correlation coefficients between the spatial distribution of medium-small earthquakes in a long-term and a longer time are calculated for the analysis of anomalies before moderate and strong earthquakes. In the study region center on the epicenter of the 1989 Datong-Yanggao earthquake ( M_S 5. 9 ) within a radius of less than 0. 8°,with the time length of 3600 days,the longer time length of 3700 days,and the time step of 100 days, the correlation coefficient from 1980 to 2009 is steady between 0. 94 and 1. 00,but there were anomalies with values less than 0. 94 in the 2 years before the 1989 Datong-Yanggao earthquake ( M_S 5. 9 ) , the 1991 Datong earthquake ( M_S 5. 8 ) and 1999 Hunyuan earthquake ( M_S 5. 6 ) , which indicates the spatial distribution of a medium-small earthquake is very different from steady background seismicity. The implication for earthquake prediction from the anomaly of the correlation coefficient is also discussed with the three conclusions: ( 1 ) Before moderate and strong earthquakes in Datong and its surrounding areas,the obvious change of spatial distribution patterns of medium-small earthquake can be a kind of seismic precursor of the 2-year time scale for the prediction of an earthquake's time. ( 2 ) As the study region is restricted within a radius of less than 0. 8°,the result of correlation analysis is also good for the prediction of an earthquake's location. ( 3 ) The method of correlation analysis in this paper helps recognize the anomaly of spatial distribution of medium-small earthquake.