Geology Of Area Research Articles

Effect of Meteorological Factors on PM<sub>10</sub> Concentration in Hanoi, Vietnam

According to the Ministry of Natural Resources and Environment, Hanoi city is currently facing the increased air pollution, especially particulate matter. This study examines the influence of meteorological factors including temperature, humidity and wind speed on PM10 concentration in Hanoi. The data used in this study include 24-h PM10 concentration data, hourly temperature, humidity and wind speed data in 2018 at three automatic air monitoring stations under Vietnam Environment Administration and Hanoi Natural Resources and Environment Department. The SPSS statistical analysis tools are utilized to analyze the correlation between PM10 concentration and meteorological factors through the Spearman (r) correlation coefficient. Additionally, the Independent-Sample T-Test is also employed to assess the difference in PM10 concentration in the period between dry season (from October to March) and wet season (from May to September). The results show that there is a trend of seasonal variation of PM10 concentration. Specifically, PM10 concentration recorded a higher value in winter and lower in summer. Different correlations between air pollutants and meteorological factors were also observed. PM10 concentration was inversely correlated (r 10 concentration during dry and wetseason. This outcome has confirmed the important role of meteorological factors in the formation of air pollution with large variations in different seasons and geological areas.

INSIGHT INTO SEISMIC REFRACTION AND ELECTRICAL RESISTIVITY TOMOGRAPHY TECHNIQUES IN SUBSURFACE INVESTIGATIONS

Geophysical subsurface investigations use the principles of physics to unravel intrinsic Earth’s subsurface features and nature of the underlying geology. Over the past two decades, the use of Seismic Refraction Tomography (SRT) and Electrical Resistivity Tomography (ERT) for subsurface investigations has greatly improved the quality of acquired data for two- and three-dimensional (2D and 3D) surveys. SRT employs more shotpoints and receivers than the conventional seismic refraction for its imaging technique. ERT uses automated multi-electrode array systems to improve the confidence of large and dense data collection. SRT and ERT techniques use powerful inversion algorithms to achieve high resolution subsurface inversion models for resolving subsurface characteristics and geological conditions over a complex and larger area that may be difficult with the use of their conventional methods. The 2D and 3D inversion models (tomograms) generated from the field data sets of these techniques efficiently ameliorate inaccurate subsurface boundaries and structural delineation with higher depth resolution, especially the 3D inversion models for areas of complex geology. These state-of-the-art techniques have extensively been used for groundwater, environmental, engineering and mining investigations among others. This study provides insight from theories to data inversion techniques for the known tomography techniques (SRT and ERT) in use for subsurface investigations.

Technical Innovation of Ultra-Deep Well Drilling Rig and Its Development Trend

8000-meter drilling rig and quadruple joint 9000-meter drilling rig have been developed for ultra-deep and complex wells of the complicated geological structure area in Tarim Basin, China. The key components of the drilling rigs are redesigned and innovated, including optimization of the high bearing capacity derricks and substructures and a completely new design of integrated single shaft drawworks with the compacted strand wire rope. The rotary table and its driving device with larger torque and load capacity, the high-pressure drilling pump with a high power, intelligent top drive system, casing running device with good compatibility, and automated pipe handling system are equipped. Field application shows that 8000 meters drilling rig, compared with the conventional 9000-meter drilling rig, can save equipment procurement costs by about 20%, reduce drilling operational costs 37%. In addition, the quadruple joint 9000-meter drilling rig can reduce the tripping time by more than 20%, and that the pressure is difficult to control in the complicated formation by conventional drilling rigs can be avoided to a certain extent. At the end of this paper, the advantages and the problems to be solved urgently of the ultra-deep well drilling rigs are expounded.

Ecological vulnerability assessment of geological disaster-prone areas: a case study of Shanyang County in Shaanxi Province, China

The geological environment in Qinling-Dabashan Areas is fragile due to Meteorological and hydrological conditions, topographic features, geological structures, stratum lithology and human activities. This article selected Shanyang County, a disaster-prone area in Qinling-Dabashan Areas, as the study area, based on the analysis of present situation and the driving factors of the ecological vulnerability, and selected 16 indicators to construct the evaluation index system from three aspects sensitivity, resilience and pressure. The results show that: The proportion of areas with moderate vulnerability and above in Shanyang County is 61.4%, and the overall ecological vulnerability is at a moderate to high level. Severe and extremely vulnerable areas are obviously geologically neutral, mainly distributed in the northern, central and northern regions and the central and eastern regions. Areas with high ecological vulnerability are concentrated in rivers with frequent human activities and low mountain areas with serious soil erosion. The ecological vulnerability in the east is higher than that in the west; in north-south direction, it is inverted U-shaped, and the south is slightly higher than the north; the central ecological vulnerability is the highest throughout the region.

Classifying the geology journals by editorial board interlocks

Academic journals are important carriers of scientific activities, important academic communication media, and channels in the process of scientific development, and an important research unit in the structure and classification system of scientific knowledge. In this paper, we use the interlocking editorship theory to construct a complex network of important journal editors of geology, analyze the degree of intimacy between journals, and use visual means to classify geological journals according to disciplines, and show the branches and subject areas of geology. On this basis, it reveals the development and evolution law of the discipline of geology and the structural characteristics of cross-fusion.

Evaluation of Engineering Properties of Rocks and Soils of a Part of the Southwestern Area of Mosul City

The main task of this research is to study the distribution of the engineering properties of rocks and soils at the part of the area located in the south western Mosul City. The relationship of these aspects with the geology of the area and its importance of preliminary designs of structures has been studied as well. The data are collected from the reports on geological investigations and engineering laboratory testing of the proposed third canal of the South Jazirah Irrigation Project. Most of the land region is covered by the soil, that thickness ranges between 0 and nearly 20 meters and penetrated by boreholes reaching to the subsurface of evaporating, carbonate and clastic rocks of Fat’ha and Injana formations. Data processing and evaluation of 66 boreholes are used to find the statistical relations among them. The studied area was divided into four secondary regions ( northern, southern, western and eastern). The studied engineering tests have been included the physical, mechanical and dynamic properties, which have generally low values in most areas. The distribution of the means of all properties that used in the assessment of the properties of soil and rock with the relation of the geological area has shown good properties when approaching to the anticlines of Allan, Hamam Al-Aleel, Nwaigeet, Kaliyan, Al- Shorah, Kassab and Addayah. The study shows that the relationship between the liquid limit and plasticity index is good for all data. The relationship between moisture content and dry density is also good however, the relationship between moisture content and the ratio of dry and saturated density is better, because of the higher relationship between porosity and moisture content. The relationship between bulk density and the velocity of longitudinal waves reveales a sharp reduction of the velocity values of longitudinal waves with reducing of the bulk density values. While, the relationship between bulk density and shear wave velocity is better due to the effect of shear waves withthe porosity more than that of longitudinal waves. In order to confirm that, it has been found that the relationship between the shear waves velocity and moisture content is the best in contrast with a velocity of longitudinal waves. Generally, the relation between dynamic properties with moisture content has a higher correlation coefficient with that of the density. The distribution of most of the engineering properties has shown low values in eastern and western region in contrast with the northern and southern ones.

Improved Interpretation of Deep Seismic Reflection Data in Areas of Complex Geology Through Integration With Passive Seismic Data Sets

AbstractThe Capricorn Orogen records the Paleoproterozoic amalgamation of the West Australian Craton. 2‐D deep‐seismic reflection data across the Orogen are difficult to interpret due to the complex geology, and fundamental questions remain about the nature of the basement in the northern part of the Orogen. Passive seismic data have been collected along a 250‐km‐long transect across the central part of the Capricorn Orogen. The passive seismic recordings utilized teleseismic arrivals to construct a velocity section using the receiver function common conversion point method and to estimate crustal thickness and Vp/Vs using the H‐k method. A shear velocity cross section was created using ambient noise‐based methods. An integrated interpretation of all the seismic data sets shows that basement in the central Capricorn Orogen comprises a series of distinct terranes. These are recognized based on changes in crustal reflectivity, velocity and Vp/Vs. We interpret these terranes as originating from an island arc caught in the collision between the Glenburgh Terrane and the Pilbara Craton as part of the 2215–2145 Ma Ophthalmia Orogeny. Although passive seismic data do not have the resolution of reflection data, the information gained from the passive data places important constraints on the reflection interpretation and provides complementary information about changes in crustal composition. We propose that passive seismic data represent a cost‐effective complementary geophysical data set that can greatly assist with the interpretation of deep reflection sections in areas of complex geology.

New Challenges: From Physics to Medicine

The current state of neutron research at the IR-8 reactor is considered and it is shown that the research is focused on two main avenues: comprehensive radiation diagnostics for the sake of those knowledge domains which have not used it before and research of the structure of material under extreme conditions (high pressures, strong magnetic fields, and irradiation). Case studies are given in the areas of materials technology, geology, paleontology, archaeology, and medicine, as well as studies of materials under thermobaric impact and self-radiation. The possibilities of a combination of different experimental techniques are discussed.

STUDY OF STRESSES ON THE CREPE OF WELLS UNDER ROCKS PRESSURE

The article considers the spectrum of issues of development of deposits. We give a brief description of the structure: their geological structure, information about the properties of productive rocks (reservoirs). Considerable attention is paid to the technical means and technologies for the construction of wells in the operational and geological exploration area. The article touches upon the issues of field development, aspects of safety and environment.

LIGHT CEMENT MIXTURES

Lightweight cement mixtures with high technological properties based on the standard well cement Portland cement ПЦТІ-100 and building cements ПЦІ-500-Н, ШПЦ Ш/А-400 with a light impurity-acid fly ash of thermal power stations were developed and investigated. The minimum density of cement mortars based on the developed mixtures is, respectively, 1 460–1 530 and 1 580–1 650 kg/m3, while ensuring the high quality of other technological properties of cement mortar and stone. The development and selection of optimal recipes for new lightweight cement mixtures has been carried out. The results of the work are of practical use in cementing oil and gas wells in complex mining and geological conditions in geological exploration areas and industrial hydrocarbon fields.

Study of Converted-Wave Modeling: AVO Application for Shallow Gas Models

The application of converted-wave seismic method in hydrocarbon exploration has increased significantly. Since the conventional seismic ceases to provide an adequate result in complex geology area and it provides an ambiguous brightspot response. The main principle is that an incident P-wave produces reflected and converted P and SV wave when the downgoing P-wave impinges on an interface. Converted-wave seismic uses the multicomponent receiver that records both of vertical component and horizontal component. The vertical component is assumed to correspond to the compressional PP wave and the horizontal correspond to the PS converted-wave. In this research, a synthetic model with the shallow gas and the salt dome below are constructed. The purpose of this study is to analyze the brightspot due to the presence of shallow gas and its effect to the quality of PP and PS wave reflection below the gas zone. To achieve the goal, both vertical and horizontal seismic data processing are performed. In horizontal data processing, the best gamma function (Vp/Vs) value is estimated to produce the better and reliable image. The result shows that the brightspot response in conventional data doesn’t exist in converted-wave data and the imaging below the gas zone in converted-wave data is better than the conventional due to the attenuation and diffraction effect that caused by gas column. Processing is followed by AVO analysis to compare the AVO response of PP and PS data in characterizing gas reservoir. Both PP and PS AVO curve shows the consistency with synthetic AVO from well data. Gas reservoir is a class 1 AVO anomaly with positive intercept and negative gradient on PP data. However, PS AVO curve does not refer any anomaly. It is because S-wave is not sensitive to the existence of rock saturant.

Computation of residual statics in complex geological areas using simulated annealing method based on minimization of objective function

Computation of residual statics in complex geological areas using simulated annealing method based on minimization of objective function

Study of aquatic ecological regions using fish fauna and geographic archipelago factors

An evaluation of ecological integrity is required for ecosystem conservation and restoration. The ecological region, or “ecoregion”, has been adopted as a unit of geological area to enable a comparison of the ecological integrity of different regions. The delineation of an ecological region is difficult in countries in East Asia, including Japan because of complex topographies (i.e., several peninsulas and islands) and fauna that are very finely delineated based on climate or geology. Therefore, it is important to appropriately determine the ecoregions when determining their biological integrity and comparing it among that of other ecoregions. I attempted to delineate an ecological region of the Japanese archipelago based on the similarities among fish fauna by integrating the information on fish fauna that was collected by the researchers and the national government and local governments. In addition, quantitative analyses to investigate the relationship between fish fauna classification and meteorological and geographical factors were conducted to discuss the factors that influence fish fauna classifications. The archipelago was classified into 15 fish fauna groups, and the results of these grouped classifications were closely related to the process by which the Japanese archipelago was formed, the ocean current in its coastal waters, and the connection of the water system to the glacial age. Our findings suggest that rivers within geographical areas that are different from those within the Japanese archipelago might have different fish fauna classifications based on our results and potential fish fauna depending on the characteristics of the watershed, such as the scale of the floodplain, river conflicts, or river formation process. By applying the results of our fish fauna classification, we are able to make a comparison of the biological integrity of fish fauna among different watersheds for managing the river environments or establishing conservation policies.

A Statistical Constitutive Model considering Deterioration for Brittle Rocks under a Coupled Thermal-Mechanical Condition

Due to active actions of groundwater and geothermal, the stability of underground engineering is important during geological structure active area. The damage mechanical theory and statistical mesoscopic strength theory based on Weibull distribution are widely used to discuss constitutive behaviors of rocks. In these theories, a statistical method is used to capture mesoscopic properties of rocks in order to generate a realistic behavior at a macroscopic scale. Based on the above theories, this paper aims at establishing a constitutive relation of brittle rocks under thermal-mechanical coupling conditions. First, a statistical damage constitutive model was established by considering the thermal effects and crack initiation strength. Subsequently, the parameters of the model were determined and expressed according to the characteristics of stress-strain curve. Third, the model was verified by conventional triaxial experiments under thermal-mechanical actions, and the experimental data and theoretical results were compared and analyzed in the case study. Finally, the physical meaning of the parameters and their effects on the model performance were discussed.

Compositional characterization of fine sediments and circulating waters of landslides in the southern Apennines – Italy

Several studies in the last several years have shown that slope stability and the physical–mechanical properties of sediments can be influenced by their granulometrical, chemical and mineralogical characters and circulating water chemistry, which highlights the importance of studying these processes using a multidisciplinary approach. Two landslides, in a well-known geological area in the Southern Apennines impacted by many landslides, were studied to integrate geological and geomorphological surveys and geotechnical tests with the compositional characterization of the sediments and circulating waters and through a careful definition of the tipology and intensity of the weathering processes.Pliocene clays and Oligocene slates affected by the studied landslides were characterized for mineralogical, chemical and grain-size composition and these compositional characters were compared with their physical (Atterberg limits, plasticity, activity) and mechanical (friction angle, cohesion, residual shear strength) properties. These properties were determined using distilled water, waters circulating in the landslide sediments and saline solutions that amplify seasonal chemical variations. The compositional and physical-mechanical properties of the sediments were compared with the slip and low deformation zone positions, detected in situ from inclinometer measurements, in order to identify any anomalies in the weak zones along the stratigraphic column.The results showed some correlations between the compositional characters of sediments (grain size, mineralogy and geochemistry) and the slip zone position, and highlighted that the chemistry of the circulating waters can modify certain physical-mechanical behaviours. However, the magnitude and modalities of such influences depends strongly on the geological history and lithotypes involved in the sliding. The Pliocene clay landslide was found to have several slope instability risk factors, such as kaolinite content and water salinity, while the physical-mechanical properties of the Oligocene slates were demonstrated to be less sensitive to sediment and water compositional characters.Finally, significant correlations were detected between the position of the slip zone and the degree of sediment chemical alteration using a new weathering index specifically designed for the sediments studied.These results demonstrate that the study of landslides must not ignore the compositional characterization of the sediments and waters, as certain chemical or mineralogical features can represent important risk factors contributing to the worsening of the slope stability and the triggering of the slip.

Spectral analysis of the Cerean geological unit crater central peak material as an indicator of subsurface mineral composition

The dwarf planet Ceres is a heavily cratered rocky body, and complex craters with a central peak are widely observed on its surface. These types of craters form when a large body impacts the surface, generating extreme temperatures and pressures. During the impact event a large volume of rock is raised from the subsurface and a central uplift is formed. The material composing the central uplift is called crater central peak material (ccp) and the spectral analysis of such geologic areas can provide information about the composition of Ceres’ subsurface. Reflectance spectra of 32 ccps, acquired by the VIR spectrometer on board the NASA/Dawn spacecraft, were analyzed and shows absorption bands located at about 2.7, 3.1, 3.4 and 4.0 µm which are also common on the Cerean surface. These absorptions are related, respectively, to Mg-phyllosilicates, NH4-phyllosilicates and Mg/Ca-carbonates.The spectral parameters considered in this work are: spectral slopes estimated between 1.2 µm and 1.9 µm, band depths at 2.7-, 3.1-, 3.4- and 4.0-µm, and band centers near 4.0-µm. The ccps spectral parameters were analyzed in conjunction with other Cerean parameters, such as the estimated depth of excavation of the material composing the central peak, in order to search for correlations and information about Ceres’ subsurface.Central peak material located polewards show stronger 2.7- and 3.1-µm band depths with respect to those at the equatorial region, suggesting that subsurface deposits closer to poles are probably richer in Mg- and NH4-phyllosilicates. The 3.4-µm spectral feature is also deeper in ccps located at poleward latitudes, similar to the phyllosilicates. Conversely, the 4.0-µm band does not show this trend with latitude.An increase in both 3.1- and 3.4-µm band depths with the estimated depth of excavation indicates that the spectral feature at 3.4-µm is the result of different contributions from carbonates and NH4-phyllosilicates, as expected. However, depending on their relative influence, the shape of the 3.4-µm spectral feature can vary.Phyllosilicates and carbonates are the resulting products of aqueous alteration of chondritic material and, given the increasing abundance of such minerals (in particular ammoniated phyllosilicates) with depth of excavation, it is likely that our investigation involved subsurface layers nearby the boundary between the volatile-rich crust and the silicate-rich mantle.Na-carbonate is found in the crater central peak material of Ernutet, Haulani and Ikapati, characterized by an estimated depth of excavation of about 6–9 km, where deposits of sodium carbonates could be locally present.

Dormant landslides distributed in upper course of Sun Kosi Watershed and landslides induced by Nepal Gorkha Earthquake 2015

This study detected 897 dormant landslides of deep-seated type in the upper course of the Sun Kosi Watershed. It also shows geology and slope gradient that are prone to cause deep-seated landslides in the Great Himalaya and Midland zones. The dormant landslides are predominantly distributed in geological areas of the Augen Gneiss, Benighat Slate, Robang Phyllite and the Kuncha Phyllite, considering both landslide area ratio and site number. Landslides of deep-seated type are also found prone to develop on dip-slope. Occurrence of landslides usually increases over 20 degrees of slope angle for each geological type, though the number of landslides in the phyllite area increases below 20 degrees. It is very clear that landslides in phyllite area are prone to occur from relatively lower slope angles compared to those occurring in quartzite, gneiss and the Sermathang Formation. Nepal Gorkha Earthquake 2015 caused 1804 landslides in this study area. Most of the earthquake-induced landslides are of shallow types that occurred just below break of slope, showing a shoulder shaped profile along the deep gorge. They are predominantly distributed on steep slopes in the geological areas of slate, gneiss and dolomite. None of the dormant landslides of large scale was activated by the earthquake.

Gallery as rockfall protection measures on roads

AbstractThe risk represents probability for activation of certain geological processes, i.e. processes in geological area provoked from technical activity, including material damages and human victims. The hazard represents probability for activation of certain geological or process in geological area provoked from technical activity, including its intensity and scope. During risk assessment should take into consideration the fact that it is necessary to analyze the potential risks in future. The proper approach for risk management is reducing the risk level, if it's economically and commercial practicable. This paper includes risks assessment and the protection measures on the express road direction A3, section Ohrid – Peshtani and all necessary investigation works performed in order to obtain geotechnical features of the present soil materials and rock formations, essential for the presented analysis.

The landscape-scale relationship between lake sediment geochemistry and catchment bedrock composition from the Temagami and Gowganda areas of Northeastern Ontario, Canada

Lake sediments are integrators of watershed wide environmental information that includes bedrock geology, glacial overburden, vegetation, hydrology and land use. Lake sediments were collected from an area covering approximately 13,600 km2 from the Gowganda and Temagami regions to determine the geochemical background conditions representing different bedrock types. For the entire dataset, the median value for arsenic in lake sediment was 2.6 mg/kg, well within the prescribed limits indicating that the Canadian national objective for arsenic in sediments for the protection of aquatic life (17 mg/kg). Overall, the vast majority of lake sediment samples (97.2%) were below the 17 mg/kg Canadian objective for the protection of aquatic life, however, catchments with Nipissing Diabase had the highest background levels for arsenic (10 mg/kg) with some lakes ranging up to 30 mg/kg. The major geological controls influencing changes in lake sediment geochemistry were determined using random forest classification and principal component analysis (PCA). Random forest classification was able to identify which geological province the samples were derived from and the dominant rock types in the sample catchment with respectable accuracy. PCA revealed strong spatial relationships between lake sediment geochemistry and bedrock geology, particularly a strong relationship between Nipissing Diabase in the watershed of the lake and the cobalt-type mineralization indicator elements in the lake sediment including naturally higher levels of arsenic. Within the samples that exceeded regulatory standards, over half the samples that exceeded the regulatory objectives were located in watersheds that contained Nipissing Diabase in their catchment. This study demonstrates that unique geochemical assemblages can be associated with specific geological areas which is of interest to exploration geologists, for target generation and prospecting, and to environmental policy makers, for site-specific restoration targets.

Dynamic Responses of Bridge–Tunnel Overlapping Structure for High-Speed Railway Under Different Seismic Excitations

There are many bridges and tunnels been built overlapping or close to each other during railway constructions in west or south China recent years. For bridge–tunnel overlapping structures on high-speed railway, serious damage or even complete destruction could be caused when powerful earthquake occurred in complex topography or poor geological areas. However, there is still little research yet on this kind of complex system taking interactions of bridge–tunnel–rock into account, especially for seismic damage or dynamic response mechanism. For purposes of dynamic response analysis and reasonable anti-seismic measures for complex bridge–tunnel overlapping structures, large scale shaking table model tests have been carried out. In shaking table model test, EL-Centro wave (EL) and the Wenchuan wave (WC) were adopted as loading wave in X, Y, Z-direction (perpendicular to the tunnel axis, horizontal along the tunnel axis, and vertical). Test results demonstrated significant differences existing on dynamic responses or variation laws especially in different seismic excitation cases, and fateful consequences could be caused. It also indicated that several sensitive and fragile parts (e.g., the arch vault and arch foot at enlarged section of the tunnel, at the end of the beam and the top of the abutment inside the tunnel portal, and the soil above the tunnel roof etc.) should be strengthened or required special treatment for structural security or overall stability. Simultaneously, seismic excitation combination analysis is important for such overlapping structures in weak surrounding rocks or soils. And the influence caused by the tunnel longitudinal direction should not be ignored for seismic response analysis for such structures. Bidirectional or multi-directional seismic excitation method is proposed for the rationality and accuracy on seismic tests or anti-seismic analysis for same or similar structures.