Coalbed methane is always a major hidden danger that affects mining safety in coal mines. In the study of coal seam water injection to control gas disaster, the increase of free water content is helpful to destroy the integrity of coal seam and to promote the flow of gas in fractures. However, when the free water fills the fracture space, it will increase the flow resistance of gas, and then will reduce

The Kuh-e-Shah complex includes the Paleogene volcano-plutonic belt of the Lut Block, eastern Iran. The volcanic rocks which outcropped in this complex mainly consist of trachy-andesites, andesites, and basaltic-andesites that mineralogically contain plagioclase, pyroxene, hornblende, and minor biotite and olivine. Geochemically, they have features typical of high-K calc-alkaline to shoshsonitic magmas

Interactions between microorganisms and clay minerals influence the transport and cycling of metal contaminants in both marine and terrestrial environments. The present study was conducted to quantify the adsorption of dissolved cadmium, Cd(II), under seawater-like conditions to the marine cyanobacterium Synechococcus sp. PCC 7002, three common clay minerals (kaolinite, montmorillonite and illite)

Recent geodynamic models and geothermometers suggest that slabs in intermediate to hot subduction zone cross the water-saturated basalt solidus, indicating that hydrous silicate melts are important agents of mass transfer from slab to mantle wedge beneath arcs. Yet the effects of basaltic crust-derived hydrous melt fluxing on mantle wedge melting are poorly known. Here we present the melting phase

Knowledge of the identity and thermodynamic properties of aqueous molybdenum (Mo) species at elevated temperatures and pressures is important for understanding the extraction of Mo from source rocks and the formation of hydrothermal deposits. Chlorine and sulfur are two major components in crustal fluids. Several studies have investigated Mo speciation and solubility in chloride-bearing hydrothermal

Stick-slip failure, as a possible mechanism for destructive shallow focus earthquakes, often occurs in heterogeneous faults. To investigate the physical processes of stick-slip failure in heterogeneous faults, direct shear tests are performed in the laboratory, combined with the use of multi-channel high-speed dynamic strain acquisition system, on the bimaterial samples. The bimaterial samples consist

This study presents new high precision age and full-vector archaeomagnetic data from a kiln excavated in the Roman archaeological site of Mitreo's house (Mérida, Badajoz, Spain). The age of the kiln was obtained by the stratigraphic method and by the ceramological study of the italic and sigillata pottery found with a very precise age date of 55 ± 15 years AD. Rock-magnetic experiments pointed towards

In this study continuous waveforms are observed at a short-period dense seismic array which consisted of 302 stations in the Weifang segment of the Tanlu fault zone from August to October 2017. A total of 122,302 Rayleigh wave phase velocity dispersion curves at 1.0–7.5 s periods are extracted to infer a high-resolution shear-wave tomography model of the shallow crust under the region. Our model well

Tailings facilities and associated waters often generate major environmental concerns due to the contaminant potential of the solids and the resulting acid mine drainage. The present study is focused on an area with mining tradition in the department of Santander, Cordillera Oriental - Colombia, where the evolution of mine tailings from gold exploitation resulted in acid mine drainage. An integrated

Mine tailings rich in Mn and an adjacent creek at Kanye, southeast Botswana, have been investigated by total decomposition of solids, X-ray diffraction, EMPA techniques, sequential extraction, and water leaching to understand binding and mobility of Mn and other trace elements. The investigation revealed weathering of tailings close to the surface of the tailings and higher concentrations of Fe compared

Kwanza basin, located on the west coast of Africa and the east side of the South Atlantic Ocean, has the potential for deep-water oil and gas exploration. Previous studies have shown that the pre-salt system within the area has high potential for oil and gas storage. However, due to the shielding effect of the evaporating salt rock during the Aptian period, the quality of seismic reflection profiles

Modern visualization can be formulated as inversion problems that aim to obtain structural information about a complex medium through wave excitations. However, without numerically efficient forward calculations, even state-of-the-art inversion procedures are too computationally intensive to implement. We adapt a method previously used to treat transport in electronic waveguides to describe acoustic

This version of doi:10.1088/1742-2140/aabc74 is being retracted. It was the Publisher's intention to replace the original article with a corrected version following the procedure outlined in 10.1093/jge/gxz118. Due to a production error, however, the corrected version was instead published as a new article 10.1093/jge/aabc74. The Publisher apologises for this mistake.

This version of doi:10.1088/1742-2132/13/5/704 is being retracted. It was the Publisher's intention to replace the original article with a corrected version following the procedure outlined in 10.1093/jge/gxz113. Due to a production error, however, the corrected version was instead published as a new article 10.1093/jge/704. The Publisher apologises for this mistake.

This version of doi:10.1088/1742-2140/aa6b28 is being retracted. It was the Publisher's intention to replace the original article with a corrected version following the procedure outlined in 10.1093/jge/gxz114. Due to a production error, however, the corrected version was instead published as a new article 10.1093/jge/aa6b28. The Publisher apologises for this mistake.

This version of doi:10.1088/1742-2140/aa953a is being retracted. It was the Publisher's intention to replace the original article with a corrected version following the procedure outlined in 10.1093/jge/gxz115. Due to a production error, however, the corrected version was instead published as a new article 10.1093/jge/aa953a. The Publisher apologises for this mistake.

This version of doi:10.1088/1742-2140/aaaf57 is being retracted. It was the Publisher's intention to replace the original article with a corrected version following the procedure outlined in 10.1093/jge/gxz117. Due to a production error, however, the corrected version was instead published as a new article 10.1093/jge/aaaf57. The Publisher apologises for this mistake.

This version of doi:10.1088/1742-2140/aaa981 is being retracted. It was the Publisher's intention to replace the original article with a corrected version following the procedure outlined in 10.1093/jge/gxz116. Due to a production error, however, the corrected version was instead published as a new article 10.1093/jge/aaa981. The Publisher apologises for this mistake.

A shot-encoding technique can be used in seismic waveform inversion to significantly reduce the computational cost by reducing the number of seismic simulations in the inversion procedure. Here we developed two alternative shot-encoding schemes to perform simultaneous-sources waveform inversion. The first scheme (I) encodes shot gathers with random-phase rotations applied to seismic traces. The second

The reverse time migration of an elastic wave is an advanced method for an imaging velocity model, and the reverse time migration of an elastic inhomogeneous TTI medium has become a research hotspot. The amount of calculation and storage is an important factor restricting its development. To solve the storage problem, we improve the wave field separation algorithm using adaptive sampling in the process

Foothill belts ‘dual-complexity’ of the surface and underground structures hinders an accurate seismic imaging of complex geological structures. In this paper, the propagation law of the seismic wavefield in the foothill belt is studied through seismic forward modelling and its influences on the seismic data acquisition and imaging. A foothill belt with typical ‘dual-complexity’ characteristics is

In vertical seismic profiling (VSP) exploration, it is difficult to produce an accurate image for large-offset reflections only using reflection waves and the image resolution is low in traditional VSP-CDP stacking as is the number of folds of reflection points. To mitigate these problems, we present an inverse Gaussian beam stacking method for imaging both primary reflections and free-surface multiples

Geological disposal is a feasible and safe method for dealing with the high-level radioactive waste problem at present. The Beishan area is the key area preselected for high-level radioactive waste geological disposal in Gansu Province, China. The Jijicao rock block is currently the most extensively studied area, where there are several fracture zones in borehole BS15. In 2011, a remarkable conductive

We apply the single-station microtremor horizontal-to-vertical spectral ratio (HVSR) method to image the geometry of Pohang Basin, South Korea, which experienced the greatest earthquake damage in Korea during a series of anthropogenic earthquakes between November 2017 and February 2018. We collected and analysed the ambient seismic noise at 124 temporary stations. The resonance frequencies, which vary

Rifting in the Afar region is considered to be the only known example of the formation of an incipient divergent triple junction. Taking the Afar region as an example, we use three‐dimensional lithospheric‐scale laboratory experiments to constrain the factors controlling the structure and the tectonic evolution of the area. We systematically evaluate the role of different pre‐existing heterogeneities

Evaporites play a major role in the evolution of an orogenic wedge, modifying the shape and the deformation kinematics inside the wedge. Salt tectonics can occur at various stages, but early salt activity can create a structural inheritance which compartmentalizes the building of the sedimentary succession and the mechanical architecture of the orogenic wedge. Sub‐Alpine fold‐and‐thrust belts commonly

Impact craters are the dominant features on the Moon, and their degradation with time is the most common geological process on this body. This work is aimed at detailed quantitative characterization of this process. We quantitatively characterize crater materials by (1) the topographic roughness calculated from Lunar Orbiter Laser Altimeter and (2) rock abundances and nighttime soil temperatures derived

The phase and group velocity surfaces are essential for wave propagation in anisotropic media. These surfaces have certain features that, especially, for shear waves result in complications for modelling and inversion of recorded wavefields. To analyse wave propagation in an anisotropic model, it is important to identify these features in both the phase and group domains. We propose few characteristics

Locating passive-source positions by using microseismic events is essential for monitoring hydraulic fractures. Among all microseismic source locating approaches, time-reversal imaging (TRI) is a promising one that is based on the principle that all of the back-propagated receiver wavefields should coincide at the source position when the velocity is accurate. It can image microseismic sources by applying

The corrosion problem of a production system has been affecting the normal operation of an in situ combustion project. Because the environment of production system is significantly different in tubing, gas, liquid, and temperature in in situ combustion, the problem of the corrosion should be treated differently according to its origin. Based on the main environment of gas-liquid of the production system

Capillary pressure curve data measured through the mercury injection method can accurately reflect the pore throat characteristics of reservoir rock; in this study, a new methodology is proposed to solve the aforementioned problem by virtue of the support vector regression tool and two improved models according to Swanson and capillary parachor parameters. Based on previous research data on the mercury

The 1.26 Ma Tshirege Member of the Bandelier Tuff is the second of two major (~ 400 km3, dense rock equivalent) compositionally zoned rhyolitic eruptions from the Valles caldera. Here we analyze 25 samples of a minor component of compositionally and texturally variable silicic dacite pumice (~ 67 to 72% SiO2) that is widely distributed through the unit. The dacite has a phenocryst assemblage dominated

The high-pressure behavior of manganese diselenide MnSe2 was investigated by synchrotron angle-dispersive X-ray diffraction (ADXRD) and infrared reflection spectroscopy equipped with a diamond-anvil cell. It was found that MnSe2 with a pyrite-type structure undergoes a transformation into a disordered intermediate phase at ~ 12.5 GPa, with a ground state composed of an arsenopyrite-type structure,

Volatility determines the gas-particle partitioning of organic compounds. Volatility is thus a key property needed to understand the behavior of organic aerosol (OA) in the atmosphere. Various studies have been conducted to experimentally measure and numerically simulate distributions of OA volatility. The observed OA evaporation rates have generally been slower than the rates assuming instantaneous

Unconventional mineral dust, such as fly ash, road dust and industrial dust, could contribute significantly to fine particulate matters; however, their hygroscopicity remains largely unexplored. In this work, a vapor sorption analyzer and a diffusion reflectance infrared Fourier transform spectroscopy (DRIFTS) were used to examine hygroscopic properties of eleven unconventional mineral dust samples

We consider propagation of surface Transverse Electric (TE) waves in a rod filled with nonlinear metamaterial medium. The problem is reduced to the analysis of a nonlinear integral equation with a kernel in the form of the Green function of an auxiliary boundary value problem on an interval. The existence of propagating nonlinear surface TE waves for the chosen nonlinearity (Kerr law) is proved using

Clinopyroxene is a common phase in a variety of hydrothermal ore deposits, notably in skarn deposits where it typically occurs as a major constituent. It commonly displays variations in texture and composition due to changing physicochemical conditions and contains relatively high concentrations of rare earth elements (REEs), making it an important petrogenetic indicator. In this study, we integrate

A small-scale hydrothermal uranium mineralization hosted within the siderite deposit at Hüttenberg (Eastern Alps, Austria) was re-investigated using modern scanning electron microscope (SEM) and microprobe (EMPA) methods. The uranium mineralization comprises brannerite, coffinite and uraninite, and is spatially associated with Fe-, Ni- and Co-arsenides (loellingite, rammelsbergite, safflorite), bismuth

Since the Apollo 14 mission delivered samples of the Fra Mauro formation, interpreted as ejecta of the Imbrium impact, defining the age of this impact has emerged as one of the critical tasks required for the complete understanding of the asteroid bombardment history of the Moon and, by extension, the inner Solar System. Significant effort dedicated to this task has resulted in a substantial set of

Many microorganisms including free-living and symbiotic fungi weather minerals through the formation of biofilms on their surface. Weathering thus proceeds not only according to the mineral's chemistry and the environmental conditions but also according to the local biofilm chemistry. These processes can be dissected in experiments with defined environmental settings and by employing genetic tools

It has been proposed that magnetic flux expulsion due to outer core fluid upwellings may affect the geomagnetic secular variation on the core-mantle boundary (Bloxham 1986). In this process intense horizontal field lines are concentrated below the outer boundary, introducing small radial length scales and consequently strong radial diffusion. Here we explore such magnetic boundary layers in numerical

Concern has been raised about the potential formation of acid sulfate soils and associated environmental problems related to peat extraction and, thus, peat, sediment and till characteristics of 15 well drained peat extraction fields were investigated in northern and northwestern Finland. The aim was to identify and characterize the occurrence/abundance of potential acid (hypersulfidic) and actual

Based on SEMUCB‐WM1 tomographic model, validated by other recent models, and fluid mechanics constraints, we show that the large low shear velocity provinces (LLSVPs) present at the base of the Earth's mantle beneath the Pacific and Africa do not extend as compact, uniform structures very high above the core‐mantle boundary. In contrast, they contain a number of well‐separated, low‐velocity conduits

Fifteen natural gas samples were collected from the autochthonous Miocene strata between Dębica and Przemyśl towns in the eastern sector of the Polish Carpathian Foredeep. The samples were analysed for the molecular and stable isotope compositions of carbon (δ13C in CH4, C2H6, C3H8, i-C4H10, n-C4H10 and CO2), hydrogen (δ2H in CH4, C2H6 and C3H8), nitrogen (δ15N in N2), and all stable isotopes of noble

Yanshanian magmatism develops well and has obvious metallogenic specificity in the Qinzhou–Hangzhou bays of South China. Zircon, in granite, has great potential in the study of metallogenic specificity. Moreover, with the development of in-situ zircon analysis technology, a significant amount of data on zircon composition has become available in recent years. Hence, to further elucidate the distinctive

This research focused on the concentrations, pollution assessment, and source identification of eight heavy metals in acidic farmland of the karst region in China. Two hundred eighty-eight soil samples (0–20 cm) were collected from farmland in the karst region of Quanzhou County, Guangxi Province and analysed using multiple methods. The results revealed that the average concentrations of Cd, Pb, Zn

Brittle deformation in rocks depends upon loading rate; with increasing rates, typically greater than ~102 s‐1, rocks become significantly stronger and undergo increasingly severe fragmentation. Dynamic conditions required for rate‐dependent brittle failure may be reached during impact events, seismogenic rupture, and landslides. Material characteristics and fragment characterization of specific geomaterials

Since landing in late 2018, the InSight lander has been recording seismic signals on the surface of Mars. Despite nominal pre‐landing estimates of 1‐‐3 meteorite impacts detected per Earth year, none have yet been identified seismically. To inform revised detectability estimates, we simulated numerically a suite of small impacts onto Martian regolith and characterized their seismic source properties

The estimation of time‐lapse time shifts between two, or several, repeated seismic surveys has become increasingly popular over the past eighteen years. These time shifts are a reliable and informative seismic attribute that can relate to reservoir production. Correction for these time shifts or the underlying velocity perturbations and/or subsurface displacement in an imaging sense also permits accurate

The increasing rate and magnitude of induced seismicity over the past decade has generated public interest and spurred research across a broad range of geoscientists and stakeholders. Here, induced seismicity is broadly defined to include earthquakes associated with geothermal exploration, hydrocarbon production, wastewater disposal, carbon sequestration, and gas storage. Innovations in energy technologies

The clustering behavior of injection‐induced earthquakes is examined using one month of data recorded by the LArge‐n Seismic Survey in Oklahoma (LASSO) array. The 1829‐node seismic array was deployed in a 25 km×32 km area of active saltwater disposal in northern Oklahoma between 14 April and 10 May 2016. Injection rates in the study area are nearly constant around the time of the deployment. We develop

The development of organic‐rich, low‐permeability formations for hydrocarbon production requires the use of unconventional techniques such as multiwell pad drilling of horizontal wells and massive multistage hydraulic‐fracturing stimulations. However, proliferation of these unconventional development methods has been linked to localized cases of fault reactivation during or shortly after hydraulic

The sequence of foreshocks, mainshock, and aftershocks associated with a fault rupture is the result of interactions of complex fault systems, the tectonic stress field, and fluid movement. Analysis of shock sequences can aid our understanding of the spatial distribution and magnitude of these factors, as well as provide seismic hazard assessment. The 2017 Mw 5.5 Pohang earthquake sequence occurred

Two M 5 earthquakes struck the southeastern Korean Peninsula in September 2016 and November 2017, causing damage near the epicentral areas. We analyze the stress‐drop scaling of these two earthquake sequences using coda‐based methods and Bayesian inversion. The 2016 Gyeongju earthquake sequence is a typical earthquake sequence generated by tectonic processes. In contrast, the 2017 Pohang earthquake

A generalized inversion technique (GIT) is applied to local seismic data from 90 induced earthquakes (⁠ML 2.0–3.9) in the Fort Worth Basin (FWB) of north Texas to separate path, site, and source characteristics and to improve local seismic hazard assessment. Seismograms from three earthquake sequences on spatially separated basement faults are recorded on 66 temporary stations. Because of the lack