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

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

We investigated the electrical conductivity of Ti‐H doped synthetic olivine aggregates at 4 GPa, 873–1273 K and controlled oxygen fugacities. Under a given pressure and temperature, electrical conductivity depends both on hydrogen and Ti content, but these samples show different conductivity behavior from that observed in Ti‐poor sample such as San Carlos olivine. We found that when Ti content is comparable

Southwest Japan is an island arc formed by subduction of the Philippine Sea (PHS) plate. The Quaternary magmatism in this region is characterized by eruptions of high‐Sr andesites and dacites, considered to have been derived by melting of the PHS plate. The loci of these volcanoes spatially coincide with seismic discontinuities of the subducted PHS plate. Thus the magmatism is interpreted as the result

To assess the risk of tsunamis from outer‐rise earthquakes, we carried out tsunami simulations using 33 simple rectangular fault models with 60° dip angles based on marine seismic observations and surveys of the Japan Trench. The largest tsunami resulting from these models, produced by a Mw 8.7 normal‐faulting event on a fault 332 km long, had a maximum height of 27.0 m. We tested variations of the

Thermal pressure is an inevitable thermodynamic consequence of heating a volumetrically constrained sample in the diamond anvil cell. Its possible influences on experimentally determined density‐mineralogy correlations are widely appreciated, yet the effect itself has never been experimentally measured. We present here the first quantitative measurements of the spatial distribution of thermal pressure

We investigated temporal variations of seismic wave velocity associated with hydraulic fracturing using Green's functions computed from ambient noise data. In October and November of 2014, we set up a broadband array at a shale play site inside the Sichuan basin where a pilot horizontal drilling and hydraulic injections were conducted. We first computed cross‐correlation functions using continuous

Wood dynamics affects riparian ecosystem functioning and river morphology. The spatial and temporal dynamics of wood pieces in river corridors, in particular of deposited rejuvenated wood logs, depend on their biomechanical properties and resistance to uprooting. The ability of stranded wood logs to withstand drag forces depends on how efficiently their roots have sprouted and on the interarrival time

One of the primary challenges associated with evaluating smoke models is the availability of observations. The limited density of traditional air quality monitoring networks makes evaluating wildfire smoke transport challenging, particularly over regions where smoke plumes exhibit significant spatiotemporal variability. In this study, we analyzed smoke dispersion for the 2018 Pole Creek and Bald Mountain

The East Asian westerly jet (EAWJ) features large seasonal variations in its intensity and position and exerts profound influences on local precipitation. In this study, we found the amplified seasonality of the EAWJ in response to the mid‐Holocene forcing. Compared with the preindustrial, the summer EAWJ significantly weakens by 20 ± 4% and shifts northward by 4 ± 2° during the mid‐Holocene, while

The samples of atmospheric total suspended particle (TSP) were obtained at the remote Tibetan site (named Lulang) from November 2015 to November 2016. The seasonal characteristics of n‐alkanes, polycyclic aromatic hydrocarbons (PAHs) variations, and their correlations to brown carbon (BrC) light absorption in TSP were investigated. Elevated TSP n‐alkanes and PAHs levels were observed in winter (2.8

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

The present study investigates long-term variation in aerosol optical properties (AOP) and their associated climatic implications over selected cities of Chitral, Gwadar, Karachi, Lahore, Peshawar and Quetta in Pakistan for the period 2005–2018. For this purpose, aerosol optical depth (AOD) and aerosol index (AI) are retrieved from Moderate Resolution Imaging Spectroradiometer (MODIS) and Ozone Monitoring

We perform a superposed epoch analysis on two groups of selected geospace disturbance events, emerging from single and isolated interplanetary drivers, and resulting in either the enhancement or the depletion of the average relativistic electron Phase Space Density (PSD). We investigate the occurrence of behavioural/temporal patterns of solar wind and geomagnetic parameters, chorus and ULF Pc5 wave

An attempt has been made to understand the effect of the cirrus clouds on the tropical tropopause thermal structure over a tropical station Gadanki (13.45oN, 79.2oE) using regular radiosonde observation at 12:00Z and CALIPSO measurements at the closest proximity to Gadanki during 2006–2013. As the CALIPSO and radiosonde observation timings are not simultaneous, we considered only those cases when cirrus

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 concrete-filled FRP (Fiber-reinforced Polymer)-steel composite tube (CFCT) column is a new structure that integrates the advantages of various materials. The establishment of the cyclic stress-strain relationship under axial loading is of great importance for the seismic analysis and design method of this new structure. In this study, the stress-strain behaviors of six CFCT columns with various

A rheological constitutive model for damaged zone evolution of a tunnel is proposed in this paper to describe the strain hardening and softening properties of the excavation-disturbed rock mass. Firstly, the one-dimension rheological model is introduced by connecting the improved St. Venant body with the Nishihara model, and this model can be used to describe the whole process including transient viscoplastic

With the development of carbon dioxide sequestration, the influence of carbon dioxide on coal properties has been paid more and more attention by experts and scholars. Scanning electron microscopy was employed to observe the three-point bending characteristics of bituminous coals treated with or without carbon dioxide gas. The experimental results showed that the carbon dioxide gas treatment had obvious

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

A limited gap between closely spaced structural parts may induce internal pounding in seismically isolated structures, because of notable displacement at the level of the isolation system under severe earthquakes. A gap between a fixed-base elevator shaft and the surrounding building is presented here with reference to a reinforced concrete building located in the Sicilian town of Augusta. The building

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,

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

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

In this study, we evaluated the variations of air quality in Lanzhou, a typical city in Northwestern China impacted by the COVID‐19 lockdown. The mass concentration and chemical composition of non‐refractory submicron particulate matter (NR‐PM1) were determined by a high‐resolution aerosol mass spectrometer from January to March 2020. The concentration of NR‐PM1 dropped by 50% from pre‐ to during control

No abstract is available for this article.

Earthquake source parameters such as slip distribution and slip rate are useful information for understanding the physical processes behind earthquakes. The isochrone back-projection method, or isochrone-BPM, is one of the methods used to obtain slip distribution in the fault plane by incorporating the isochrone concept with back-projection method. Isochrone-BPM has advantages in its ease of implementation

The present study investigates the annual displacement of ITCZ and its role in forming and strengthening the precipitation systems in the southern part of Iran. To this end, the daily precipitation data of 71 meteorological stations were received. Then, the precipitation systems throughout cold seasons (October to May) were extracted. Next, the systems with maximum precipitation average were selected

Earth’s surface topography/bathymetry and gravity fields provide important constraints on crustal structure and the tectonic processes that act on it due, for example, to plate flexure and mantle convection. Such studies require, however, high accuracy measurements at a wide range of spatial scales. During the past few decades much progress has been made in the acquisition of bathymetry and gravity

In regions with small ocean plates and continental blocks, such as the Mediterranean in the Cenozoic and modern Indonesia, many blueschists may be stored at shallow depth in mantle lithosphere that is newly formed during the amalgamation of small continental blocks and oceans. Melting of these blueschists at low pressures in mixed lithosphere of this type during post‐collisional relaxation may be involved

The Changjiang Estuary and adjacent sea area in the East China Sea suffer from frequent harmful algal blooms. However, the relative importance of riverine nutrient input from the Changjiang River and oceanic nutrient input from the Taiwan Warm Current and Kuroshio Current to the development and distribution of summer phytoplankton blooms in this area remains unclear. To address this problem, we deployed

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

Stratospheric water vapor (SWV) changes, in response to increasing CO2, as a feedback component may play an important role in the Earth's energy budget. It has drawn extensive studies in the past decade. Here, we calculate the SWV climate feedback using the 150‐year CO2 forcing (1pctCO2) simulations in the CMIP6 ensemble of models. All models robustly show a moistening of the stratosphere, causing

The Himalayas and Tibetan Plateau, identified as the Third Pole (TP), is a unique region because of its insertion into global environmental and climatic changes. Deposition of atmospheric nitrate in this region is one of the most important sources of reactive nitrogen to glacial‐hydrologic system and ecosystems. The isotopic composition of atmospherically deposited nitrate preserved in ice bodies plays

The majority of the aerosol particle number (condensation nuclei or CN) in the marine boundary layer (MBL) consists of sulfate and organic compounds that have been shown to provide a large fraction of the cloud condensation nuclei (CCN). Here we use submicron non‐refractory Aerosol Mass Spectrometer (AMS) and filter measurements of organic and sulfate components of aerosol particles measured during

This paper presents the performance of geofoam-filled trenches in mitigating of ground vibration transmissions by the means of a full experimental study. The results are interpreted in the frequency domain. Fully automated 2D and 3D numerical models are applied to evaluate the screening effectiveness of geofoam-filled trenches in the active and passive schemes. Experimental results are in good agreement

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