A new method to remove hydrogen sulfide from geothermal fluids during well operation was tested in situ at a geothermal site in Vienna (Austria). For this purpose, ferric iron was added either as granulated iron hydroxide or as FeCl3 solution into a reaction vessel containing the thermal water directly removed from the wells. From the container, the water would be pumped through a particle filter.

A thick Infra-Cambrian to Phanerozoic sedimentary sequence in eastern Arabia conceals a poorly known Neoproterozoic basement that once separated the currently exposed Arabian Shield (western Arabia) from NW India in Gondwana. In this study, the Arabian Platform (eastern Arabia) is targeted by relatively high-resolution passive-source seismic tomography for the first time, which aims to illuminate crust

Between February 6 and 12, 2016, an earthquake sequence affected the western sector of the Hyblean foreland domain in SE Sicily (Italy), a region characterized by several disastrous events, as the seismic history describes, of which little is still known about the seismogenic sources. Despite the low magnitude of most events (MLmax 4.3), the sequence represents one of the largest episodes of seismic

Among the mechanisms of the mass transport within the Earth's crust and the upper mantle the magma movement within the dykes is very important. In some dykes, the magma movement is represented by almost free flow infilling more or less open fractures in the host rocks, while it has character of forceful injection of the host rocks in the other dykes. The magnetic fabric originated by the free flow

Carbonaceous mortars from Novae (Bulgaria) contain local loess, crushed bricks and ceramic dust (pozzolanic materials). The reaction between lime and pozzolanic additives occurs easily and affects the rate and course of leaching reaction of carbonates in orthophosphoric acid during the sample pretreatment for dating. The composition of the Bulgarian mortars does not allow for unambiguous conclusions

Connecting calendar ages to radiocarbon (14C) ages, i.e. constructing a calibration curve, requires 14C samples that represent, or are closely connected to, atmospheric 14C values and that can also be independently dated. In addition to these data, there is information that can serve as independent tests of the calibration curve. For example, information from ice core radionuclide data cannot be directly

To study the evolution law of the discharge pathway for the old goaf water in the Datong mining area, a new fluid-solid coupling similar material was developed based on the fluid-solid coupling similarity theory. In the developed similar material, sand and barite powder were used as aggregate, polyurethane and white portland cement as binder, and water and silicone oil as regulator. The effects of

Fluid flow in the subsurface is fundamental in a variety of geological processes including volcanism, metamorphism, and mineral dissolution and precipitation. It is also of economic and societal significance given its relevance, for example, within groundwater and contaminant transport, hydrocarbon migration, and precipitation of ore-forming minerals. In this example-based overview, we use the distribution

Squirt driven by local pressure imbalance between contact of grains (or throat) and the main pore space is a mechanism of P-wave attenuation in consolidated rocks. In this paper, we investigate squirt in unconsolidated and consolidated porous media (represented by Toyoura sands and compressed glass beads, respectively). The former sample has very small bulk modulus and shear modulus, manifested by

Geothermal fields are prone to temperature fluctuations from natural hydrothermal activity, anthropogenic drilling practices, and magmatic intrusions. These fluctuations may elicit a response from the rocks in terms of their mineralogical, physical (i.e., porosity and permeability), and mechanical properties. Hyaloclastites are a highly variable volcaniclastic rock predominantly formed of glass clasts

Thirty years ago, Rob Van der Voo proposed an elegant and simple system for evaluating the quality of paleomagnetic data. As a second-year Ph.D. student, the lead author remembers Rob waxing philosophical about the need to have an appropriate, but not overly rigid evaluation system. The end result was a 7-point system that assigned a (1) or (0) for any paleomagnetic result based on objective criteria

In every tight formation reservoir, natural fractures play an important role for mass and energy transport and stress distribution. Enhanced Geothermal Systems (EGS) make no exception, and stimulation aims at increasing the reservoir permeability to enhance fluid circulation and heat transport. EGS development relies upon the complex task of predicting accurate hydraulic fracture propagation pathway

Near‐field observations of tsunami waves generated by the M w9.2 1964 Alaska earthquake reveal a complex relationship between coseismic slip and the tsunami wavefield in the source area. The documented times and amplitudes of first arrivals, measured run‐up heights and inundation areas along the coasts of the Kenai Peninsula and Kodiak Island show that secondary splay faults played an important role

We investigate theoretical limits to detection of fast and slow seismic events, and spatial variations of ground motion expected from M 6 earthquakes at short epicentral distances. The analyses are based on synthetic velocity seismograms calculated with the discrete wavenumber method assuming seismic velocities and attenuation properties of the crust in Southern California. The examined source properties

Microbursts are meteorological phenomena in the lower troposphere which can produce damaging surface winds and pose a severe risk to aircraft flying close to the ground. As these events usually span less than 4 km and 15 min, the spatiotemporal resolution is a challenge for numerical simulations. Although research of microburst using operative mesoscale models is scarce, the Weather Research and Forecasting

Wave‐induced pore‐fluid flows (WIFF) are recognized as an important cause of seismic‐wave attenuation at frequencies below 1 kHz within heterogeneous rock. By using Lagrangian continuum mechanics, WIFF mechanisms can be classified strictly on the basis of macroscopic non‐Biot's material properties. In this classification, types I and II WIFF are identified by local internal deformations being elastically

Impedance is a physical parameter that plays an important role in seismic data processing and interpretation. A relative impedance perturbation (the ratio of the impedance perturbation and the impedance for the background models) imaging method in depth domain based on the reflection wave equation is proposed. Under the small perturbation assumption, primary wave and high‐frequency approximation condition

Inversion of magnetic data is complicated by the presence of remanent magnetization, and it provides limited information about the magnetic source because of the insufficiency of data and constraint information. We propose a Fourier domain transformation allowing the separation of magnetic anomalies into the components caused by induced and remanent magnetizations. The approach is based on the hypothesis

Bridges tend to sustain excessive seismic demand (e.g. displacement) under pulse-like ground motions attributing to the effect of forward directivity, which is of high likely to occur at locations near the fault rupture. This study tries to incorporate the pulse effect into the probabilistic seismic hazard analysis (PSHA) and probabilistic seismic demand analysis (PSDA) framework, which are combined

The main objective of this study is to investigate the effect of spectral shape on damping modification factors η used in equivalent static and response spectrum analyses of structures with damping ratios that are different from 5% critical damping. Record-to-record variability of η is also evaluated through a statistical analysis of 5270 ground motions records from 1137 interface earthquakes recorded

Viscoelastic behaviour of materials at the lithosphere-asthenosphere boundary is observed in this paper. The observed post-seismic and aseismic deformation help us to understand the rheological properties of the mantle and asthenosphere. A quasi-static model having homogeneous, isotropic, elastic material overlying viscoelastic material of a standard linear solid (SLS) is considered. A long strike-slip

A numerical technique for detecting the number and shape of subsurface cavities is presented, applying the particle filter and the parametric level set method to elastic wave propagation under the ground. When subsurface cavities exist, the elastic wave propagating in the ground is reflected at the boundary faces of the cavities. Observing the velocity of the reflection wave at the surface of a ground

This study focuses in the analysis of the internal structure of the upper 3 km of Los Humeros caldera and the relation of electrical and hydrothermal anomalies. For this purpose, we measured, processed, and interpreted 78 broadband magnetotelluric (MT) soundings. We performed a 3D inversion of the data set (ModEM) using all MT soundings, although only half of the available frequencies per sounding

Most prior studies on decoupling of a stratocumulus‐topped boundary layer (STBL) are focused on subtropics where cold air advection with moderate strength is dominant. This study expands across a wider spectrum of temperature advection spanning from moderately strong warm air advection to extremely strong cold air advection. A STBL undergoing warm advection is found to be more mixed than a STBL undergoing

Determining the spatial relations between volcanic edifices and their underlying magma storage zones is fundamental for characterizing long‐term evolution and short‐term unrest. We compile centroid locations of upper crustal magma reservoirs at 56 arc volcanoes inferred from seismic, magnetotelluric, and geodetic studies. We show that magma reservoirs are often horizontally offset from their associated

Turbulence parameters have been estimated from microstructure velocity and temperature measurements in an anticyclonic Loop Current Eddy in the Gulf of Mexico for the very first time. Measurements were performed during a mission in October 2016, using a G2 Webb Research Slocum ocean glider instrumented with a microstructure sensors suite. Well‐defined turbulent kinetic energy dissipation rate patterns

The Kelvin‐Helmholtz Instability (KHI) is thought to be an important driver of mass and momentum transfer from the solar wind to the Earth's magnetosphere. We present observations from NASA's Magnetospheric Multiscale mission of ion acoustic‐like waves associated with turbulence during the KHI interval on 8 September 2015. These parallel electrostatic waves are nonlinear, can have amplitudes in excess

We test the hypothesis that ocean seafloor pressures impart stresses that alter the initiation or termination of transient slow slip events (SSEs) on shallow submarine and near‐coastal faults, using simulated seafloor pressures and a new catalog of SSEs in the Hikurangi subduction zone. We show that seafloor pressures may be represented by an average time history over the ~100‐km dimensions of the

Earthquake early warning would be improved if the final size of an ongoing earthquake could be predicted early in the rupture process. Previous research relies largely on parameters derived from seismic waveforms, resulting in widely varied estimates of how much of the rupture must be complete before final sizes can be predicted. We demonstrate here that incorporating prior information on along‐strike

Seismicity in the Raton Basin over the past two decades suggests reactivation of basement faults due to waste‐water injection. In the summer of 2018, 96 short period three‐component nodal instruments were installed in a highly active region of the basin for a month. A machine‐learning based phase picker (PhaseNet) was adopted and identified millions of picks, which were associated into events using

Extreme and persistent haze events frequently occur during wintertime China. While recent emissions reductions reduced annual mean fine particulate matter (PM2.5) concentrations over eastern China, their effectiveness on wintertime PM2.5 trend remains uncertain. We use observations and model simulations to quantify seasonal differences in PM2.5 trends and investigate the underlying chemical mechanisms

The Longmendian Ag–Pb–Zn deposit is located in the southern margin of the North China Craton, and the mineralization occurs mainly in quartz veins, altered gneissic wallrocks, and minor fault breccias in the Taihua Group. Based on vein crosscutting relations, mineral assemblages, and paragenesis, the mineralization can be divided into three stages: (1) quartz–pyrite, (2) quartz–polymetallic sulfides

Fewer than 200 radiocarbon (14C) dates with secure contextual information are available for Cuba, making it challenging to reconstruct Caribbean indigenous population dynamics, their identities and interactions. In this paper, we discussed 21 accelerator mass spectrometry (AMS) 14C dates from two mounds (M1 and M2) at the Playa del Mango site (Granma province, Cuba), traditionally associated with the

Reversals and plateaus in the radiocarbon (14C) calibration curve lead to similar 14C ages applying to a wide range of calendar dates, creating imprecision, ambiguity, and challenges for archaeological dating. Even with Bayesian chronological modeling, such periods remain a problem when no known order—e.g., a stratigraphic sequence—exists, and especially if site durations are relatively short. Using

Estimating earthquake occurrence rates from the accumulation rate of seismic moment is an established tool of seismic hazard analysis. We propose an alternative, fault‐agnostic approach based on the conservation of energy: the Energy‐Conserving Seismicity Framework (ENCOS). Working in energy space has the advantage that the radiated energy is a better predictor of the damage potential of earthquake

With substantial postglacial rhyolite eruptions and on‐going rapid uplift, the Laguna del Maule volcanic field in the southern Andes provides an exceptional opportunity to study the dynamics of an active silicic magmatic system. Using 4,093 P‐arrivals from 137 distant earthquakes recorded by 44 local stations over ~2.25 years, we conduct teleseismic tomography to image the crustal structure down to

Seismic body‐wave tomography studies typically assume an isotropic upper mantle, possibly mapping anisotropy into artificial isotropic velocity anomalies in the resulting images. The Eastern Mediterranean with its oceanic, continental and extinct subduction systems, as well as dense station coverage, provides an ideal setting to explore this issue. To examine the influence of seismic anisotropy, our

Leaf area index (LAI) is a vegetation structural parameter that modulates the interaction between the land surface and the atmosphere and therefore is used in many terrestrial biosphere models. However, there are still large uncertainties in simulating the global LAI in Earth system models. In this study, we used climate and soil variables and the Farquhar’s biochemical model to reconstruct global

Structure-canyon-structure interaction is investigated using a whole model of two shear walls supported by rigid foundations on both sides of a semi-circle river-canyon embedded in a homogenous half-space. A closed-form analytical solution is presented for the model response to incident plane SH-wave based on the wave function expansion method. The analysis focuses on the effects of the structure-canyon-structure

A hybrid force/displacement (HFD) performance-based seismic design method is proposed for two types of plane reinforced concrete structures, i.e., infilled moment-resisting frames (I-MRFs) and wall-frame dual systems (WFDS). The HFD seismic design method is a force-based method which controls with high accuracy both structural and non-structural deformation limits. The behavior factor is related here

This study introduced a new design of the grouted corrugated duct connection (GCDC), which improves the structure integrity, bond strength and ease of constructability. A two-phase experimental program was performed to fully understand the connection behaviour. Phase I focused on the pull-out tests of 32 specimens in two batches with various conditions. It indicates that a connection length of 30 times

No abstract is available for this article.

Spaceborne radars offer a unique three‐dimensional view of the atmospheric components of the Earth's hydrological cycle. Existing and planned spaceborne radar missions provide cloud and precipitation information over the oceans and land difficult to access in remote areas. A careful look into their measurement capabilities indicates considerable gaps that hinder our ability to detect and probe key

Back analysis can provide engineers with important information for better decision‐making. Over the years, research on back analysis has focused mainly on optimisation techniques, while comparative studies of data‐interpretation methodologies have seldom been reported. This paper examines the use of three data‐interpretation methodologies on the performance of geotechnical back analysis. In general

Rapid development of time-lapse seismic monitoring instrumentations has made it possible to collect dense time-lapse data for tomographically retrieving time-lapse (even continuous) images of subsurface changes. While traditional time-lapse full waveform inversion (TLFWI) algorithms are designed for sparse time-lapse surveys, they lack of effective temporal constraint on time-lapse data, and, more

For the time stationary global geomagnetic field, a new modelling concept is presented. A Bayesian non-parametric approach provides realistic location dependent uncertainty estimates. Modelling related variabilities are dealt with systematically by making little subjective a priori assumptions. Rather than parameterizing the model by Gauss coefficients, a functional analytic approach is applied. The

The composition of the Earth's core and mantle is set by the chemical equilibrium between metals and silicates during core/mantle segregation. The metallic core separated from the mantle by gravitational descent in the form of diapirs in a magma ocean, and therefore the dynamics of the diapir's downward movement has an influence on the chemical equilibrium. In this study, we characterize the descent

The North Alpine Foreland Basin in SE Germany is Germany’s most active deep geothermal province. However, in its southern and eastern part the basin is considerably overpressured, which is a significant challenge for drilling deep geothermal wells. In this study, we combine drilling data and velocity-based pore pressure analyses with 3D basin modeling to assess the predictability and controlling factors

Transport theory is used to calculate the intensity of a wave propagating though a trunk‐dominated forest. The trunks are replaced by parallel infinitely long dielectric cylinders, and a vertically polarized plane wave is normally incident on the layer of these randomly distribution parallel cylinders. The problem can be reduced to a two‐dimensional transport problem that can be solved by the eigenvalue

Hyaloclastites commonly form high-quality reservoir rocks in volcanic geothermal provinces. Here, we investigated the effects of confinement due to burial following prolonged accumulation of eruptive products on the physical and mechanical evolution of surficial and subsurface (depths of 70 m, 556 m, and 732 m) hyaloclastites from Krafla volcano, Iceland. Upon loading in a hydrostatic cell, the porosity

Deep geothermal resources are becoming an increasingly important energy source worldwide. To achieve the optimal efficiency of this resource, the heat transfer characteristics between flowing water and rock need to be further studied. Using the stereotopometric scanning system 3D CaMega, the fracture geometry data of five cuboid granite rocks were obtained to determine the effects of fracture roughness

We perform coda-wave attenuation for the Western Iberiaand, for the first time, for its SW offshore area. Western Iberia has been well covered by the growing number of permanent seismic stations during the last decade, providing a large dataset. Using this dataset along with offshore seismograms of local earthquakes recorded by temporary ocean-bottom seismometers, and adopting the single backscattering

To determine the spatial distribution of earthquake potential along the active Himalayan arc, we utilize GPS measurements and earthquake data. We derive horizontal velocity field and 2-D strain rates from a new set of 41 regional GPS stations along with 446 published velocities. We convert these strain rate tensors to geodetic moment rate build-up within 24 contiguous segments and compare to the seismic

Many seismic surveys and exploration wells have been conducted in offshore Abu Dhabi, United Arab Emirates. However, the Neoproterozoic basement and the Infracambrian Hormuz salts were not imaged or penetrated by seismic and well data. To delineate the morphology of the basement and distribution of salt bodies, we applied a 3-D constrained inversion method to aerogravity and aeromagnetic data covering

Abstract The paper reports geochemical and mineralogical data on ores of the Briketno-Zheltuhinskoe U–Mo–Re deposit, which is confined to the Visean paleochannel coal-bearing sandy sediments of the Moscow lignite basin. In addition to main ore elements (Re, Mo, U, and Se), the ores have elevated contents of the following metals (in order of decreasing abundance): Zr, Zn, Mn, Ni, As, Co, V, Pb, Y, Cu

Abstract The paper presents the results of studying the Pesochansk brown coal deposit located in the central Dnieper–Donets coal-bearing area. The sedimentary cover of this area is characterized by the presence of salt structures, one of which is the Pesochansk stock. The subsidence trough of this pre-Paleogene structure was filled with the Paleogene–Neogene sediments containing three brown coal seams

Abstract The article characterizes some geochemical proxies of endo- and exospheric processes in sedimentary sequences and analyzes their average values in Upper Precambrian clayey rocks in the South Urals. It is shown that a gradual decrease of the Th/Scaver value in Lower Riphean (Mesoproterozoic) ~1750–1300 Ma ago rocks correlates to a certain extent with the assembly and disintegration of the Columbia/Nuna

Abstract Organogenic buildups named as carbonate mounds are widespread in Lower Permian deposits in the northern Timan–Pechora basin and are of great interest to the oil-and-gas industry as natural hydrocarbon reservoirs. Their distribution and textural features were controlled by seabed morphology, sea level changes, and specific paleoecology of the Early Permian period. In contrast to classic reefs