Abstract Unconsolidated sediments can amplify ground motions, increasing seismic hazard. Horizontal-to-vertical spectral ratios derive the thickness of overlaying stiffer bedrock. However, additional information about shear velocities and calibration with other structural is necessary. Here, we propose a strictly ambient noise-based workflow that map depth without from data sources. Rayleigh wave dispersion curves ellipticities are derived three-component beamforming noise combined...

The König-project is funded by the German state with aim to develop a calibrated and virtual measurement laboratory enhance methods based on ultrasound measurements that find application in determination of flow velocity or particle movement. By comparing results controlled real-world experiments numerical simulations, understanding interaction between ultrasonic waves fluid intended be improved. amount scatterers within fractured medium directly affects  the effective...

Accurate subsurface seismic velocities are crucial for drilling exploration wells, exploring geothermal resources, or locating events. Due to their dispersive nature and prevalence in ambient noise, surface wave can be used obtain shear beneath arrays. Localized velocity anomalies indicate the presence absence of fluids; Temporal variations changes fluid content poisson ratio over time, i.e. during operations. Three-component noise beamforming (B3Am) detects waves passing arrays...

Ensuring the structural integrity of concrete, particularly in critical infrastructures like bridges, requires reliable methods for identifying and localizing small-scale defects, such as fractures or damage. This study introduces a non-destructive evaluation technique that leverages principles both active ultrasonic testing passive seismic to enhance defect localization. The method, time-reverse imaging (A-TRI), compares waveforms recorded from concrete specimens their intact altered states...

Geothermal energy offers great potential for supplying heat to the large district heating networks common in central Europe and is a viable substitute fed into by coal-fired power plants that will soon be decommissioned. In Lower Rhine Embayment, efforts are ongoing explore region's geothermal potential. To facilitate any future drilling testing activities, we contribute seismotectonic prescreening of study area. However, because various anthropogenic noise sources, including open pit...

Monitoring induced seismicity is an indispensable part of risk management during the creation and operation enhanced geothermal systems. Due to relative scarcity manually labeled, informative datasets seismicity, it can be challenging evaluate performance monitoring tools ahead time. We have created continuous synthetic seismic waveform data for sequence at Utah Frontier Observatory Research in Geothermal Energy (FORGE). The are based on a catalog that mimicks injection-induced FORGE...

Geothermal resources represent a significant opportunity for clean baseload energy in Europe, yet their development remains largely untapped. A key barrier to expanding geothermal is the challenge of greenfield exploration, where traditional active seismic methods face high costs, complex logistics, and limited depth resolution, which elevate project risks. Recently, ambient noise tomography, passive imaging technique, has emerged as promising alternative due its affordability, scalability,...

Geothermal energy is an essential low-carbon resource for the transition. The subsurface characterization of geothermal fields vital expansion this resource. Often, faults and fractures provide secondary permeability required hydrothermal circulation. Anisotropy in ambient seismic noise wavefield a novel method constraining these within settings at inexpensive cost.We use code package B3AM to perform three-component (3C) beamforming noise. It array-based which extracts polarisation, azimuths...

The Matlab toolbox B3AM (B3AMpy for Python) three-component beamforming of ambient noise data provides a means to characterise the seismic (noise) wavefield and image near-surface properties quickly cheaply. Provided with array data, outputs dispersion curves pro-/retrograde Rayleigh Love waves, estimates composition propagation direction as function frequency, can be extended surface wave anisotropy analysis. We present recent results from gathered at geothermal sites in Netherlands, UK,...

Abstract To integrate structural subsurface models and smooth seismic velocity models, they need to share common features resolutions. Here, we propose a new approach, Depth Assessment from Rayleigh Wave Ellipticities (DARE), for estimating the depth of sudden changes ambient‐noise multi‐mode waves applicable wide range frequencies. At frequencies where have an extremum in ellipticity, phase can be used estimate changes. We test our approach theoretically, numerically, on real data two...

We have developed an approach to determine the time-dependent moment tensor and origin time in addition commonly derived locations of seismic events using reverse imaging (TRI). It is crucial locate characterize occurring microseismicity without making a priori assumptions about sources fully understand subsurface processes inducing seismicity. Low signal-to-noise ratios (S/Ns) often force standard methods make or only selected larger magnitude events. In TRI, microearthquakes are located by...

Summary Characterizing faults in geothermal fields is essential for the energy transition, as enable efficient heat flow throughout reservoir. Three-component (3C) beamforming, an ambient seismic noise technique, a cheap and effective way to analyse fault-related anisotropy by observing surface wave velocities. 3C beamforming extracts type, direction phase velocities of coherent waves function frequency, which provides understanding Anisotropic have been shown be caused presence faults,...

We introduce the MATLAB toolbox B3AM for beamforming of three-component ambient noise array data. explain theory behind and polarisation analysis in particular, provide an overview workflow, discuss output using a worked example. The strength presented code package is multiple beam response maps from time windows. Hence, it provides statistical information about wavefield recorded over period time, such as ratio surface to body waves, average dispersion velocities, or dominant propagation...

Abstract. Passive seismic analyses are a key technology for the exploration and monitoring of subsurface reservoirs. Searching alternative resources in framework energy transition is creating surge identifying as many potential sites possible suitable geothermal exploitation. The Lower Rhine Embayment, at western border North Rhine-Westphalia Germany, an extensional system with very high area experiences moderate but continuous natural seismicity. Here, we report on passive dataset recorded...

Ultrasonic measurements are used in civil engineering for structural health monitoring of concrete infrastructures. The late portion the ultrasonic wavefield, coda, is sensitive to small changes elastic moduli material. Coda Wave Interferometry (CWI) correlates these coda with wavefield recorded intact, or unperturbed, specimen reveal amount velocity change that occurred. CWI has potential detect localised damages and global reductions alike. In this study, sensitivity different types...

Coda wave interferometry usually is applied with pairs of stations analyzing the signal transmitted from one station to another. A feasibility study was performed evaluate if single could be used. In this case, reflected coda a zone identified analyzed. Finite-difference simulations propagation were used whether ultrasonic measurements detect velocity changes in such up depth 1.6 m highly scattering medium. For aim, 1D convolutional neural networks for prediction. The crack density, length,...

Ultrasonic measurements are used in civil engineering for structural health monitoring of concrete infrastructures. The late portion the ultrasonic wavefield, coda, is sensitive to small changes elastic moduli material. Coda Wave Interferometry (CWI) correlates these coda with wavefield recorded intact, or unperturbed, specimen reveal amount velocity change that occurred. CWI has potential detect localized damages and global reductions alike. In this study, sensitivity different types...

SUMMARY The estimation of the source–location accuracy microseismic events in reservoirs is significant importance. Time-reverse imaging (TRI) provides a highly accurate localization scheme to locate by time-reversing recorded full wavefield and back propagating it through velocity model. So far, influence station geometry model on not well known. Therefore, sensitivity maps are developed using geothermal site Los Humeros Mexico evaluate spatial variability accuracy. Sensitivity created with...

The location and focal mechanism of microseismicity induced during fluid injection experiments in geothermal wells can be used to infer the extent fracturing orientation local stress field. Passive seismic instrumentation is typically deployed at surface boreholes around site monitor microseismic activity. Recent methodological advancements enable locating often thousands events a timely fashion. However, determination mechanisms limited selected number larger-magnitude events.  ...

Summary Seismic ambient methods have proven increasingly useful for site characterisation and seismic hazard assessment. Methods such as the Horizontal-to-Vertical Spectral Ratio (HVSR) technique been used to determine resonance frequency of shallow sedimentary layer. In this abstract, we use a three-component beamforming algorithm decipher composition noise. We show that by doing that, can better understand major contributor HVSR curve subsequently map thickness top layer either Love wave...

<p>We show that the geometry of a seismic array affects estimates velocity and propagation direction ambient noise wavefields measured with beamforming techniques. We demonstrate how this results in apparent anisotropy present first approaches to mitigate effect.</p><p>Beamforming is an technique originating from earthquake seismology has become increasingly popular analyse wavefield goal characterise sources (e.g., regions origin Love Rayleigh...

ABSTRACT In this paper, the methods of digital rock physics are applied to determine pressure‐dependent effective thermal conductivity in samples. Simulations performed with an in‐house three‐dimensional finite volume code. first step, four numerical models derived from a given tomographic scan Berea sandstone. Consequently, simulations at ambient conditions and validated experimental data. second new workflow for determination samples is elaborated, tested calibrated. Results originating...

Surface wave dispersion curves derived from ambient noise recordings are frequently used to invert for subsurface velocity information. Rayleigh ellipticities and phase velocities exploited, sometimes jointly inverted, the structure beneath seismic arrays. Wavelengths of surface waves become large at low frequencies are, thus, sensitive great depths, but provide only very smooth profiles. However, sudden increases in particular interest delineate extent reservoirs, i.e., by sub-horizontal...

To integrate structural subsurface models and smooth seismic velocity models, they need to share common features resolutions. Here, we propose a new approach for estimating the depth of sudden changes from ambient-noise multi-mode Rayleigh waves applicable wide range frequencies. Approximating size shape so-called energy ellipse at frequencies where ellipticity has an extremum allows us derive as half height ellipse. We test our theoretically, numerically, on real data two geothermal sites...