Geophysical Journal International

SummaryIn this work, we address the characterization of porosity and water saturation in a synthetic model of a shallow alluvial subsurface using frequency electromagnetic and seismic data. The inversion method employs a Gauss-Newton scheme, where the Jacobian of the merged seismic and electromagnetic data is formulated with respect to the spatially heterogeneous petrophysical parameters. This is made possible by introducing realistic petrophysical relationships, which significantly reduce the number of unknowns in the inverse problem and incorporate a strong prior correlation between the information contained in both data types regarding the subsurface composition. The results obtained show that this Simultaneous Joint Petrophysical Inversion (SiJPI) produces reconstructions with clear improvements compared to Independent Petrophysical Inversion (IPI). Indeed, it greatly enhances the spatial resolution of subsurface mapping, as well as the quantitative estimation of porosity and saturation.

SummaryThe Xiaojiang fault system (XJFS) is located in the southeastern margin of the Tibetan Plateau, which has been considered as an ideal site to explore the traces and effects of past tectonic activity. In this study, we obtain a high-resolution P-wave velocity and azimuthal anisotropy model of the upper crust beneath the XJFS, utilizing the 2D Pg wave tomography method including both station and event depth corrections. The upper crust displays obvious heterogeneity of both azimuthal anisotropy and P-wave velocity underlying the XJFS. The large azimuthal anisotropy beneath the XJFS, especially the regions where several faults interact, suggests the cracks are widely distributed. Generally, the upper crust is featured by several high-velocity bodies separated by low-velocity anomalies. The high-velocity bodies are speculated to be related to the remnant magmatic rocks of the Emeishan large igneous province. The low-velocity anomalies are interpreted to represent fault damage zones which could be attributed to the strike-slip faulting/shearing along the faults and upwelling of deeply-sourced partial melts and fluids. The present tectonic activity in the XJFS is characterized by rigid block extrusion along strike-slip faults in the upper crust, which is consistent with the rigid block extrusion model. We further propose a tectonic model to display the evolution of the upper crust beneath the XJFS, in which the faults and fluids activity plays an essential role.

AbstractGeophysical measurements such as induced polarization (IP) are invaluable for understanding the physical properties of rocks, including pore structure, hydraulic properties, and mineral content. However, collecting reliable IP measurements from low-permeability rocks poses substantial challenges due to the difficulty of saturating their tight pore spaces. Additionally, IP measurements on rocks that are not cored to fit conventional sample holders, or are irregularly shaped, are particularly difficult to obtain. In this work, we address these challenges through (1) the use of reliable saturation procedures developed for low-permeability samples, and (2) a molding procedure designed to overcome the difficulties of measuring IP on irregularly shaped or broken rock cores. Core-scale gravimetric porosity measurements closely match values obtained from destructive mercury intrusion porosimetry (MICP) on rock fragments, confirming the effectiveness of the saturation procedure. Direct comparisons of IP measurements between molded and unmolded cores demonstrate that the molding process does not significantly alter the intrinsic electrical response of the samples. Fully saturated mudstones exhibit strong statistically significant relationships between the mean relaxation time (τmean) and permeability (k), and between effective porosity (1/formation factor, F) and interconnected porosity (ϕ) (Archie’s law). Conversely, partial saturation due to ineffective saturation methods introduces substantial scatter to these petrophysical correlations. Overall, these findings underscore the potential of these methods to enhance the reliability and accuracy of SIP measurements on challenging rock samples.

SummaryOn January 18, 2021, a blind mid-crustal Mw ∼6.4 earthquake occurred near San Juan, Argentina. The observation of associated ground deformation with single interferograms is obscured by strong tropospheric signals. We apply appropriate corrections to the data and reconstruct the deformation field associated to the event through InSAR time series approach. We show it is possible to retrieve this signal to invert the fault parameters. The observed ground deformation is consistent with a high angle NW-dipping fault plane at a centroid depth of ∼19 km. The geometry of this fault supports the reactivation of pre-existing structures within the Cuyania Terrane, suggesting a direct structural connection and strain transfer to the actively deforming, east-vergent Precordillera front. We analyze our findings to deduce a static friction coefficient ≤0.3 for mid-crustal faults of the region.

SummaryWe refined the Attenuated ProPagation of Local Earthquake Shaking (APPLES) ground-motion-based earthquake early warning (EEW) approach, and directly compare APPLES performance with that of the source-characterization-based U.S. ShakeAlert EEW system for a suite of historical earthquakes in the U.S. West Coast and Japan. APPLES is an extension of the Propagation of Local Undamped Motion (PLUM) algorithm in which observed shaking intensity at seismic stations is used to forward-predict intensity distributions to surrounding areas using an attenuation model derived from an intensity prediction equation. We test new configuration options within APPLES, such as using the second highest estimated ground motion rather than the maximum, to better match median ground-motion observations and reduce alerts for small magnitude earthquakes, both of which are key alerting priorities within ShakeAlert. We evaluate these configurations alongside ShakeAlert by comparing the ground-motion estimation accuracy and available warning times relative to station observations and ShakeMap distributions. Our preferred APPLES configuration produces accurate ground-motion estimates and corresponds better with median observations compared to ShakeAlert’s estimates. This preferred configuration substantially reduces alert issuance for M < 5.0 earthquakes compared to the previous APPLES configuration, and alert-release criteria can further restrict alerts to primarily M ≥ 5.5 earthquakes without requiring magnitude estimation. Prioritizing matching median-observed ground motions may reduce APPLES warning times compared to configurations that were tuned to avoid missed alerts (such as those that use the maximum estimated ground motions), which can lead to shorter warning times compared to ShakeAlert for the same alert threshold. However, station-based warning time assessments demonstrate that APPLES can outperform ShakeAlert for high target thresholds. APPLES is a simple, independent EEW approach that may improve the robustness of EEW for the West Coast of the U.S.

SummaryMetallic infrastructure, such as steel sheet situated within landfills, poses significant challenges to accurate tracking of leachate using induced polarization (IP) methods. The application of IP method is efficient to delineate leakage; however, the presence of metallic structures can cause an interference on the survey and generate high-chargeability anomalies as observed in field survey. To comprehensively validate the interference caused by steel sheets, both numerical and empirical field tests were conducted. As expected, both results demonstrate that interference diminishes as the distance between survey line and metallic structure increases. Additionally, at consistent intervals, the chargeability values inverted using integral chargeability (IC) exhibit a monotonic increase with depth. Moreover, the interference induced by metallic structures is also affected by the controlling factors (i.e. depth, width and thickness) of the structure alongside the intrinsic resistivity and chargeability. Strategic utilization of the size, chargeability, and spatial positioning of metallic structures relative to survey lines can significantly enhance background polarization. This approach offers a promising framework for improving the spatial resolution of subsurface targets exhibiting low polarization effects. The optimization of survey line placement, which must consider the dimensions and electrical properties of metallic structures such as steel sheets, is essential for accurately characterizing landfill leachate using the IP method.

SummaryNorthern Europe experiences vertical land motion and sea level changes that deviate from the average as a consequence of past changes in ice sheet cover in Fennoscandia and the British Isles. The process, called Glacial Isostatic Adjustment (GIA), is controlled by the subsurface structure. Numerical models of GIA can be compared to observations of uplift or past sea level changes to constrain the subsurface structure, and such models can also be used to correct present-day sea level observations to reveal sea level changes due to climate change. GIA models for northern Europe usually adopt a homogeneous upper mantle viscosity even though seismic studies indicate contrasting elastic lithosphere thickness and upper mantle structure between Northwestern Europe and Eastern Europe. This raises the question whether the effect of lateral variations in structure (3D viscosity) can be detected in observations of GIA and whether including such variations can improve GIA model predictions. In this study we compare model output from a finite element GIA model with 3D viscosity to observations of paleo sea level and current vertical land motion. We use two different methods to derive 3D viscosities, based on seismic velocity anomalies and upper mantle temperature estimates. We use three different reconstructions of the Eurasian ice sheet, one based on an inversion using a 1D model, and two others based on glacial geology and modelling. When we use these two reconstructions, we find that the data are fit better using 3D viscosity models. Models with two separate 1D viscosities for Fennoscandia and for the British Isles cannot replicate a 3D model because a 3D model redistributes GIA-induced stresses differently from a combination of models with separate 2D viscosities. The fit to data across Fennoscandia is improved when, as indicated by seismic models, the upper mantle viscosity is higher than for the rest of Northern Europe. The best fit is obtained with a model with dry olivine rheology, in agreement with other evidence from Fennoscandia.

SummaryIn both onshore and offshore seismic exploration, seismic source localization plays a crucial role in ensuring operational safety and environmental protection. With the continuous advancement of the Marchenko method in the fields of seismic migration and internal multiple elimination, this paper investigates a seismic source localization method based on the Marchenko method, aiming to further extend application domain of this method. The key to this method lies in the data reconstruction based on convolution operations. The conventional Marchenko method is then applied to obtain a seismic profile, which includes the location of the seismic source. In the experiments, this study first uses an anticline model to simulate seismic source localization in onshore seismic exploration. The results show that the proposed method can accurately estimate both the distance to the seismic source and its depth. Furthermore, in large-scale marine model experiments, the method is also able to reliably determine the distance between the seismic source and the observation stations.

SummaryFor the interpretation of Spectral Induced Polarization spectra, the determination of the Relaxation Time Distributions (RTD) can be useful, for instance to extract the grain size distribution. However, this is an ill-posed problem, and retrieving the RTD often requires regularization during the inversion process. In this note, we use Bézier curves and simulated annealing to determine the RTD. The procedure that does not require any regularization nor smoothing, by reducing the number of parameters thanks to Bézier curves which are intrinsically continuous and infinitely derivable. We successfully applied our methodology to three examples (Cole-Cole model, Davidson-Cole model, and an experimental spectrum), demonstrating its interest and efficiency.

SummaryThe extension of direct current resistivity methods to induced polarization methods has enriched the tools available for subsurface exploration. This enrichment involves an increase in the number of parameters used in the models, as well as addressing different physical phenomena than those observed with direct current. Accounting for non-linearities, if they exist, can further enhance the sophistication of our models. Non-linearities are often observed, particularly in laboratory experiments. However, we question their origin, and the experiment described here suggests that the non-linearities observed under typical experimental conditions may be artifacts related to the electrodes, rather than reflecting the actual response of the subsurface. Indeed, we first replaced the polarizable injection electrodes with non-polarizable electrodes. The non-linearities observed due to the presence of harmonics were significantly reduced. Then, we replaced the voltage control with a current control, which completely eliminated the non-linearities still present.We know that it is impossible to prove the non-existence of a phenomenon that does not exist. This fundamental epistemological principle (as pointed out by Russell and Popper) means that we are not claiming that nonlinearity does not exist. We are simply describing an experiment that can raise doubts about its existence.

SummaryWe present and validate an efficient GPU-accelerated solver for seismic wave propagation in three-dimensional elastic media. The solver achieves up to a 372× speedup relative to a CPU implementation and supports forward simulations on grids ranging from 100 million to 1 billion cells. It is based on a velocity-stress, first-order formulation of the elastodynamic wave equation and supports kilometer-scale models with layered isotropic and anisotropic structure. We validate the solver by comparing synthetic seismograms to analytical solutions from a propagator matrix method in axisymmetric media. Simulations include moment-tensor sources for a 2017 nuclear explosion and collapse in North Korea, and a magnitude ∼4 earthquake near Linthal, Switzerland (6 March 2017). Anisotropic effects for the Swiss event are modeled using rotated orthorhombic stiffness tensors derived from laboratory measurements of gneiss. Projection onto orthorhombic symmetry enables solver compatibility. We find that anisotropy changes waveform polarity, amplitude, and phase at near-source stations. Unscaled laboratory values produce polarity reversals, while velocity-rescaled tensors correct them. These results demonstrate the impact of anisotropy on waveform modeling and indicate that simplified 1D isotropic models may be insufficient for complex crustal settings. We review how structural effects, including anisotropy and 3D heterogeneity, contribute to transverse-component energy in the 2017 DPRK explosion and discuss implications for seismic source classification.

AbstractTransient stress changes from seismic waves of distant earthquakes can promote local fault slip, a phenomenon referred to as remote dynamic triggering. This study examines the remote triggering susceptibility of faults in the Lower Rhine Embayment (LRE) in the Weisweiler region, Germany, a proposed site for geothermal energy production. Assessment of remote triggering can guide industrial operations to assess seismic hazard and mitigate risks associated with fault reactivation caused by small stress perturbations. We select a set of 23 candidate mainshocks from global earthquake catalogs that produce peak ground velocities (PGVs) that exceed 0.02 cm/s in the LRE. The magnitude of these mainshocks ranges from 5.4 to 9.1, epicentral distances range from 50 to 12,300 km, and back azimuth ranges from 16○ to 350○ with a maximum azimuthal gap of 91○. The candidate mainshocks generated PGVs locally from 0.02 to 0.28 cm/s (compared to typical threshold values ranging from 0.02 to 6 cm/s), corresponding to dynamic stress (σpd) values of 1.4 to 26 kPa. We use P-statistics and waveform data from local seismic stations to identify seismicity rate changes and uncatalogued earthquakes that were potentially triggered by the passing mainshock waves. The analysis reveals a statistically significant increase in seismicity rates following four mainshocks: the 1992 Mw5.4 Roermond, Netherlands, 2021 Mw8.2 Chignik, Alsaka, USA, 2023 Mw7.6 Kahramanmaraş, Republic of Türkiye, and 2025 Mw8.8 Kamchatka, Russia earthquakes. The 1992 Roermond mainshock triggered earthquakes within 50 km of its epicenter that were clustered between the Feldbiss and Sandgewand faults. The same area experienced a triggered earthquake sequence following the Chignik mainshock, suggesting that future detailed monitoring in this area may be warranted. The Roermond aftershock distribution can be divided two groups of events, including 61 that occur on the fault and in the near-field, which can be explained by static-stress increase and fluid diffusion. Another 32 remote aftershocks occurred that are consistent with secondary triggering promoted by aseismic slip propagation. The alignment of triggering mainshock back azimuths with the dominant strike direction of regional faults suggests that the orientation of incoming seismic waves is an important factor influencing susceptibility. Despite evidence of triggering, the majority of mainshocks (19 out of 23) were not followed by detectable seismicity-rate changes in the LRE, highlighting the complexity of conditions that lead to remote dynamic triggering. The study area does not respond to a triggering stress threshold, suggesting that non-linear, or a combination of linear and non-linear effects, dominate possible triggering mechanisms. Although the LRE does not respond to a clear triggering threshold, this study demonstrates that peak dynamic stress perturbations of approximately 1.4 kPa or greater can still trigger earthquakes. But, susceptibility is modulated by additional factors such as fault orientation, earthquake fault-zone properties, their state in the seismic cycle, and pre-existing stress state.

AbstractPhysics-informed neural networks (PINNs) face significant challenges in modeling multi-frequency wavefields in complex velocity models due to their slow convergence, difficulty in representing high-frequency details, and lack of generalization to varying frequencies and velocity scenarios. To address these issues, we propose Meta-LRPINN, a novel framework that combines low-rank parameterization using singular value decomposition (SVD) with meta-learning and frequency embedding. Specifically, we decompose the weights of PINN’s hidden layers using SVD and introduce an innovative frequency embedding hypernetwork (FEH) that links input frequencies with the singular values, enabling efficient and frequency-adaptive wavefield representation. Meta-learning is employed to provide robust initialization, improving optimization stability and reducing training time. Additionally, we implement adaptive rank reduction and FEH pruning during the meta-testing phase to further enhance efficiency. Numerical experiments, which are presented on multi-frequency scattered wavefields for different velocity models, demonstrate that Meta-LRPINN achieves much faster convergence speed and much higher accuracy compared to baseline methods such as Meta-PINN and vanilla PINN. Also, the proposed framework shows strong generalization to out-of-distribution frequencies while maintaining computational efficiency. These results highlight the potential of our Meta-LRPINN for scalable and adaptable seismic wavefield modeling.

AbstractP-wave reflections from the 410- and 660-km mantle discontinuities are visible in stacks of ambient noise cross-correlation functions of USArray stations spanning the contiguous United States. The reflections are most visible on the vertical components at frequencies between 0.1 and 0.3 Hz during low-noise periods, which generally occur during the summer months in the northern hemisphere. Common reflection point stacking can be used to resolve apparent lateral differences in discontinuity structure across the continent and suggests the possible existence of sporadic reflectors at other depths. Visibility of the 660-km reflector is correlated with faster P-wave velocities at similar depth in a tomographic model for North America. However, the lack of clear agreement between these P-wave ambient noise features and prior mantle-transition-zone imaging studies using other methods suggests caution should be applied in their interpretation. Ambient noise sources from the southern oceans may not be distributed uniformly enough for cross-correlation stacks to provide unbiased estimates of the true station-to-station P-wave Green’s functions. However, the clear presence of 410- and 660-km reflections in the ambient noise data suggests that it should be possible to unravel the complexities associated with varying noise source locations to produce reliable P-wave reflection profiles, providing new insights into mantle structure under the contiguous United States.

AbstractSeismic wave propagation in poro-viscoelastic anisotropic media is of practical importance for exploration geophysics and global seismology. Existing theories generally utilize homogeneous plane wave theory, which considers only velocity anisotropy but neglects attenuation anisotropy and wave inhomogeneity arising from attenuation. As a result, it poses significant challenges to accurately analyze seismic wave dispersion and attenuation in poro-viscoelastic anisotropic media. In this paper, we investigate the propagation of inhomogeneous plane waves in poro-viscoelastic media, explicitly incorporating both velocity and attenuation anisotropy. Starting from classical Biot theory, we present a fractional differential equation describing wave propagation in attenuative anisotropic porous media that accommodates arbitrary anisotropy in both velocity and attenuation. Then, instead of relying on the traditional complex wave vector approach, we derive new Christoffel and energy balance equations for general inhomogeneous waves by employing an alternative formulation based on the complex slowness vector. The phase velocities and complex slownesses of inhomogeneous fast and slow quasi-compressional (qP1 and qP2) and quasi-shear (qS1 and qS2) waves are determined by solving an eighth-degree algebraic equation. By invoking the derived energy balance equation along with the computed complex slowness, we present explicit and concise expressions for energy velocities. Additionally, we analyze dissipation factors defined by two alternative measures: the ratio of average dissipated energy density to either average strain energy density or average stored energy density. We clarify and discuss the implications of these definitional differences in the context of general poro-viscoelastic anisotropic media. Finally, our expressions are reduced to give their counterparts of the homogeneous waves as a special case, and the reduced forms are identical to those presented by the existing poro-viscoelastic theory. Several examples are provided to illustrate the propagation characteristics of inhomogeneous plane waves in unbounded attenuative vertical transversely isotropic porous media.

AbstractDeep learning (DL) approach has gained attention for earthquake (EQ) detection. To alleviate the problem of training data shortage, transfer learning (TL) provides a useful framework to adapt pre-trained models, typically through tuning of model parameters. Nonetheless, the current practice still requires considerable data, which hinders its application where only a small number of data is available. Instead of TL, we propose a novel two-stage of model correction as a solution to this important and ubiquitous problem in EQ detection. In the proposed approach, a pre-trained DL model is directly applied to waveform data in the target domain (first stage), and the cases that are classified as an earthquake signal (i.e., positive cases) are further classified as positives and negatives using a non-DL classification method (second stage). Our classification method for the second stage is based on multiple clustering, which characterizes local waveform patterns in terms of amplitude scale in specific time segments that are inferred in a data-driven manner. This characterization captures complex high-dimensional waveform patterns in a low-dimensional space, which leads to the effective classification of true and false positives. Furthermore, the proposed method is useful when only true positive waveforms are labeled (PU classification). Both synthetic and real data analysis clearly demonstrated effectiveness of unsupervised waveform characterization of the proposed method.

AbstractFull-waveform inversion (FWI) is a powerful imaging technique that produces high-resolution subsurface models. In seismology, FWI workflows are traditionally based on seismometer recordings. The development of fibre-optic sensing presents opportunities for harnessing information from new types of measurements. With dense spatial and temporal sampling, fibre-optic sensing captures the seismic wavefield at metre-scale resolution along the cable. Applying FWI to fibre-optic measurements requires the reformulation of the forward and adjoint problems due to two fundamental differences to seismometer data: i) fibre-optic measurements are sensitive to strain rather than translational motion, and ii) they do not represent the motion at a single spatial point, but instead capture the average deformation over a pre-defined cable segment, known as the gauge length. Within this study, we derive the adjoint sources to perform FWI for data from distributed acoustic sensing (DAS) and integrated fibre-optic sensing (IFOS) that are based on moment tensors. Our formulation incorporates gauge-length effects, direction-dependent sensitivity and complex cable layouts. For the numerical simulations, we use a spectral-element solver that allows us to incorporate surface topography, and coupled viscoacoustic and viscoelastic rheologies. In illustrative examples, we present how our theoretical developments can be used in inversions of synthetic fibre-optic data generated for a realistically curved cable placed on irregular topography. As examples, we invert for source parameters, including moment tensor, location, and origin time for noise-free DAS data, noise-contaminated DAS data, and IFOS data. Further, we present the 3-D imaging results for the three data groups and further analyse the effect of scatterers on the FWI based on DAS data. In all example inversions, we compare how close the found model is to the known ground truth. The codes to produce these results are accessible and ready to be applied to real data inversions.

AbstractHigh-frequency induced polarisation, which measures the complex electrical conductivity in a frequency range up to several hundred kHz, is potentially suitable to detect and quantify ice in the frozen subsurface. In order to estimate ice content from the electrical spectra, a two-component weighted power mean (WPM) model has been suggested and applied to field-scale data. In that model, ice is one of the components, whereas the solid phase, residual liquid water and potentially air form the second component, called “matrix”. Here, we apply the model to laboratory data previously discussed in the literature, with the aim to assess the applicability of the model and to understand the behaviour of the frequency-dependent electrical conductivity. The data were measured on an unconsolidated sediment sample with 20.8% water content from the European Alps, and a consolidated sandstone with 16.6% porosity. Electrical spectra have been measured over a temperature range from approx. - 41 ○C to +20 ○C and a frequency range from 0.01 Hz to 45 kHz. We extend the original WPM model to account for low-frequency polarisation in form of a constant phase angle model. The measured data were fitted with the model by a least-squares inversion algorithm. In order to reduce the ambiguity, we constrained several of the nine underlying parameters by literature values, in particular for the electrical properties of water ice, and the expected ice content according to porosity or water content of the unfrozen sample. Both data sets can be well matched, corroborating the hypothesis that the model is in principle suitable to explain measured data of frozen samples in that frequency range. One important observation is that the mixing parameter, i.e. the power in the WPM model, which is controlled by the geometric arrangement of the two components, depends on temperature. For the unconsolidated sample it even becomes negative at the coldest temperature, which is important because negative shape factors relate to specific geometries. A second observation is that relatively large permittivities of the matrix are required to fit the data, suggesting that processes at the interface between solid/liquid phase and ice, which are not included in the volumetric mixing model, might be relevant and should be considered in future extensions of the model.

SummaryThe dominant forces shaping the unique geometries of flat slabs are still not fully understood. Knowing how the stress field changes with respect to the shape of the slab allows inferences of the dominant forces acting on the slab. In this study we calculated new models of the slab geometry and the intraslab stress field in the Pampean flat slab region of the Chile-Argentina Subduction Zone (latitude ∼25°36°S) where the Nazca Plate subducts together with the aseismic Juan Fernandez Ridge. To build the models, we used a catalog of 1,059 well-located slab earthquakes recorded by the SIEMBRA and ESP temporary seismic arrays and calculated 411 new focal mechanisms that were analyzed together with 407 focal mechanisms from other catalogs. Our results confirmed slab seismicity features such as a reverse dip (i.e. opposite to the subduction direction) of the seismicity band within the flat slab, two bands of descending seismicity, and two regions with an absence of earthquakes. These seismicity patterns express the shape of the slab and its hydration state, with more localized slab dehydration along the inland path of the Juan Fernandez Ridge relative to the surroundings. In one of the regions without earthquakes, the slab is most likely continuous and dry, while in the other one the slab is missing, in agreement with previous works that proposed a hole in the slab visible with other methods. A comparison between the stress field and the local slab dip from both our new model and a previous one (Slab2) indicates that the dominant forces acting on the flat slab are the slab pull and the ridge buoyancy. Finally, the shape of the flat slab is controlled by the geologic migration of the Juan Fernandez Ridge, making the flat slab four times wider than the ridge offshore, and by the competing forces of the slab pull and the ridge buoyancy that creates a notable flexure (bulge) resembling the geometry of the outer rise near the trench.

SummaryIn the analysis of Induced Polarization (IP) data, it is commonly assumed that induction effects (IE) are negligible. However, at higher frequencies, this assumption becomes increasingly invalid, posing challenges for IP measurements. High-frequency induced polarization (HFIP) extends the conventional IP frequency range beyond 100 kHz, allowing estimation of ice content by capturing the characteristic decrease in permittivity of water ice. This study focuses on the interpretation of HFIP data while accounting for IE. We modified an existing one-dimensional simulation code to evaluate HFIP responses over frozen ground with ice, both with and without the influence of IE. Our results demonstrate that IE can distort HFIP measurements in typical permafrost conditions, potentially obscuring the characteristic polarization behavior of water ice. two-dimensional IP inversion codes that account for IE are not routinely available. Even if they were, the simultaneous presence of IE and IP would likely complicate their application. We therefore propose to remove IE from the data, with the aim to use well-established two-dimensional SIP inversion routines. For this purpose, we implemented a one-dimensional inversion routine that includes IE as a frequency-dependent correction factor. The method is based on fitting a layered model to the data. Comparing the responses with and without IE, we calculate a correction factor which is subsequently used to remove IE from the original dataset. The method is conservative in the sense that features not well matched by the one-dimensional inversion are preserved and no information gets lost. We demonstrate the effectiveness of the method with synthetic data, as well as field datasets from an unfrozen site in Germany, and from permafrost peatlands in Scandinavia. We provide evidence from reciprocal measurements that cable coupling effects, not included in the correction procedure, have been effectively minimized by the acquisition system. We further show that high-frequency phase shifts are strongly influenced by IE, and that the correction methodology successfully restores the spectral response. By applying the approach to a measured dataset, we demonstrate that two-dimensional inversion of the corrected data with a well-established code is both feasible and robust. The resulting model deviates markedly from that obtained with uncorrected data, highlighting the critical role of the correction procedure for reliable interpretation.