Szymon Oryński

The long-term stability and reactivation potential of large landslides are primarily controlled by their deep internal structure, the geometry and connectivity of shear planes, fault systems, and subsurface hydraulic pathways. Despite their importance, these features remain difficult to investigate, and geophysical methodologies capable of resolving those at sufficient resolution and depth are still not fully established. This study addresses this challenge through a comprehensive, multi-method geophysical investigation of the Cisiec landslide, located in the Żywiec district of southern Poland.The study area comprises a forested clearing surrounded by meadow terrain, with the landslide moving predominantly east–northeast and exhibiting an elevation difference of approximately 100 m between its crown and toe. Annual monitoring campaigns, including drone-based photogrammetry and laser scanning, as well as geophysical measurements like seismic or resistivity tomography, conducted between 2018 and 2022, provided valuable insights into the general geometry and kinematics of the landslide. Still, process-understanding of the complex and non-linear landslide behaviour could not be fully obtained. These datasets allowed the construction of a preliminary structural models and indicated temporal variability in displacement patterns; however, the nature of movement along individual slip surfaces remained unresolved. In particular, it was unclear whether deformation occurred as a coherent, uniform displacement or as a progressive, sequential sliding process involving multiple layers or discrete blocks. Furthermore, the role of groundwater circulation within the landslide body and its influence on mechanical stability could not be conclusively determined.To overcome these limitations, we conducted advanced geophysical surveys during dedicated field campaigns in October 2024 and April 2025. The investigation integrated high-resolution seismic imaging based on Distributed Acoustic Sensing (DAS) with Spectral Ground Penetrating Radar (SGPR) and a suite of electrical and electromagnetic methods, including Electrical Resistivity Tomography (ERT), Frequency Domain Electromagnetics (FDEM), Time Domain Electromagnetic (TDEM) soundings, and Spectral Induced Polarization (SIP). Each technique was carefully selected and optimized to resolve complementary aspects of the landslide architecture, ranging from shallow deformation features to deeper structural controls and subsurface hydraulic pathways.The combined dataset provided a detailed, multi-scale image of the landslide, revealing significant spatial heterogeneity in both mechanical and hydrogeological properties. Seismic imaging resolved fine-scale structural and geomechanical variations, while electrical and electromagnetic methods highlighted zones of enhanced moisture content and groundwater flow. The results confirm a division of the landslide into three distinct kinematic zones and reveal previously unresolved shallow slip surfaces and groundwater-related effects. Notable observations include focused groundwater discharge at the lower slope and an anomalous signal attenuation zone near the crown, interpreted as evidence of microseismic activity and the development of a potential new failure zone. These findings demonstrate the value of integrated, high-resolution geophysical approaches for improving conceptual models of complex landslide systems and for supporting long-term hazard assessment.

Rapid changes in the cryosphere, including permafrost, glaciers, and snow cover, are increasingly altering polar environments, with significant implications for climate feedbacks, hydrology, ecosystem functioning, and biogeochemical cycles. In polar regions, these transformations are particularly pronounced in post-glacial landscapes, where surface and subsurface processes respond sensitively to ongoing climatic forcing.This study presents the results of long-term investigations of permafrost distribution and degradation in the Hornsund area (Svalbard), based on electrical resistivity tomography (ERT) surveys conducted between 2010 and 2025. Geophysical measurements were carried out across a range of geomorphological settings, including marine terraces, mountain slopes, coastal zones, and the forefields of retreating glaciers. The multi-site and multi-temporal ERT dataset enabled detailed identification and characterization of permafrost occurrence, thickness, and internal structure under varying environmental conditions.The 15-year observation period provides a robust basis for assessing spatio-temporal changes in permafrost distribution and for identifying signs of progressive degradation in selected areas. Observed resistivity patterns indicate a reduction in permafrost continuity and thickness. These results contribute to improved quantification of the impacts of permafrost change on hydrological regimes, sediment and nutrient transport, coastal stability, and ecosystem dynamics. The findings highlight the importance of long-term geophysical monitoring in reducing uncertainties associated with projections of cryosphere climate interactions and their broader environmental consequences.

The interplay between internal structure, deformation mechanisms, and subsurface hydrogeological processes controls the long-term stability of large landslides. A key unresolved issue is whether infiltrating groundwater is confined to the landslide body or can migrate into the underlying bedrock along deep-seated structural discontinuities. This problem is particularly relevant in areas underlain by steeply dipping flysch formations, where structural anisotropy may promote vertical groundwater connectivity and influence landslide reactivation. This study focuses on the Cisiec landslide in the Żywiec district of southern Poland, aiming to identify groundwater percolation pathways and their relationship to slope deformation. The landslide affects a ski slope located in a forest–meadow transition zone and moves predominantly east–northeast, with an elevation difference of approximately 100 m. Previous monitoring indicated complex kinematics but did not resolve the depth extent of groundwater infiltration or its coupling with deep geological structures.We apply an integrated electromagnetic approach explicitly designed to resolve processes across complementary depth ranges. Shallow groundwater dynamics were monitored using time-lapse Frequency Domain Electromagnetics (FDEM), which is sensitive to depths of approximately 0–3 m and was repeated over a three-year interval. FDEM conductivity variations were used to map spatial and temporal patterns of near-surface water percolation within the landslide body. In addition, the in-phase component of the FDEM signal was exploited to detect positional changes of buried infrastructure on the ski slope. When combined with high-precision Differential GPS (DGPS) measurements, these data provided quantitative constraints on surface displacement and landslide activity. To resolve the intermediate-depth range and provide robust constraints for deep imaging, Electrical Resistivity Tomography (ERT) was conducted along five profiles across the landslide. The resulting resistivity sections, which image the subsurface to approximately 30 m depth, were incorporated as a priori resistivity constraints and starting models for the inversion of Audio-Magnetotelluric (AMT) data. This constrained inversion strategy significantly reduced ambiguity in the AMT results and ensured consistency between shallow, intermediate, and deep resistivity structures.AMT imaging extended the investigation below 30 m depth and enabled the construction of a three-dimensional resistivity anomaly model of the landslide and its geological basement. The model reveals pronounced, near-vertical resistivity structures associated with the Carpathian flysch beneath the landslide, interpreted as preferential pathways for deep groundwater migration. The integrated interpretation of FDEM, ERT, and AMT data indicates that infiltrating groundwater is not restricted to the landslide mass but can penetrate into the bedrock along steeply oriented discontinuities. This hydrogeological connectivity between shallow infiltration zones and deep structural features provides a plausible mechanism for delayed landslide reactivation and long-term slope instability. The study highlights the importance of multi-scale, constraint-driven electromagnetic imaging for improving hazard-relevant conceptual models of complex landslide systems.

This presentation summarizes a project focused on the seismic imaging and time-lapse monitoring of dams, embankments, and landslides using seismic and complementary geophysical methods. These structures are particularly sensitive to environmentally induced changes, such as variations in water saturation driven by climate variability and human activity, which can significantly affect their stability and long-term performance.This study presents the results of repeated geophysical surveys conducted in 2023 and 2024 to investigate seepage and under-seepage processes in critical infrastructure related to the Rybnik water reservoir in southern Poland. To analyse the state of the embankment and dam, we used a combination of seismic, CCR, and ERT methods, supported by observations with a DAS system and an innovative Spectral GPR. Using repeated surveys, we were able to image not only spatial inhomogeneities but also changes in the structure related to different water tables and water saturation in the studied Earth-filled objects. Moreover, between the two surveys, maintenance works were performed to limit excessive seepage in the embankment. This action reduced seepage by 30%, but geophysical data enabled a spatial evaluation of the works and identified areas that require future monitoring.Besides standard analysis in the form of ERT and seismic tomography, we utilised high-resolution seismic data recorded at a 2 m horizontal spacing for reflection imaging. This allowed us to recognise geological structures below man-made structures and the effects of the old river bed located beneath the construction. An additional 3C geophone was used for the seismic survey, allowing for precise analysis of P and S waves. This resulted in Vp/Vs analysis of the objects. Moreover, the combination of P and S wave reflection images provides insight into detailed structures that cannot be recognised with standard methods.Finally, we utilised the DAS system to further increase the spatial resolution of the seismic data. A comparison of DAS and horizontal geophone data shows that DAS provides long-term monitoring capabilities, essential for ongoing structural health assessments and geohazard detection. For example, the multichannel analysis of surface waves (MASW) using DAS data clearly identifies S-wave velocities down to 13 m with an RMS error of 3.26%, compared to an RMS error of 6.2% for geophone data.In addition, seismic tomography was applied to the Cisiec landslide (Żywiec district, southern Poland), where time-lapse velocity models are used to track hydrologically driven changes in subsurface properties associated with slope instability.This research was funded by National Science Centre, Poland (NCN) project number 2022/45/B/ST10/00658.

This study aimed to investigate and characterize the subsurface geophysical signatures associated with 20th‐century interwar housing developments in the Koło district of Warsaw, Poland, to provide new insights into the area's social history. These were largely destroyed during World War II and were part of a broader national initiative to address homelessness and the severe housing shortages at the time. The study methods used archival records and remote sensing data to identify the survey site, which was a current public park, where traditional excavation was not feasible. A phased geophysical site survey was then used to create a frequency domain electromagnetic method (FDEM) grid, providing key information on spatial patterns of geophysical response potentially associated with building foundations and related infrastructure. Secondary Ground‐Penetrating Radar (GPR) survey profiles then provided higher resolution information on foundation positions, although the data were geophysically noisy. This non‐invasive approach supports the preservation of the site's integrity and deepens the understanding of Warsaw's urban history, contributing valuable information for future archaeological and historical studies. The findings highlight the effectiveness of combining multiple datasets in non‐invasive archaeological research, particularly in urban settings where traditional excavation is not feasible.

In this study, the internal structure and seasonal variations of cryo‐hydrogeological features were investigated in the Fuglebekken catchment, located near the Polish Polar Station Hornsund in Svalbard. Over a few years, rising air temperatures and intensified water circulation have significantly altered the distribution, extent, and state of ground temperature and groundwater. Spatial variations in these changes are influenced by surface and groundwater presence and flow patterns. Accelerated permafrost degradation and reduced seasonal soil freezing lead to a transition from a primarily frozen winter state to a partially thawed state with year‐round active groundwater flow paths. To capture spatial variations in changing cryo‐hydrogeological conditions, a multi‐source approach was employed, integrating in situ borehole and piezometer data with geophysical techniques including Ground Penetrating Radar (GPR) and Frequency Domain Electromagnetic Method (FDEM). The main goal was to identify unconfined and confined aquifers, and the permafrost table. Changes in the active layer thickness between areas with and without water influence were estimated. The findings contribute to the knowledge of high‐latitude hydrology and the impact of climate change on permafrost degradation and associated groundwater dynamics.

SUMMARY: Direct current electrical resistivity tomography (ERT) is a widely used geophysical method for near-surface investigations, offering high-resolution imaging for geological, engineering and environmental applications. While traditional ERT surveys typically target depths of 0–200 m, technological advancements have enabled deeper investigations, commonly referred to as Deep ERT. In this study, we explore the practical challenges and methodological improvements associated with Deep ERT, particularly when combined with induced polarization (IP) measurements. Rather than other electromagnetic methods, ERT offers a more straightforward framework for analysing IP effects, which can potentially correlate with the volume fraction of ore minerals. Nevertheless, deep IP investigations are often challenged by weak signal strength and various sources of electromagnetic interference. To address these challenges, we evaluated key strategies including survey planning, high-power current injection, unconventional electrode configurations and advanced signal processing techniques. The adoption of nodal geophysical recording systems eliminates the logistical constraints of cabled multi-electrode setups, improving flexibility and data acquisition efficiency. Additionally, continuous full time-series recording allows for enhanced noise filtering and signal stacking, ultimately increasing the signal-to-noise ratio and extending the effective exploration depth. We demonstrate this methodology through a comprehensive case study conducted at the Koillismaa Linear Intrusion Complex in Finland, where a 3-D Deep ERT-IP survey successfully delineated conductive and chargeable anomalies at depths exceeding 1.5 km. These anomalies closely align with independent gravity and borehole logging data, consistent with the mafic-ultramafic intrusion structures. Our results emphasize the importance of balancing data quality, survey efficiency and spatial resolution in survey design. This work not only provides a robust workflow for the implementation of Deep ERT-IP surveys but also represents the first documented successful acquisition of high-quality IP data at these substantial depths, significantly advancing the state of deep geoelectrical exploration.