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Abstract. Permafrost degradation in Arctic lowlands is a critical geomorphic process, increasingly driven by climate warming and infrastructure development. This study applies an integrated geophysical and surveying approach – Electrical Resistivity Tomography (ERT), Ground Penetrating Radar (GPR), and thaw probing – to characterize near-surface permafrost variability across four land use types in Utqiaġvik, Alaska: gravel road, snow fence, residential building and undisturbed tundra. Results reveal pronounced heterogeneity in thaw depths (0.2 to >1 m) and ice content, shaped by both natural features such as ice wedges and frost heave and anthropogenic disturbances. Roads and snow fences altered surface drainage and snow accumulation, promoting differential thaw, deeper active layers, and localized ground deformation. Buildings in permafrost regions alter the local thermal regime through multiple interacting factors – for example, solar radiation, thermal leakage, snow cover dynamics, and surface disturbance – among others. ERT identified high-resistivity zones (>1,000 Ω·m) interpreted as ice-rich permafrost and low-resistivity features (<5 Ω·m) likely associated with cryopegs or thaw zones. GPR delineated subsurface stratigraphy and supported interpretation of ice-rich layers and permafrost features. These findings underscore the strong spatial coupling between surface infrastructure and subsurface thermal and hydrological regimes in ice-rich permafrost. Geophysical methods revealed subsurface features and thaw depth variations across different land use types in Utqiaġvik, highlighting how infrastructure alters permafrost conditions. These findings support localized assessment of ground stability in Arctic environments. 

Abstract The occurrence and magnitude of natural fossil methane (CH₄) emissions in the Arctic are poorly known. Emission of geologic CH₄, a potent greenhouse gas, originating beneath permafrost is of particular interest due to the potential for positive feedback to climate warming, whereby accelerated permafrost thaw releases permafrost‐trapped CH₄in a future warmer climate. The development of through‐going taliks in Arctic lakes overlying hydrocarbon reservoirs is one mechanism of releasing geologically sourced, subpermafrost CH₄. Here we use novel gas flux measurements, geophysical observations of the subsurface, shallow sediment coring, high‐resolution bathymetry measurements, and lake water chemistry measurements to produce a synoptic survey of the gas vent system in Esieh Lake, a northwest Alaska lake with exceedingly large geologic CH₄seep emissions. We find that microbially produced fossil CH₄is being vented though a narrow thaw conduit below Esieh Lake through pockmarks on the lake bottom. This is one of the highest flux geologic CH₄seep fields known in the terrestrial environment and potentially the highest flux single methane seep. The poleward retreat of continuous permafrost may have implications for more subcap CH₄release with increased permafrost thaw.