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- Title
Mapping Permafrost Variability and Degradation Using Seismic Surface Waves, Electrical Resistivity, and Temperature Sensing: A Case Study in Arctic Alaska.
- Authors
Tourei, Ahmad; Ji, Xiaohang; Rocha dos Santos, Gabriel; Czarny, Rafal; Rybakov, Sergei; Wang, Ziyi; Hallissey, Matthew; Martin, Eileen R.; Xiao, Ming; Zhu, Tieyuan; Nicolsky, Dmitry; Jensen, Anne
- Abstract
Subsurface processes significantly influence surface dynamics in permafrost regions, necessitating utilizing diverse geophysical methods to reliably constrain permafrost characteristics. This research uses multiple geophysical techniques to explore the spatial variability of permafrost in undisturbed tundra and its degradation in disturbed tundra in Utqiaġvik, Alaska. Here, we integrate multiple quantitative techniques, including multichannel analysis of surface waves (MASW), electrical resistivity tomography (ERT), and ground temperature sensing, to study heterogeneity in permafrost's geophysical characteristics. MASW results reveal active layer shear wave velocities (Vs) between 240 and 370 m/s, and permafrost Vs between 450 and 1,700 m/s, typically showing a low‐high‐low velocity pattern. Additionally, we find an inverse relationship between in situ Vs and ground temperature measurements. The Vs profiles along with electrical resistivity profiles reveal cryostructures such as cryopeg and ice‐rich zones in the permafrost layer. The integrated results of MASW and ERT provide valuable information for characterizing permafrost heterogeneity and cryostructure. Corroboration of these geophysical observations with permafrost core samples' stratigraphies and salinity measurements further validates these findings. This combination of geophysical and temperature sensing methods along with permafrost core sampling confirms a robust approach for assessing permafrost's spatial variability in coastal environments. Our results also indicate that civil infrastructure systems such as gravel roads and pile foundations affect permafrost by thickening the active layer, lowering the Vs, and reducing heterogeneity. We show how the resulting Vs profiles can be used to estimate key parameters for designing buildings in permafrost regions and maintaining existing infrastructure in polar regions. Plain Language Summary: This study descriptively examines permafrost variability across a range of disturbed and undisturbed locations in Utqiaġvik (formerly known as Barrow), Alaska, using a variety of geophysical techniques including seismic and electrical methods, complemented by ground temperature sensing. Geophysical profiles and maps were generated and used to identify permafrost features such as ice‐rich and ice‐poor zones. The study found that seismic shear wave velocity is influenced by ice content and can distinguish between the active layer and permafrost. We reinforced our geophysical observations with layering and salinity analyses from core samples, confirming the effectiveness of our combined approach in assessing permafrost variability in coastal regions. The research results regarding permafrost thickness reveal the impact of civil infrastructure, finding that buildings and roads can cause permafrost to degrade. Key Points: Shear wave velocity profiles can determine permafrost heterogeneity. Active layer Vs range: 240–370 m/s, permafrost Vs range: 450–1,700 m/sCombining geophysical and temperature sensing methods provides a robust approach for assessing the spatial variability of permafrostCivil infrastructure impacts permafrost, causing thicker active layers, lower Vs, and less heterogeneity
- Subjects
ALASKA; TUNDRAS; SEISMIC waves; ELECTRICAL resistivity; PERMAFROST; SEISMIC wave velocity; BUILDING foundations
- Publication
Journal of Geophysical Research. Earth Surface, 2024, Vol 129, Issue 3, p1
- ISSN
2169-9003
- Publication type
Article
- DOI
10.1029/2023JF007352