Geophysical Assessment of Electrical resistivity of frozen ground Distributions in Mountain Road Areas of Tierra del Fuego, Chilean Patagonia.

The study aims to assess the distribution of frozen ground in mountain road areas of Tierra del Fuego, Chilean Patagonia, using geophysical methods such as electrical resistivity tomography (ERT). The research focuses on the Y-85 road, which needs to gain enough altitude to avoid wetlands and cross the treeline. The presence of active periglacial features above 650 m a.s.l. Suggesting the possible presence of permafrost in the area the study employed a quasi-3D ERT survey using a Syscal-Pro device with 24 electrodes spaced 1.5 meters apart. The inversion process was performed using the open-source software ResIPy, with the expected data error evaluated through reciprocal checks. The results of the study show that the resistivities in the North and Middle sites are significantly higher, ranging from 40 to 100 kΩm at relatively shallow depths of less than 2 meters, compared to the South site, which has about one log order lower resistivities. These findings indicate the presence of a shallow discontinuous frozen subsoil in the North and Middle sites, which is likely composed of permafrost. The higher resistivities in the North and Middle sites suggest the presence of a frozen subsoil, which is characteristic of permafrost, while the lower resistivity in the South site suggest the absence of permafrost. The results of this study provide valuable information for the construction of the Y-85 road, which is expected to face various mechanical stress and risks related to periglacial processes once it crosses the treeline at 650 m a.s.l. The identification of the presence and distribution of frozen ground in the area is crucial for understanding the geological and environmental conditions and for the planning and construction of the road infrastructure.

The study aims to assess the distribution of frozen ground in mountain road areas of Tierra del Fuego, Chilean Patagonia, using geophysical methods such as electrical resistivity tomography (ERT). The research focuses on the Y-85 road, which needs to gain enough altitude to avoid wetlands and cross the treeline. The presence of active periglacial features above 650 m a.s.l. Suggesting the possible presence of permafrost in the area the study employed a quasi-3D ERT survey using a Syscal-Pro device with 24 electrodes spaced 1.5 meters apart. The inversion process was performed using the open-source software ResIPy, with the expected data error evaluated through reciprocal checks. The results of the study show that the resistivities in the North and Middle sites are significantly higher, ranging from 40 to 100 kΩm at relatively shallow depths of less than 2 meters, compared to the South site, which has about one log order lower resistivities. These findings indicate the presence of a shallow discontinuous frozen subsoil in the North and Middle sites, which is likely composed of permafrost. The higher resistivities in the North and Middle sites suggest the presence of a frozen subsoil, which is characteristic of permafrost, while the lower resistivities in the South site suggest the absence of permafrost. The results of this study provide valuable information for the construction of the Y-85 road, which is expected to face various mechanical stress and risks related to periglacial processes once it crosses the treeline at 650 m a.s.l. The identification of the presence and distribution of frozen ground in the area is crucial for understanding the geological and environmental conditions and for the planning and construction of the road infrastructure.