Thermo-hydrological modeling of ground freezing and its relations to occurrence of frost quakes in northern Finland

In the northern periphery, acceleration of hydrological cycle due to global warming include an increase in frequency and intensity of extreme events. Among the consequences of these extreme events in wintertime one can observe an increase of damage to the built environment and natural landscape in the form of fractures. These result from changes in the rain/snow relationship, snowmelt and freeze-thaw cycles. Sometimes these fractures initiate and develop in a manner accompanied by a sudden release of (seismic) energy, commonly known as frost quakes.

Our objective is to study soil freezing, cryosuction phenomena and its relation to occurrence of frost quakes in northern periphery in Finland in the city of Sodankylä. We build a 1D hydrological model that accounts for snow accumulation and melt and heat transfer into to soil and liquid/gas/ice content in subsurface. The hydrological 1D model was calibrated against the measured soil water content and temperature at five different depths in soil during the wintertime 2023/2024. The aim of this study is to understand the ice lens formation, cryosuction process, change in the air and the soil temperature and how these are connected to frost quake occurrence. During the winter 2023/2024 several frost quakes occurred in Sodankylä that are related to rapid change in air temperature, soil temperature and change in cryosuction pressure.