Hydrogeomorphology of Lava Rise Pits in The Laki Lava Field, Southeast Iceland

Lava Rise Pits (LRPs) are found within the Laki lava field in Southern Iceland. LRPs naturally occur in pahoehoe lava flows and form when the flow in lava tubes ceases and collapses. The goal of this study was to better understand the hydrogeomorphology of LRPs during the Fall-winter season. Three LRPs were selected, and a range of sensors and measurements monitored thermal and soil moisture (SM) regimes, precipitation, and vegetation and soils surveys.

Thermal regimes were primarily impacted by depth, pit openness, ground temperatures (GTs) and air temperature (AT). LRPs more open and exposed to the atmosphere, their near surface above-ground, and GTs mimicked ATs. Precipitation was the most important source of water, with overland flow, and groundwater potentially having a significant role within the LRPs. When GTs were below 0°C, SM levels were low and once GTs rose, snow and ice melt increased SM, linking SM and GT conditions.