Instrumentation of the Permafrost Boreholes at Adlersruhe (3,454 m) and First Measurement Results

Following the successful drilling of two new 20 m deep permafrost boreholes at the Erzherzog Johann Hut (“Adlersruhe”), the boreholes were equipped with temperature sensor chains by GEORESEARCH and the State of Salzburg in October 2025.

Since then, rock temperatures have been continuously monitored at depths ranging from 0.1 m to 20 m with an accuracy of ±0.05 °C. Measurements are carried out in both the northern and southern boreholes. Initial results show a pronounced autumn cooling signal in the near-surface zone (0.1–1 m) caused by declining air temperatures. At depths below 10 m, however, relatively stable rock temperatures were recorded: approximately −3.4 °C in the northern borehole and −2.5 °C in the southern borehole. The nearly 1 °C higher rock temperatures measured in the southern borehole are most likely related to its immediate proximity to the highly radiation-exposed south face.