Surface flow and internal structure of glacier-moraine complex (GMC) in northern Tien Shan

In the northern Tien Shan, numerous glacier–moraine complexes (GMCs) composed of debris and ice have developed in front of glacier termini in this semi-arid region, but the conditions under which internal ice is maintained remain unclear. In this study, we investigated GMCs in front of the Adygine Glacier, located in the Kyrgyz Range of the northern Tien Shan, to clarify the relationship between internal structure and surface morphology. Electrical resistivity tomography (ERT) surveys were conducted along 15 profiles with 48 electrodes at 5 m spacing in 2024 and 2025, and horizontal and vertical surface displacements were quantified using UAV-derived imagery.

The results showed that in the upper left bank, continuous flow from the glacier and connected subsurface ice were identified. In the middle left bank, although no surface flow was observed, continuous buried ice was present, accompanied by surface lowering. In the lower left bank, continuous buried ice connected to a tributary glacier was also detected. On the right bank, exposed bedrock was found in the upper part, where meltwater flowed over the surface without infiltration into debris. In the lower right bank, debris landforms were developed, but flow was weak and the frozen layer was discontinuous. These findings indicate that continuous ice supply from the glacier is crucial for maintaining subsurface ice within the GMC.