<p>Debris avalanches enhance their destructiveness by eroding and entraining basal material, leading to increased flow volume and improved mobility. The impact and shear stresses exerted by debris avalanche on the underlying substrate result in stress fluctuations and alter the seismic signals. To investigate debris avalanche dynamics, flume experiments were conducted to examine how erodible bed length, inclination angle, and entry angle affect the movement and seismic signatures. The experimental results show that longer erodible disturbance zones lead to lower peak values in basal normal and shear stress, while the stress duration becomes shorter accordingly and the energy dissipation increases. Seismic analysis further indicates that impact intensity and peak power decrease as the disturbance length increases, and a larger entry angle enhances momentum transfer and tends to trigger the entrainment process earlier. Further, layer by layer staining of the erodible material reveals material exchange and mixing as the debris avalanche passes through the disturbance zone, indicating nonlocal rheological behavior of granular motion. The entrained fine basal particles accumulate near the base forming a lubrication layer, which reduces the basal friction coefficient and promotes flow mobility in the later stage. This finding indicates that the erosive disturbance zone has a significant influence on basal stress fluctuations and acceleration signals generated during debris avalanche motion.</p>