Time-Lapse Three-Dimensional TEM Imaging and Damage Evolution of Hydraulic Fracturing in Landslide Fracture Zones

Landslide fracture zones play a critical role in slope instability, yet their hydraulic fracturing processes remain difficult to monitor using conventional geophysical methods. This study proposes a time‐lapse three‐dimensional transient electromagnetic (TEM) imaging approach to characterize fracture damage evolution in the Xiaolongdong–Xiahaizi landslide, Zhaotong City, China. Repeated TEM observations, integrated with GNSS displacement monitoring and environmental measurements, were used to reconstruct dynamic resistivity fields through three‐dimensional inversion. The method achieved localization accuracies better than 1 m horizontally and 2 m vertically and detected water‐filled fractures wider than 0.3 mm. Distinct resistivity precursor anomalies, characterized by a 3%–8% increase followed by a rapid decrease, occurred 2–5 min before fracture propagation. During hydraulic fracturing, resistivity decreased from 30–50 Ω·m to 8–15 Ω·m, reflecting progressive fracture connectivity. Rainy‐season permeability coefficients reached 10⁻⁴–10⁻³ m/s, one to two orders of magnitude higher than those during the dry season. Freeze–thaw processes and rainfall infiltration jointly contributed 25%–35% of slope displacement. The proposed framework provides quantitative visualization of fracture evolution and effective geophysical constraints for landslide stability assessment and early warning.