<p>The morphometric characteristics of a watershed play a crucial role in debris-flow initiation and provide key insights into the required triggering rainfall intensity. Despite this significance, limited research has examined how these topographic attributes influence rainfall thresholds. Focusing on the Wenchuan earthquake zone, this study employs statistical methods to analyze the relationship between watershed morphometry-including area, relief, relief ratio, channel gradient, and Melton index-and debris-flow triggering rainfall intensity. Results reveal that susceptible basins in this region exhibit greater areal extent and longitudinal dimensions compared to global counterparts, yet display lower Melton indices and gentler channel slopes. These findings imply that seismic activity modified debris-flow initiation conditions, as abundant loose material now requires reduced gravitational potential for mobilization. Watershed shape characteristics (catchment area) demonstrate a weak Gaussian correlation with triggering rainfall intensity, whereas slope-related features (channel gradient and Melton index) exhibit an inverse logarithmic relationship. Of all parameters analyzed, channel gradient and Melton index show the strongest association with triggering rainfall intensity. This research advances our comprehension of debris-flow triggering rainfall intensity and supports more accurate susceptibility evaluations in earthquake-affected regions.</p>