Japan Geoscience Union Meeting 2025

Presentation information

[E] Poster

H (Human Geosciences ) » H-DS Disaster geosciences

[H-DS07] Landslides and related phenomena

Fri. May 30, 2025 5:15 PM - 7:15 PM Poster Hall (Exhibition Hall 7&8, Makuhari Messe)

convener:Gonghui Wang(Disaster Prevention Research Institute, Kyoto University), Hitoshi SAITO(Graduate School of Environmental Studies, Nagoya University), Masahiro Chigira(Fukada Geological Institute), Fumitoshi Imaizumi(Faculty of Agriculture, Shizuoka University)

5:15 PM - 7:15 PM

[HDS07-P01] Tracking Landslide Motion: A Kinematic Approach Using Velocity-Acceleration Phase Plane

★Invited Papers

*Takashi Okamoto1, Issei Doi2, Sumio Matsuura2, Hikaru Osawa3, Shinichi Tosa4, Tatsuya Shibasaki4 (1.Tohoku Research Center, Forestry and Forest Products Research Institute, 2.Disaster Prevention Research Institute, Kyoto University, 3.Forestry and Forest Products Research Institute, 4.Japan Conservation Engineers & Co., Ltd.)

Keywords:Landslides, Acceleration, Phase plane, Kinematic analysis

Landslide displacement is a critical factor in establishing early warning systems and evaluating the effectiveness of mitigation measures. Conventionally, landslide activity has been assessed based on time-series displacement data, which provide limited insights into landslide dynamics. This study proposes a kinematic approach to visualize and evaluate landslide movement by analyzing the relationship between velocity and acceleration through a phase plane representation.
Three landslide monitoring sites were analyzed: (A) Shirishizu and (B) Senposhi in Hokkaido Prefecture, and (C) Busuno in Niigata Prefecture. Sites (A) and (B) experienced rapid movements within 24 hours, with high-precision data (+/- 0.1 mm, 5-minute intervals), while site (C) exhibited slow movements over several years with lower data precision (+/- 0.3 mm, daily intervals). Velocity and acceleration were derived from displacement data and plotted in a velocity-acceleration phase plane to track motion trajectories over time.
The results indicate that, for all sites, the trajectories exhibit a clockwise pattern relative to the zero-acceleration axis, reflecting the transition from movement initiation to cessation. In the phase plane, positive acceleration phases signify a state of increasing movement where driving forces exceed resisting forces, indicating high landslide risk independent of velocity. Conversely, negative acceleration phases represent decelerating motion, suggesting a reduced risk. When trajectories remain on the zero-acceleration axis, landslides move at a constant velocity, indicating that the driving and resisting forces are in equilibrium. This equilibrium represents a quasi-steady state.
The quality of observational data significantly influenced the interpretation of the motion characteristics. Higher-precision and short-interval data from sites (A) and (B) provided smooth and clear trajectories, facilitating detailed assessments of landslide motion. In contrast, the lower-precision and long-interval data from site (C) resulted in complex trajectories with abrupt changes, yet offered potential for long-term anomaly detection in landslide risk management.

This work was supported by JSPS KAKENHI Grant Numbers JP20H01984,JP22H01309,JP23K22580.