At 2:03 a.m. on July 19, 2020, landslide alarms in the Xishan residential area—a high-risk zone in Huayue Community, Maojian District, Shiyan City—repeatedly sounded evacuation alerts. Startled residents immediately followed instructions and evacuated their homes. At 2:26 a.m., a small-scale rock collapse occurred, with approximately 3 cubic meters of debris breaking loose.
Though minor, this incident demonstrated the high sensitivity of the "Disaster Whistle" monitoring system, which detected pre-collapse deformations and issued timely warnings. The technology proves even more critical in forecasting larger, more hazardous geological events, effectively safeguarding lives and property. Thanks to the "Stability Evaluation Model and Early Warning System for Slope Failures," two households (seven residents) were successfully evacuated.
Huayue Community is one of two pilot zones in Shiyan’s "Disaster Whistle" program for specialized geological hazard monitoring. Four at-risk sites in the area were equipped with cost-effective monitoring devices in May 2020, including the Xishan slope where this collapse occurred.
The site was installed with 10 microelectromechanical tilt sensors. Data revealed that between 1:58 a.m. and 2:03 a.m., sensors #5 and #6 recorded a sudden spike in rock inclination along the X-axis (jumping from ~2.0° to 25.9°), triggering the alarm. By 2:26 a.m., the cumulative tilt at sensor #5 reached 66.2994°, leading to the rockfall. Post-collapse, sensor #6 remains in a triggered state, while neighboring sensors showed significant anomalies before and after the event.
