Objective The geological disasters in mountainous towns of loess areas have the characteristics of many geological disaster points and wide areas. The current disaster management mode is mainly based on the traditional hazard point control, but most of the geological disasters in recent years are outside the scope of control. Therefore, the existing risk management and control system need to be innovated and improved.
Methods In response to the complexity of loess geological disaster risk management, an exploratory methodology has been devised for a geological disaster refined risk “double−control of point and zone” system applicable to mountain towns in loess regions. Firstly, for the “point control” link, the stability, hazard and risk assessment of geological disaster hazard points are carried out on the basis of field investigation. Secondly, for the “zone control” link, geological background factors and geological disaster triggering factors suitable for loess regions are selected based on slope units, and statistical models such as information method are used to evaluate the susceptibility and hazard of geological disaster, and the risk level of slope unit is evaluated considering the vulnerability of disaster bearing body. Finally, a geological disaster risk “double−control of point and zone” map is formed based on the administrative village unit, and an eight−level rainfall warning division method is proposed for loess regions, along with corresponding defense and response measures.
Results Taking the main urban area of Mizhi County in Yulin City, Shaanxi Province as a case study, a double control management system for “hazard points and risk areas” of geological disaster has been established. The study findings show that the area is divided into 57 administrative village units, with 1 extremely high risk hazard points, 14 high risk hazard points, 1 medium risk hazard point, 5 low risk hazard points, 29 extremely high risk slopes (accounting for 0.45% of the area), 111 high risk slopes (accounting for 2.19% of the area), 804 medium risk slopes (accounting for 19.35% of the area), and 3596 low risk slopes (accounting for 78.01% of the area). Based on this, a corresponding geological disaster risk “double−control of point and zone” map is drawn, providing scientific basis for local governments to prevent and reduce disasters.
Conclusions This study provides a new insight for geological disaster risk management in loess regions, but it is still at an exploratory stage. In the future, we need to further deepen the integration of technology and management, continuously improve the geological disaster social service capacity and level.
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