Cause Analysis of the Geological Hazards Induced by the 16 July 2018 Rainstorm in Beijing
The heavy rainfall occurred on 16 July 2018 in Beijing resulted in a series of serious hazards such as urban water logging and collapse hazards. Starting with the analysis on the features of rain regime and its associated geological hazard situations, this paper mainly analyzes and summarizes the forecast and verification on the early warning of meteorological geological hazards for this kind of extremely intense rainfall. Based on the detailed information of geological hazards, this study further analyzes the causes of geological hazards in Beijing by combining the characteristics of rainfall intensity, soil moisture and the runoff evolution (derived from the CREST model driven by quantitative precipitation estimation data). The results indicate that the northern and western parts of Beijing are areas characterized by the mid- and high-risk susceptibility degree, the accumulated area-rainfall beyond 50 mm is prone to result in the occurrence of geological hazards and the occurrence time is during the next 15 h after the high peak of precipitation. Based on the rainfall intensity and precipitation duration, the threshold of critical rainfall of geological hazards can be derived as a reference for geological hazard meteorological forecast in the area. The simulation of hydrological process elements such as runoff, depth of overland flow, and soil moisture of hydrological model also has a good guiding significance for early warning of meteorological geological hazards in Beijing.