A multi-hazard map of China

Abstract

Since 1900, 35,000 natural hazard events have resulted in about eight million deaths worldwide, with about US$7 trillion in economic losses (Daniell et al., 2016). Conventional assessment focuses on individual hazards (see, e.g. Wei et al., 2015) but natural hazards do not exist in isolation. They may occur together, following a common cause (as in the case of heavy rain in northern Pakistan (2016) which produced both flood and landslide), or one hazard may induce another (as with the 2010 Tohoku Earthquake, Japan, which triggered a major Tsunami). The high frequency and intensity of such multiple hazards mean that attention should be given to multi-hazard assessment. China experiences many types of natural hazards and also has a highly uneven distribution of population and economic activity. It is therefore critical that its natural hazard risk managers better understand the spatial distribution of multi-hazard. Therefore, nine natural hazards (comprising flood, drought, heat wave, cold wave, earthquake, landslide, storm, wildfire and avalanche) were addressed to draw a multi-hazard distribution map of China (Figure 1). The number of hazard occurrences from 1981 to 2016 was selected as the hazard indicator. The multi-hazard index was the sum of each hazard indicator multiplied by its weight, calculated according to the average human life loss associated with this hazard. And the population of each province in 2016 was queried from the provincial statistical yearbook of China. In the map, the size of each polygon stands for the mass of population for each province in China, and the symbol (flood, drought, etc.) in each polygon represents the dominant hazard among these nine kinds of natural hazards within each province. The map shows that flood is the most dangerous hazard in most provinces, especially in the more densely populated area in east China. And less populated provinces in west China are influenced by earthquake most seriously, such as Tibet and Qinghai. In addition, densely populated provinces in southeast coastal areas are at highest multi-hazard index with storm as the dominant hazard, such as Guangdong, Zhejiang and Fujian. Understanding the