Introduction

China locates in the southeast of Eurasia and between the two major seismic belts in the world, the Eurasian seismic belt and the circum-Pacific seismic belt (Liu et al. 2014; Gorum et al. 2011; Wu et al. 2017). Due to the compression of the Pacific plate, the Indian plate and the Philippines plate, the geological structures are complicated, while the seismic fault zones are well developed in China. Consequently, it is a country with severe earthquake disasters, which are characterized by high frequency, heavy intensity, shallow epicenter and extensive distribution and so on (Cui et al. 2017; Li et al. 2015; Lai et al. 2015, 2016b, d). Compared with the global large seismic activities, the seismicity with MS 7.0 or above in China and its neighboring regions has characteristics of quasi-synchronous evolutions (Li et al. 2017; Lai et al. 2017). Since 2008, continuous earthquakes occurred, which indicated that the mainland China has entered a newly active period of seismic activities (An et al. 2010; Lai et al. 2018). China’s land area accounts for 7% of the global land area, while the population accounts for about 20% of the total world population. However, China has to bear about 33% of the successive earthquakes occurred in the world, resulting in the number of people killed by these earthquakes reached more than 50% of all global earthquake death (Qiu et al. 2017, 2018a, b; Zhou et al. 2017). China has suffered serious damage and losses in numerous disasters. In China, the potential seismic activities are mainly distributed on 23 seismic belts in four seismic regions. The four seismic regions are: 1 southeastern Taiwan and coastal Fujian Province; 2 along Taihang Mountains in North China; 3 the Tibetan Plateau and its marginal Sichuan Province in southwest China; 4 Xinjiang, Gansu and Ningxia provinces in western China (Fig. 1) (Cui et al. 2011; Lai et al. 2016a, c; Zhao and Xu 2014). There is a dense seismic belt, called ‘‘north–south seismic belt,’’ with an approximate north–south orientation that runs through the mainland China, originating from Ningxia Province, throughout eastern Gansu and Qinghai provinces, ending in Yunnan and Sichuan provinces. Historically, in this active belt, a series of destructive disasters emerge, including the most devastating earthquakes, such as the 2008 Wenchuan earthquake and 2010 Yushu earthquake (Zhang et al. 2010; Lai et al. 2014; Zhao and Xu 2014). The Eurasian plate is constantly squeezed by the Indian plate, causing a subduction of the Indian plate to northern region and thus making these belts active (Fig. 1).