The earthquake secondary geological hazards are referred to those geological hazards due to earthquakes.They can be classified mainly into land collapse and landslide

together with subsidence

ground fissure and sand liquefaction

etc.The destructive effect and damage level of earthquakes could be exacerbated by the secondary geological hazards

which poses great difficulty

in turn

for the rescue and relief work

and the post-disaster reconstruction.Generally

earthquakes with magnitude over 5.0 and intensity beyond Ⅵ would result in geological hazards at certain degrees

the higher the magnitude and the intensity were

the more serious would be the secondary geological hazards.Based on the conditions and serious extents of the earthquake secondary geological hazards in history

the risk levels have been assessed in this paper at prefectural（city

region

union） units: The areas with high and moderate levels of risk are mainly distributed in the region of Shanxi-Gansu-Ningxia-Sichuan-Chongqing-Yunnan-Tibet

being located in the central part of China and forming a nearly NNE-striking zone of high risk levels

and the most of other areas are of low levels of risk.