| Wenchuan earthquake happened in Sichuan province in2008brought a lager number of secondary geo-hazards. These disasters not only caused huge losses to people’s lives and property, but also planted the great hidden danger for future social economic development. Secondary geo-hazards have certain hysteresis, and have an active phase in the period of time after earthquake. The future development trend of secondary geo-hazards is one of the problems that post-disaster reconstruction will face. Therefore, researches of the secondary geo-hazards features, situation of disaster, risk and the development trend could provide scientific basis for reducing the secondary geo-hazards losses and prevention of secondary geological disasters.This paper selects a research area which includes the Wudu, Wenxian and Kangxian of Gansu. Based on the previous research and the field investigation after the earthquake, earthquake secondary geo-hazard materials were detailed analyzed. According to the actual situation of the study area, the relationship between the occurrence of secondary geo-hazards and affecting factors is analyzed using GIS technology. According to the distribution, type and scale of secondary geo-hazards, we analyzed situation and risk of secondary geological disasters, which include injured population, death population, direct economic losses and threaten population. Through statistical analysis the geological disasters before earthquakes in recent years and potential secondary geo-hazards, and combination with history secondary geo-hazards research, we forecast the future development trend of secondary geo-hazards. The results showed that the type of secondary geo-hazards is primarily collapses, landslides and ground fissures, which mainly distribute in roads, river and the adjacent area of towns and villages. Secondary geo-hazard scales are mainly middle-size and small-size. Hazard scale becomes smaller with the distance increasing away from the epicenter. Researches of the influence factors show that earthquake secondary geo-hazards easily occur in the areas of weak strata, rock broken, valleys development, large gradient, heavy concentration precipitation and it is also easily happened in mountainous climate and human activities effected large areas. Area of great situation disasters and high risk mainly distribute in Wudu and Wenxian, which scale became smaller with the increase of the epicentral distance. These situation disasters and risk mainly concentrate on1kilometer and2kilometers range of towns and villages. In the range of earthquake effect, enduring the influence of various factors, secondary geo-hazards will continue to happen in the future for a very long time, and have direct relation with precipitation and potential secondary geo-hazards. |
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