Hazard Assessment Of Landslide And Collapse Induced By Volcanic Eruption In Changbai Mountains

The Tianchi volcano is located in the southeast of Jilin Province and this area is a very important part in Changjitu Development Zone. Tianchi volcano in Changbai Mountain is an important tourist attraction in China that attracted a large number of tourist population every year. The seismic force that generated by volcanic earthquake will lead to a large number of landslides and collapses disaster in unstable slope if volcanic eruption happen. These disasters would cause a lot of loss of life and property and affect the development of the region. The monitoring results of Tianchi volcano in Changbai Mountains showed that the magnitude of volcanic earthquake、ground deformation、 the frequency of earthquake occurrence and the greenhouse gas emissions are all showed a clear upward tread in 2002-2005.The frequency of volcanic earthquake even reached more than 1200 times a year. Besides,The latest monitoring results show that the temperature of Julong Spring had increased by 3℃ than it was in previous years and the elevation of the volcanic cone was reduced by 12.72 mm instead of up 4mm like before. The Monitoring results showed that the Tianchi Volcano had the probability of resurrection.In this paper, the geological hazards investigation and division report of each county and city in Changbai Mountain area of Jilin province were consulted. The number of collapse, landslide and unstable slope of each county and city were collected. There are 11 evaluation indexes which contain slope、exposure、annual rainfall and so on were being selected and sensitive evaluation of landslide was being conducted by rough set theory. The evaluation results showed that the slope and the exposure were the main factors that controlled the development of landslide and collapse disaster and get the evaluation results of susceptibility. The most important influence that the effect of Tianchi volcano eruption on the collapse and landslide disaster is the earthquake force. In this paper, two methods were used to evaluate the landslide hazards in Changbai Mountain area.(1) The number of collapses and landslides in different intensity areas showed a significant increase when the earthquake intensity reached and exceeded VI. Therefore, the seismic intensity value of VI was used as the threshold value of earthquake triggered landslide hazard. The Formula about the Relationship between magnitude and annual probability was got based on the historical data of Tianchi volcano eruption. According to the formula, the probability of earthquake intensity greater than VI corresponding to different epicenter distance is calculated. Transcendental probability partition graph was being calculated on the ArcGIS platform and the magnitude of the probability value reflects the strength of the volcanic action. The result of the multiplication of the susceptibility zoning map and the probability of exceeding probability zoning map was used as the final risk zoning map.(2) Newmark cumulative displacement model was widely used in earthquake triggered landslide hazard assessment of landslide hazard. Newmark cumulative displacement model was widely used in earthquake triggered landslide hazard assessment of landslide hazard. The Displacement model that Jibson put forward in 1992 was considered to be the most suitable for the study area after a selection. The calculation results of the cumulative displacement were used as the basis for the division of danger.By comparison, we can know that the results obtained by the two methods were basically consistent. However, the above method involved a lot of image processing and formula calculation, the process was very complex. Two model about the above two methods were constructed by Model Builder in ArcGIS and reduce the error that may caused by human factors, and have the characteristics of repetitive operation.