Study On The Risk Evaluation Of Earthquake Geological Hazards In Songpinggou Scenic Area And Its Application

The Songpinggou area was affected by multiple earthquakes.In particular,the 1933 Diexi earthquake affected the topography and geologic hazards of the Songpinggou area,resulting in the formation of more than a dozen earthquake-swept lakes,thus providing a wealth of travel resources.On June 24,2017,a landslide took place in Xinmo Village,Diexi Town,Maoxian County,Sichuan Province.The high landslide destroyed the village at the foot of the slope.It caused major economic losses and casualties,and led directly to shut down the Dianxi-Songpinggou Scenic Area.Songpinggou Scenic Area is the first provincial-level scenic spot on the western line of Jiuhuan Road.It is one of the most intact earthquake damaged sites in the world,a famous red-leaf viewing spot in China and a national AAAA-level scenic spot.The beautiful scenery of the Songpinggou scenic spot was born due to the earthquake.At the same time,there were also various geological disasters accompanied by the earthquake.Combined with the complex geological structure of the region,the research of geological planning of the area and the protection of the urban geological environment based on the geological environment is very necessary and urgent.In view of this,this study takes seismic and geologic hazards in the Songpinggou area as the research object,aims at risk assessment at different scales,and obeys the thoughts and principles of engineering geology,statistics,and human geography,through field surveys and remote sensing interpretations,data collection and consolidation,numerical simulation and other methods combined to achieve seismic damage risk assessment of different degrees of damage.The main results include the following aspects:(1)Geoenvironmental background investigation and analysis of earthquake geological disasters in Songpinggou Scenic AreaIn this paper,the geological environment of the study area such as natural geography,meteorology and hydrology,stratum lithology and other geological data collection and collation,on-site investigation,identified the geological environment background of the earthquake geological disasters in the study area.In particular,the development of the Songpinggou fault,the most important seismic structure in the study area,was determined.(2)Study on the development and distribution of earthquake geological disasters in Songpinggou Scenic AreaAccording to the site survey,according to the degree of damage caused by the earthquake to the geological body,the geological bodies in the study area are divided into three categories: the first category is the accumulation of geological disasters(include landslides and collapses),the second category is potential disasters(unstable slope).and category 3 is a geological body that has not been deformed by the terrain or has not been investigated for deformation.This paper statistically analyzes the characteristics and regularities of the earthquake geological disasters in the study area in terms of disaster type,plane distribution,and spatial distribution.The development and distribution of earthquake geological disasters are strongly affected by the Songpinggou fault.The development and distribution of the disasters are significantly affected by the fault's footwall effect and distance effect.(3)Risk assessment of single earthquake geological disasterThe results of the risk assessment of the first two types of disasters show that there are five low-risk(I)disaster sites in the monolithic earthquake geological disasters in the study area,accounting for 25% of the total,five moderate-risk(II),accounting for 25%,9 high-risk(III),accounting for 45%,and 1 very high risk(IV),accounting for 5%.The risk level is a comprehensive manifestation of the possibility of geological disasters and the magnitude of losses incurred after the occurrence of geological disasters.It should be closely monitored for disaster sites with a risk level of Grade III or above to prevent the occurrence and expansion of disaster losses.(4)Regional geological disaster risk assessmentThe area of medium-and low-risk areas in the study area accounted for 91% of total,and high and very high risk areas accounted for 9%.The large area of the study area belongs to the low risk area,and followed by the medium risk area.The medium-risk areas are distributed along the main channel and the S448 line,interspersed with high and extremely high-risk areas,and the high-risk areas mainly occur from the begaining of Songpinggou to Huazilin section,and from the Diaogong village to the Moshi village section.(5)Evaluation of openability of scenic spots based on risk assessment of geological disasters and suggestionsFor the scenic spots that have already been built and put into operation,regional geological disasters risk is generally high.If no corresponding risk control measures are taken,scenic spots cannot be opened.For the scenic spot to be developed and constructed,the development of the Songpinggou scenic spot shall be considered on the basis of strict geological disaster research.For the formed residential settlements and residential areas,the risk level in some areas is relatively high.Regional geological deformation should be closely monitored and immigration should be considered to prevent major catastrophic accidents.