Research Of Earthquake Information Extraction And Site Selection Based On VGI And Remote Sensing

The rapid acquisition and treatment of earthquake disaster is an important part of earthquake emergency,which can provide the decision-making basis for the rescue command.Furthermore,it can help us to comprehend the disaster,control public panic,reduce the damage of the earthquake.With the rapid development of communication technologies,smart terminals and social networking applications,people are increasingly involved in disaster response and information dissemination which produced a new data source—Volunteered Geographic Information(VGI).It provides a new opportunity for the extraction of earthquake disasters,such as OpenStreetMap(OSM),Twitter and Microblog.Besides,after a strong earthquake has occurred,a large number of secondary geological disasters such as landslides,mudslides and collapses have been activated which may last 5 to 20 years.The potential safety problems caused by the long-term of the human living environment,some areas are no longer suitable for residence or residential relocation,scientific location planning has become one of the urgent problems after the earthquake.With the rapid development of GIS and Remote Sensing technology,the ability of spatial data acquisition and analysis and processing has been greatly improved,playing an increasingly important role in site selection problem.In this paper,the research is based on Sina Weibo to extract earthquake damage information which takes 8.8 Jiuzhaigou Earthquake as an example.First,use web crawler technology to extract the original microblog data of four cities that may be affected by the earthquake.Second,establish the place name database to match address,remove the heavy text and classify the key words,in order to get the standardized location microblog data that contains time,place and type.Then,use Weighted Mean Center,Direction Distribution(Standard Deviation Ellipse),Inverse Distance Weighted(IDW)and other methods to analysis the spatial distribution of the microblog which in order to simulate the epicenter,intensity direction and influence range,compared with the official seismic intensity map.Finally,choose evaluation indexes that affect site selection in earthquake areas based on RS and OSM data sources.In addition,determine the weight and quantitative classification of the evaluation index,use GIS spatial superposition method to evaluate the suitability of degree VI and higher intensity,in order to provide decision support for the earthquake relocation site.The results are shown as follows:(1)The release of the earthquake microblog mainly focused on 24 hours after the earthquake,more precisely is 3 hours and 40 minutes after the earthquake.As time goes on,the number of microblog involved in earthquakes is gradually decreasing.We should focus on the acquisition of microblog in 40 minutes after the earthquake which can extract more useful information for disclosure and earthquake emergency rescue service.Besides,the main type of micro-blog are"Earthquake"and"People Responses",but"Housing Damage"and"Traffic Communication"are fewer that means the destruction of facilities caused by the earthquake is not particularly serious.(2)The seismic center simulated by the average center is close to the actual epicenter,the difference between the longitude and latitude is not more than 0.08degrees and 0.12 degrees.Using the direction distribution simulation of earthquake intensity greater similarity.With the increase of time,the X Y axis length,elasticity,area of standard deviation ellipse are decreased,elliptical direction are more obvious.Compared with the actual intensity area,the area and parameters are relatively close,but it deviates from the direction of the earthquake.Besides,use IDW to simulate the disaster surface,there is a great similarity in the area of the earthquake center.The county affected by moderate and above earthquakes are Jiuzhaigou County,Songpan County,Norgai County and Diebu County etc.(3)The suitable area showed zonal distribution is similar with the earthquake intensity and direction,mainly concentrated in the VI area and VII area near the crack line.The suitable area accounted for 9.96%,1821.35km~2 and 224 villages,but the unsuitable area is 17.47%,3195.36 km~2 and 3 villages.Combined with population density,10 settlements were selected in suitable areas.Besides,suggest the villages in the unsuitable area ecologically immigration,strengthening environmental protection and ecological restoration.Villages in the basic suitable area will be relocated to suitable areas in batches according to the degree of earthquake influence.Moreover,the function of township needs to be perfected and the living environment needs to be promoted.