利用居民地建筑物数据和高分遥感影像评估地震烈度的方法初探

A PRELIMINARY STUDY ON THE METHOD OF SEISMIC INTENSITY ASSESSMENT BASED ON RESIDENTIAL BUILDING DATA AND HIGH RESOLUTION REMOTE SENSING IMAGES

地震发生后,政府和社会对地震烈度评定工作的时效性要求越来越高,而遥感作为地震灾情获取的重要手段之一,在地震应急救援工作中发挥着越来越重要的作用。文中在前人研究的基础上,提出了一种利用遥感影像结合居民地建筑数据评估地震烈度的方法模型:在已知居民地建筑物数据的情况下,利用群体震害预测方法,构建居民地房屋倒塌率与地震烈度之间的关系模型;震后利用高分辨率遥感影像解译居民地房屋的倒塌率,并与倒塌率预测模型进行比对,反推该居民地遭遇的地震烈度。利用本方法对玉树县城内相邻但破坏情况相差巨大的2个街区进行了烈度计算,计算结果与现场科考结果一致。经验证,在利用遥感手段评估地震烈度时,本方法能有效避免由建筑抗震性能差异造成的影响,可较准确地评估地震烈度,在地震应急工作中具有一定的应用价值。

After destructive earthquakes,the assessment result of seismic intensity is an important decision-making basis for emergency rescue,recovery and reconstruction.This job requires higher timeliness by government and society.Because remote sensing technology is not affected by the terrible traffic conditions on the ground after the earthquake,large-scale seismic damage information in the earthquake area can be collected in a short time by the remote sensing image.The remote sensing technique plays a more and more important role in rapid acquisition of seismic damage information,emergency rescue decision-making,seismic intensity assessment and other work.On the basis of previous studies,this paper proposes a new method to assess seismic intensity by using remote sensing image,i.e.to interpret the building collapse rate of a residential quarter after an earthquake by high-resolution remote sensing images.If there already are detailed building data and building structure vulnerability matrix data of a residential area,we can calculate the building collapse rate under any intensity values in this residential area by using the theory of earthquake damage prediction.Assuming that the building collapse rate interpreted by remote sensing is equal to the building collapse rate predicted by using the existing data,it will be easy to calculate the actual seismic intensity of the residential area in this earthquake event.Based on this idea,according to the relevant standard specifications issued by China Earthquake Administration,this paper puts forward some functional models,such as the calculation model of building collapse rate based on remote sensing,the data matrix model of residential building structure,the prediction function matrix model of residential building collapse rate and the prediction model of residential building collapse rate.A formula for calculating seismic intensity by using remote sensing interpretation of collapse rate is also proposed.To test and verify the proposed method,this paper takes two neighboring blocks of Jiegu Town after the Yushu M7.1 earthquake in Qinghai Province as an example.The building structure matrix of the study block was constructed by using pre-earthquake 0.6m resolution satellite remote sensing image(QuickBird,acquired on November 6,2004),post-earthquake 0.2m aerial remote sensing image(acquired by National Bureau of Surveying and Mapping,April 15,2010)and some field investigation data.The building collapse rate in the two blocks was calculated by using the interpretation results of seismic damage from the Remote Sensing Technology Coordinating Group of China Seismological Bureau.The seismic damage matrix of building structures in Yushu area is constructed by using the abundant scientific data of the scientific investigation team of the project“Comprehensive Scientific Investigation of the Yushu M7.1 Earthquake in Qinghai Province”of China Seismological Bureau.On this basis,the collapse rate prediction function of different structures in Yushu area is constructed.According to the prediction function of collapse rate and the building structure matrix of the two blocks,the building collapse rate under different intensity values is predicted,and the curve of intensity-collapse rate function is drawn.By comparing the building collapse rate interpreted by remote sensing and the intensity-collapse rate function curve of this two blocks,the seismic intensity of both blocks are calculated to be the same value:Ⅸdegree,which is consistent with the results of the field scientific investigation of the earthquake.The validation shows that the method proposed in this paper can effectively avoid the influence caused by the difference of seismic performance of buildings and accurately evaluate seismic intensity when using remote sensing technique.The method has certain application value for earthquake emergency work.