Study On The Death Assessment Model Of Regional Earthquake Disasters Based On Magnitude

With frequent seismic activity,shallow seismic sources,high seismic intensity and wide distribution,earthquakes in China have caused serious economic losses and a large number of casualties.After the earthquake,the situation of the disaster area cannot be obtained within a short period of time.Determining the number of casualties is of great significance to the classification of earthquake disaster levels and earthquake disaster response levels,as well as the allocation of rescue materials and rescue forces.This paper summarizes the characteristics of earthquake hazards,the pattern of earthquake deaths and the characteristics of secondary geological hazards based on earthquake data in China's mainland from 1966 to 2019.The results show that:(1)the distribution of seismic hazards varies relatively widely from region to region,about half of earthquakes cause disasters each year,and the number of seismic hazards is relatively constant,the probability of an earthquake causing a hazard event increases exponentially with increasing magnitude.(2)Earthquake fatalities have significant regional variation,reaching a peak in fatalities approximately every 30 years,Earthquakes of magnitude 7.0 and above play a leading role in the number of deaths caused by earthquakes.(3)Secondary geological disasters mainly occur in the central and western regions.The Secondary geological disasters that caused deaths were mainly concentrated in the four provinces of Yunnan,Sichuan,Qinghai,and Gansu with complex terrain.There are many small earthquakes in Yunnan and Sichuan that were completely killed by Secondary Geological Disasters.On the basis of classifying the influencing factors of earthquake deaths and calculating the correlation between influencing factors and earthquake deaths,typical earthquake casualty assessment models were selected for comparative analysis according to the principle of different modelling parameters(influencing factors).The results show that:(1)When the magnitude of the earthquake is less than 5.5,the results of the different models are very close to the actual number of deaths and the models can be used for blind post-earthquake assessment.When the magnitude is between 5.5and 6.5,the assessment results of the models are in the same order of magnitude as the actual deaths.When the magnitude of the earthquake is greater than 6.5,the assessment results of the models differ more from the actual number of deaths and need to be corrected for the actual situation.(2)The current Earthquake Death Assessment Model has a large error between the assessment results and the actual number of deaths in areas with poor terrain conditions and low seismic performance of buildings or areas prone to secondary geological disasters.It needs to be combined with the geographical environment and socio-economics of the disaster area,Population spatial distribution and other data are comprehensively analyzed to support emergency decision-making.In order to further improve the practicability of Earthquake Death Assessment Model,comprehensively considering the evaluation characteristics of Earthquake Death Assessment Model and the lack of data on the area of the disaster area within a short period of time after the earthquake,an attempt was made to apply the Influence Field area calculated based on the Intensity Attenuation Formula to the earthquake casualty assessment.Trigger simulated earthquakes in the northwest,southwest,and east regions,use the Intensity Attenuation Formula to calculate area of Influence Field,and bringing it into the Li Wen Model to calculate the number of deaths.Discuss the value range of the correction parameters of influence field area by magnitude,and establish Earthquake Death Assessment Model of different magnitudes.In addition,based on the death information of secondary geological disasters,a linear relationship between the number of deaths caused by secondary geological disasters and the number of earthquake deaths was established,the evaluation results of the Earthquake Death Assessment Model were revised,and the earthquakes caused by secondary earthquake disasters were used for verification.