| Earthquake has the characteristics of frequent occurrence,strong burstiness,large intensity and shallow depth,which has caused heavy casualties and brought huge economic losses to our country.The seismic intensity is different from the magnitude.As an index to measure the degree of earthquake damage,it can reflect the damage caused by the earthquake to a certain extent,and explain the impact of the earthquake on different regions.By analyzing the seismic damage data of destructive earthquakes,the authors found that earthquake damage such as building damage,human casualties,and engineering structure damage was mainly concentrated in high seismic intensity region.At present,there are still some limitations in the study of rapid determination of high seismic intensity region,which mainly shows that the seismic intensity attenuation relation does not take into account the effect of the type of fault,and the aftershock information used in the dynamic correction stage is restricted by the time of acquisition.Therefore,after the earthquake,especially after the destructive earthquake,quickly and accurately determine the range of high seismic intensity region plays a crucial role in formulating emergency rescue plans and deploying rescue forces.This paper collected the data of M?5.6 destructive earthquake since 1966 and used ArcGIS to digitize the seismic intensity map.We give the magnitude,fault properties,topography,focal mechanism solution,intensity areas of ? and above it,data of long axis and short axis for each earthquake case.By analyzing historical earthquake cases,the intensity areas which magnitude range from 6.5 to 7.9,equal or above ? and magnitude 8 or exceed 8,equal or above ? will be regarded as high seismic intensity region.On the one hand,the relationship between the magnitude of different types of earthquakes and the area of high seismic intensity region is studied.For the strike-slip and dip-slip earthquakes,the fitting curves of the magnitude and the area of high seismic intensity region are given respectively.On the other hand,the author analyzed the distribution characteristics of high seismic intensity region in different types of earthquakes.The matching relations between different earthquakes magnitude and high seismic intensity region's long and short axes is given.A method for determining high seismic intensity region,which comprehensively considers fault properties,focal mechanism,topography is proposed.In this paper,the seismic damage data of destructive earthquakes and the fitting curves between the magnitude and the area of high seismic intensity region and the long or short axis are analyzed.The analysis results are drawn as follows.1)The strike-slip earthquakes in mainland China are more than the dip-slip earthquakes and the dip-slip earthquakes in the northwest of China are more than those in other regions.Most of the earthquakes occurring in the Sichuan-Yunnan region are strike-slip earthquakes.2)In the condition that the strike-slip earthquake has same magnitude,the area of the high seismic intensity region is relatively large in noth china,in northwest China is second and in Sichuan-Yunnan region is relatively small.3)Generally,the range of high seismic intensity region of dip-slip earthquake is larger than the strike-slip earthquake with the same magnitude.4)For strike-slip earthquakes,the distribution of high seismic intensity region is basically a symmetrical ellipse.Because the stress of strike slip fault is the shear force from both sides and two fault walls moves along strike of fault plane.5)For dip-slip earthquakes,the distribution of high seismic intensity region may be a symmetrical ellipse.The specific distribution is affected by the physical properties of both sides of the fault and the fault itself.6)For foiding earthquakes,the distribution characteristics of high seismic intensity region should be specifically analyzed based on the information of fault dislocation and fold uplift. |
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